Recent Advances in Battery Safety and Recycling. A Virtual Issue: Raphaële Clément, Kelsey Hatzell, and Yang-Kook Sun;  ACS Energy Lett. 2023, 8, 10, 4524–4527 (https://doi.org/10.1021/acsenergylett.3c01939)

Abstract

As the demand for storage batteries continues to increase, safety (including improved quality control and operational stability) and end-of-life management considerations are becoming increasingly important.1–7 Although aqueous batteries and all-solid-state batteries have emerged as intrinsically safe energy storage systems, the majority of today’s commercial devices still rely on flammable, nonaqueous (organic) electrolytes. The use of such organic electrolytes requires thermal management strategies that reduce pack-level energy density, motivating the design of novel, nonflammable electrolytes.8–14 Furthermore, a fundamental understanding of electrode working principles and degradation processes is key to improving the stability of electrode–electrolyte interfaces, especially when considering new cathode and anode chemistries.15–18 In addition to enhancing battery safety, developing effective recycling methods for spent battery materials is needed to ensure the sustainability and environmental-friendliness of electrochemical energy storage devices.19–23 This virtual issue presents a collection of papers published in ACS Energy Letters and offers a bird’s eye view on state-of-the-art developments in the area of battery safety and recycling.

Special Issue “GIS Applications in Green Development”: Yannis Maniatis; Appl. Sci. 2023, 13, 10856. https://doi.org/10.3390/app131910856

Abstract

In the context of climate change, the role of Geographic Information Systems (GIS) in green developments cannot be overstated. The application of smart GIS is the linchpin for decision makers tasked with designing and monitoring climate-conscious solutions at local, national, and international scales. With 75% of the Earth’s surface now impacted by human activities, it is imperative to expand the use of smart GIS to predict and mitigate the impact of these activities across forests, oceans, urban and rural areas, transportation networks, and production sites. This Special Issue of Applied Sciences, titled “GIS Applications in Green Development”, explores the pivotal role of GIS in advancing sustainability across diverse domains. The five papers presented in this Special Issue consider the potential intersection of GIS and green developments in urban planning, renewable energy integration, disaster management, and the energy sector. According to Ostapenko et al. [1], the potential to implement renewable energy sources in Ukraine is scrutinized using global and local Geographic Information Systems (GIS). The study highlights GIS’s prowess in identifying suitable territories for renewable energy development, assessing technical potential and facilitating the integration of renewable energy technologies in Ukraine’s energy sector. Zorzano-Alba et al. [2] addressed the sensitive issue of the visual impact associated with renewable energy infrastructure, introducing a novel methodology for identifying optimal locations for photovoltaic power plants, especially in areas of cultural or scenic significance. Maniatis et al. [3] focused on fire risk mapping in the context of climate change. The authors presented an innovative approach, incorporating recent land cover changes, to highlight regions with a high fire risk. Through the integration of a support vector machine (SVM) algorithm and the analytic hierarchy process (AHP) within a GIS framework, the authors created a robust fire risk estimation model. The model identifies high-risk areas in the Dadia-Lefkimi-Soufli National Forest Park, Greece, (although it can be adapted for other regions) reinforcing the vital role of GIS in disaster management. Pinna et al. [4] offer a comprehensive assessment of Sardinia’s rooftop photovoltaic potential using GIS data and an efficient shadow calculation algorithm. Their innovative approach provides a high-resolution, full census evaluation of the photovoltaic potential, which can be applied on a regional scale. By estimating not only the geographic but also the technical and economic potential, the paper exemplifies how GIS facilitate large-scale renewable energy planning. Yildiz [5] explores the wind energy potential of Balıkesir Province, Turkey, through GIS functions. The study employs wind speed data from meteorological stations and extrapolates it to create a wind speed map, enhancing this methodology by using an equation for turbine placement that is compliant with national regulations. This innovative approach enables the calculation of wind energy potential across the province, contributing to the knowledge regarding renewable energy assessments using GIS. The collection of papers in this Special Issue emphasizes that GIS are more than a technology; in fact, they are an indispensable tool in the quest for green developments and sustainable management. By providing insights, data-driven decision support, and innovative methodologies, GIS empower us to address the profound environmental challenges of our time.

Comprehensive Energy Analysis of Vehicle-to-Grid (V2G) Integration with the Power Grid: A Systemic Approach Incorporating Integrated Resource Planning Methodology:  Marcos Frederico Bortotti, Pascoal Rigolin, Miguel Edgar Morales Udaeta and José Aquiles Baesso Grimoni; Appl. Sci. 2023, 13, 11119. https://doi.org/10.3390/app132011119

Abstract

This work aims at a comprehensive assessment of the impact of vehicle-to-grid (V2G) technology on both demand and supply sides, considering integrated resource planning for sustainable energy. By using a computational tool and evaluating the complete potentials, we divide the analysis into four dimensions: environmental, social, technical, economic, and political. Each dimension is further subdivided, allowing for a detailed characterization of the impacts across these various aspects. Our approach employs a simple yet effective algebraic method using matrices to evaluate all the elements involved in the V2G system. This case study focuses on the environmental and technical–economic aspects of integrating V2G technology into a city with industrial parameters. Our findings reveal improvements and future challenges to all four dimensions, including direct and indirect reductions in CO2 emissions. However, the limited availability of specific data in the social and political scopes highlight the need for further research in these areas. This study lays the groundwork for future investigations to explore the social and political implications of V2G technology, offering significant potential for future studies.

A Qualitative Study on Artificial Intelligence and Its Impact on the Project Schedule, Cost and Risk Management Knowledge Areas as Presented in PMBOK®:  Thordur Vikingur Fridgeirsson, Helgi Thor Ingason, Haukur Ingi Jonasson and Helena Gunnarsdottir;  Appl. Sci. 2023, 13, 11081. https://doi.org/10.3390/app131911081

Abstract

The aim of this paper is to study the main areas in which artificial intelligence (AI) will impact the field of project management in relation to cost, risk and scheduling. The research model was based on a previous study of the ten project management knowledge areas presented in PMI’s PMBOK 6th edition, where project schedule, cost and risk management knowledge areas were identified as being the ones most likely to be affected by the development of AI. A group of graduates from a Master of Project Management program were assessed in an online questionnaire, reflecting the PMBOK’s elements of best practices and how AI will affect the project management profession in the future. Different elements of the three knowledge areas were considered to be affected more by AI than others. The schedule baseline is the element believed to be affected the most out of the project schedule management elements. For project cost management, the estimation of resource costs is believed to be affected the most. In the case of project risk management, the application of AI will have the strongest impact on the probability and impact formats.

The Microplastics Cycle: An In-Depth Look at a Complex Topic:  Kishore Kumar Gopalakrishnan, Rohith Sivakumar  and Donna Kashian; Appl. Sci. 2023, 13, 10999. https://doi.org/10.3390/app131910999

Abstract

Microplastics, or plastic particles smaller than 5 mm in size, have become ubiquitous in the environment, found in places ranging from remote deep ocean trenches to minute dust particulates. From the breakdown of larger plastic products and the release of synthetic clothing fibers, these particles enter the ecosystem and cycle through the various components including aquatic, terrestrial, and human systems. Due to their durability, capacity to adhere to other toxic compounds, and potential effects on humans and ecosystems, microplastics have recently risen to the forefront of environmental and health concerns. To address these critical issues, there has been a surge in research related to the microplastics cycle, examining where they originate, how and where they travel, and their environmental and human health impacts. Research on the microplastic cycle is often broken down into its various individual components such as sources, fate, and effect, and further scattered through the literature are focuses on specific environments such as land, oceans, and freshwater, as well as on human health. Here, we review the current state of the literature on the microplastic cycle across its various environmental reservoirs. In-depth examination of the microplastics cycle is necessary for understanding the scope of the problem and developing viable solutions or mitigation strategies, such as reducing plastic production and promoting recycling. Understanding the complex microplastics cycle is an urgent issue that necessitates multidisciplinary research and action.

Structural, Dielectric, and Mechanical Properties of High-Content Cubic Zirconia Ceramics Obtained via Solid-State Synthesis: Sholpan G. Giniyatova, Artem L. Kozlovskiy, Rafael  I. Shakirzyanov, Natalia O. Volodina, Dmitriy I. Shlimas and Daryn B. Borgekov; Appl. Sci. 2023, 13, 10989. https://doi.org/10.3390/app131910989

Abstract

In this work, the structural, electrical, and mechanical properties and phase composition of high-content cubic zirconium oxide ceramics stabilized with Ca were investigated. The novelty of this work lies in evaluating the potential use of porous ceramics obtained using calcium carbonate as a matrix for dispersed nuclear fuel. Experimental samples were prepared using solid-phase synthesis through sintering in air at 1500 ◦C. The X-ray diffraction method and Raman spectroscopy showed that the fraction of the cubic zirconium oxide ZrO2 -c phase gradually increased as the mass concentration changed from Cw = 0.00 to Cw = 0.15, and the CaZrO3 phase was present at concentrations of Cw = 0.20 and Cw = 0.25. When the phase composition was altered, significant changes occurred in the internal microstructure of the ceramics due to the processes of grain sintering and pore formation. Quantitative XRD analysis demonstrated the incorporation of Ca into the cubic structure of the ZrO2 -c polymorph. Dielectric spectroscopy at low frequencies revealed that the synthesized ceramics had a dielectric constant of 16.8–22 with a low dielectric loss of ~ 0.005. The microhardness value at a load of 200 kgf (HV0.2) of the obtained samples varied between 5 and 12 GPa and depended on the internal microstructure and phase composition. The obtained results clearly indicate that the mechanical and electrical properties and phase composition of synthesized ceramics make them suitable as a matrix for dispersed nuclear fuels.

Effect of Multiple Reverse Transformation Treatments on Grain Refinement and Mechanical Properties of Biomedical Co–Cr–Mo–N Alloys Fabricated by Electron Beam Melting:  Hao Wang, Toshimi Miyagi  and Akihiko Chiba; Materials 2023, 16, 6528. https://doi.org/10.3390/ma16196528

Abstract

We investigated the improvement of mechanical properties of biograde Co–28Cr–6Mo– 0.11N alloy prepared by electron beam melting through grain refinement via multiple reverse transformations. While the effects of single and double reverse transformation treatments on the microstructure have been investigated in previous studies, we investigated the effects of multiple reverse transformation heat treatments. The particle size was refined to 1/4, and the yield strength, tensile silence strength, and elongation were enhanced to 655 MPa, 1234 MPa, and 45%, respectively, satisfying ASTM F75 standards. Moreover, a mixed phase of ε and γ was observed to provide higher yield strength than a single γ structure. The dominant behavior in the γ → ε phase transformation at 1073 K was obvious. Grain growth was suppressed by the grain-boundary pinning effect of the Cr2N phase during reverse transformation to the γ phase. Because no fracture was caused by precipitates such as σ, η, and Cr2N phases, the influence of the precipitates on the tensile properties was small.

Effect of the Equal Channel Angular Pressing on the Microstructure and Phase Composition of a 7xxx Series Al-Zn-Mg-Zr Alloy:  Anwar Qasim Ahmed, Dániel Olasz, Elena V. Bobruk, Ruslan Z. Valiev and Nguyen Q. Chinh;  Materials 2023, 16, 6593. https://doi.org/10.3390/ma16196593

Abstract

A supersaturated Al-4.8%Zn-1.2%Mg-0.14%Zr (wt%) alloy was processed by the equalchannel angular pressing (ECAP) technique at room temperature in order to obtain an ultrafinegrained (UFG) microstructure having an average grain size of about 260 nm. The hardness and microstructural characteristics, such as the phase composition and precipitations of this UFG microstructure were studied using depth-sensing indentation (DSI), transmission electron microscopy (TEM), as well as non-isothermal scanning of differential scanning calorimetry (DSC), and compared to the properties of the un-deformed sample. Emphasis was placed on the effect of the UFG microstructure on the subsequent thermal processes in DSC measurements. It has been shown that the ECAP process resulted in not only an ultrafine-grained but also a strongly precipitated microstructure, leading to a hardness (2115 MPa) two and a half times higher than the initial hardness of the freshly quenched sample. Because of the significant changes in microstructure, ECAP has also a strong effect on the dissolution (endothermic) and precipitation (exothermic) processes during DSC measurements, where the dissolution and precipitation processes were quantitatively characterized by using experimentally determined specific enthalpies, ∆H and activation energies, Q.

Superconducting In Situ/Post In Situ MgB2 Joints:  Bartlomiej Andrzej Glowacki; Materials 2023, 16, 6588. https://doi.org/10.3390/ma16196588

Abstract

The superconducting joints of superconducting in situ MgB2 wires have been of great interest since the first MgB2 wires were manufactured. The necessity of joining fully reacted wires in applications such as NMR brings complexity to the methodology of connecting already reacted wires sintered under optimised conditions via a mixture of Mg + 2B and subsequential second heat treatment to establish fully superconducting MgB2 joints. Some of the data in the literature resolved such a procedure by applying high cold pressure and sintering at a low temperature. A topical review publication did not address in depth the question of whether cold sintering is a potential solution, suggesting that hot pressing is the way forward. In this paper, we discuss the potential joint interfacial requirements, suggesting a thermo-mechanical procedure to successfully form a superconductive connection of two in situ reacted wires in the presence of Mg + 2B flux. The critical current at 25 K of the researched junction achieved 50% Ic for an individual in situ wire.

Development of High-Performance Hot-Deformed Neodymium–Iron–Boron Magnets without Heavy Rare-Earth Elements:   Keiko Hioki; Materials 2023, 16, 6581. https://doi.org/10.3390/ma16196581

Abstract

Neodymium–iron–boron magnet is an essential material for the traction motors of green vehicles because it exhibits the highest maximum energy product, (BH)max, out of all permanentmagnet materials. However, heavy rare-earth elements such as dysprosium and terbium, which are scarce resources, are added to these magnets to improve their heat resistance. To address this resource problem, considerable efforts have been made to reduce the composition of heavy rare-earth elements in these magnets without causing a significant reduction in coercivity. Hot-deformed Nd-Fe-B magnets are a category of Nd-Fe-B magnets where precious materials such as heavy rare-earth elements can be eliminated or reduced to maintain high coercivity owing to their fine microstructure. Although they are not often used for the fabrication of high-performance magnets due to their complicated production process and the difficulty in controlling their fine microstructure, after the rare-earth crisis in 2020, these magnets have begun to attract attention as a material that could increase coercivity when controlling their microstructures. This paper provides an overview of hot-deformed magnets and the efforts made to improve their properties by controlling their microstructures.

Synthesis and Investigation of Properties of Beryllium Ceramics Modified with Titanium Dioxide Nanoparticles:  Alexandr Pavlov, Zhuldyz Sagdoldina, Almira Zhilkashinova, Nurtoleu Magazov, Zhangabay Turar and Sergey Gert;  Materials 2023, 16, 6507. https://doi.org/10.3390/ma16196507

Abstract

Samples of beryllium ceramics, with the addition of micro- and nanoparticles TiO2, have been obtained by the method of thermoplastic slip casting. The microstructure of batch ceramics, consisting of micropowders and ceramics with TiO2 nanoparticles sintered at an elevated temperature, has been investigated. It was found that the introduction of TiO2 nanoparticles leads to changes in the mechanisms of mass transfer and microstructure formation, and the mobility of TiO2 at interfacial grain boundaries increases, which leads to the formation of elements of a zonal shell structure. The reduction of intergranular boundaries leads to an increase in density, hardness, and mechanical strength of ceramics. The whole complex of properties of the synthesized material, with the addition of TiO2 nanoparticles in the amount of 1.0–1.5 wt.%, leads to an increase in the ability to absorb electromagnetic radiation in the frequency range of electric current 8.2–12.4 GHz. The analysis and updating of knowledge on synthesis, and the investigation of properties of beryllium ceramics modified by nanoparticles, seems to be significant. The obtained results can be used in the creation of absorbers of scattered microwave radiation based on (BeO + TiO2 ) ceramics.

Investigating the Effect of Heat Treatment on the Microstructure and Hardness of Aluminum-Lithium Alloys:  Lida Radan, Victor Songmene , Yasser Zedan and Fawzy H. Samuel;  Materials 2023, 16, 6502. https://doi.org/10.3390/ma16196502

Abstract

In this study, the effects of heat treatment on the microstructure and strength (microhardness) of an aluminum–lithium (Al-Li) base alloy containing copper (Cu) and scandium (Sc) were investigated, with a view to enhancing the alloy performance for aerospace applications. The heat treatment conditions were investigated to understand the precipitation behavior and the mechanisms involved in strengthening. Aging was carried out at temperatures of 130 ◦C and 150 ◦C for aging times of 1 h, 2.5 h, 5 h, 10 h, 15 h, 25 h, 35 h, and 45 h at each temperature for Al-Li alloy and at 160 ◦C, 180 ◦C, and 200 ◦C for aging times of 5 h, 10 h, 15 h, 20 h, 25 h, and 30 h at each temperature for Al-Li-Cu and Al-Li-Cu-Sc alloys. The investigation revealed that both solution heat treatment and artificial aging had a notable impact on strengthening the hardness of the alloy. This effect was attributed to the characteristics of the precipitates, including their type, size, number density, and distribution. The addition of copper (Cu) and scandium (Sc) was observed to have an impact on grain size refinement, while Cu addition specifically affected the precipitation behavior of the alloy. It led to remarkable changes in the number density, size, and distribution of T1 (Al2CuLi) and θ’ (Al2Cu) phases. As a result, the hardness of the alloy was significantly improved after the addition of Cu and Sc, in comparison with the base Al-Li alloy. The best heat treatment process was determined as: 580 ◦C/1 h solution treatment +150 ◦C/45 h artificial aging for Al-Li alloy and 505 ◦C/5 h solution treatment +180 ◦C/20 h artificial aging for Al-Li-Cu and Al-Li-Cu-Sc alloys.

Dissolution Behavior of Lime with Different Properties into Converter Slag:  Mengxu Zhang, Jianli Li, Cao Jia and Yue Yu; Materials 2023, 16, 6487. https://doi.org/10.3390/ma16196487

Abstract

China’s 2022 crude steel production soared to an impressive 1.018 billion tons, and steel slag constituted approximately 10% to 15% of this massive output. However, a notable hindrance to the comprehensive utilization of steel slag arises from the fact that it contains 10% to 20% of free calcium oxide (f-CaO), resulting in volume instability. To address this challenge, our study delved into the dynamic transformation of the interface between lime and slag, as well as the fluctuations in the dissolution rate of lime. An Electron Probe Micro Analyzer, equipped with an energy-dispersive spectrometer, was employed for the analysis. Our findings revealed that the configuration of the reaction interface between quicklime and slag underwent alterations throughout various phases of converter smelting. At a temperature of 1400 ◦C, several significant transformations occurred, including the formation of a CaO-FeO solid solution, (Ca, Mg, Fe) olivine, and low-melting point (Ca, Mg) silicate minerals. With the gradual reduction in FeO content, a robust and high-melting 2CaO·SiO2 layer emerged, generated through the interaction between CaO and (Ca, Mg, Fe) olivine. Furthermore, for lime with a particle size of 20 mm and a calcination rate of 0%, the thickest layer of 2CaO·SiO2 was observed after 120 s of dissolution in slag A2 at 1400 ◦C. Overall, the dissolution rates of lime with different particle sizes in slag A1 to A4 showed a gradual increase. On the other hand, the dissolution rates of lime with different calcination rates in slag A1 to A4 exhibited an initial increase, followed by a decrease, and then another increase. The formation of a high-melting point and continuous dense 2CaO·SiO2 layer during the dissolution process hindered the mass transfer between lime and slag.

Fe3O4 Magnetic Nanoparticles Obtained by the Novel Aerosol-Based Technique for Theranostic Applications:  Piotr Pawlik, Barbara Błasiak, Marcin Pruba, Arkadiusz Miaskowski, Oskar Moraczynski, Justyna Miszczyk, Boguslaw Tomanek  and Joanna Depciuch; Materials 2023, 16, 6483. https://doi.org/10.3390/ma16196483

Abstract

This work is aimed at presenting a novel aerosol-based technique for the synthesis of magnetite nanoparticles (Fe3O4 NPs) and to assess the potential medical application of their dispersions after being coated with TEA-oleate. Refinement of the processing conditions led to the formation of monodispersed NPs with average sizes of ∼5–6 nm and narrow size distribution (FWHM of ∼3 nm). The NPs were coated with Triethanolammonium oleate (TEA-oleate) to stabilize them in water dispersion. This allowed obtaining the dispersion, which does not sediment for months, although TEM and DLS studies have shown the formation of small agglomerates of NPs. The different behaviors of cancer and normal cell lines in contact with NPs indicated the diverse mechanisms of their interactions with Fe3O4 NPs. Furthermore, the studies allowed assessment of the prospective theranostic application of magnetite NPs obtained using the aerosol-based technique, particularly magnetic hyperthermia and magnetic resonance imaging (MRI).

Inventory of PCDD/Fs and Fly Ash Characteristics during the e-Waste and Municipal Solid Waste Co-Incineration Process: Xiaoqing Lin, Yuxuan Ying, Xiaoxiao Wang, Yunfeng Ma, Minjie Li, Qunxing Huang  and Xiaodong Li;  Energy Fuels 2023, 37, 10, 7302–7313 (https://doi.org/10.1021/acs.energyfuels.3c00835)

Abstract

In the face of a challenging situation for yearly e-waste (EW) increment and disposition, EW co-incineration (EWC) with municipal solid waste (MSW) is a promising solution whose emission characteristics remain unclear. This study is conducted in a 400 tons/day MSW incineration (MSWI) plant to characterize polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and fly ash (FA) properties. Analytical methods include high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) for PCDD/F determination, as well as X-ray diffraction (XRD), X-ray fluorescence (XRF), ion chromatography (IC), and leaching toxicity test for FA. The results indicate that toxic PCDD/F amounts are doubled by EWC in both primary exhaust gas (EG) and FA with international toxic equivalent quantity (I-TEQ) concentrations of 19.00 ± 6.32 ng I-TEQ/Nm3 and 1.33 ± 0.56 ng I-TEQ/g. After the clean-up of the air pollution control system (APCS), emitted PCDD/Fs in solid and gas phases, as well as major air pollutants (CO, NOx, SO2, HCl, and particulate matter), are permissive within the limit values of national standards GB 18485-2014 and GB 16889-2008. Distribution patterns for 136 PCDD/F isomers are analogous in both MSWI and EWC conditions. De novo synthesis is always the major formation route for both EWC and MSWI conditions, while dibenzodioxin/dibenzofuran (DD/DF) chlorination also contributes. The generation of 136 PCDD/Fs is enhanced by EWC, and the correlation coefficients of Cl and Cu in the fuel with the generation of 136 PCDD/F isomers are found to be R = 0.92 and 0.88, respectively. The main components in FA from MSWI and EWC differ less, both containing CaO, SiO2, and Al2O3. However, Cl and Cu contents, as well as leaching toxicity in FA are elevated by EW. Heavy metals, except for Cd, Ni, and Pb, meet the requirement of the standard.

Review of Phosphorus Chemistry in the Thermal Conversion of Biomass: Progress and Perspectives:  Emil O. Lidman Olsson, Peter Glarborg, Kim Dam-Johansen, and Hao Wu;  Energy Fuels 2023, 37, 10, 6907–6998 (https://doi.org/10.1021/acs.energyfuels.2c04048)

Abstract

Phosphorus is vital for all life, which means that phosphorus is present in all biomass to some extent. Some types of biomass, such as certain agricultural residues, animal biomass, and sewage sludge, contain high levels of phosphorus. In thermal conversion of biomass, high levels of phosphorus can cause various operational problems. Extensive work has been carried out to understand the phosphorus chemistry taking place at higher temperatures. However, until now, knowledge about transformation chemistry and fate of phosphorus during thermal conversion of biomass was not easily accessible in one place. In this work, the outcome of an extensive literature review has been summarized. First, an introduction to the role of phosphorus in biomass, and in what forms it may be present, is given. Different analytical techniques relevant for characterization of phosphorus in biomass, biomass char, and biomass ash are described. A classification of phosphorus-rich biomass is proposed, and the potential of different phosphorus-rich biomass types is presented. To provide a common basis for the field of high-temperature phosphorus chemistry, fundamental chemistry relevant for thermal conversion of biomass is first discussed. This includes the gas phase chemistry and reaction pathways of light phosphorus species, pyrolysis, and combustion of organophosphorus compounds, and solid, liquid, and gaseous interactions with other ash-forming elements. Thereafter, an in-depth review of phosphorus transformations in biomass, including decomposition of organic phosphorus, ash transformations in the condensed phase, release to the gas phase, and formation of particulate matter in the flue gas follows. Finally, the review covers research focusing on phosphorus in different application aspects, such as the use of phosphorus as an additive to mitigate operational problems related to slag and deposit formation, the behavior of phosphorus in fluidized bed technologies, corrosion, and the deactivation of SCR catalysts.

Hierarchical Graphitic Carbon Nitride–Zeolitic Imidazolate Framework-67 Nanostructures Adorned on Calcium Molybdate Nanospheres for High-Performance Supercapacitor Applications: Ramanadha Mangiri, Chaehyeon Lee, Kyeongmin Kim, Junbeum Lee, and Eunhyea Chung; Energy Fuels 2023, 37, 10, 7479–7489 (https://doi.org/10.1021/acs.energyfuels.3c00417)

Abstract

Complex composite nanomaterials have recently received attention because of their enhanced electrochemical performance compared to single-structured materials. In this study, we synthesized calcium molybdate (CaMoO4) particles with a spherical shape and conducted surface modification to fabricate composite heterostructures on the CaMoO4 backbone using a simple two-step hydrothermal technique. To test their electrochemical characteristics, the produced hierarchical heterostructures were used as an electrode material for supercapacitors, exhibiting a cycling efficiency of 94% after 5000 cycles, a specific capacitance of 586 C g–1 at a current density of 1 A g–1, and good reversibility. These results demonstrate that the development of hierarchical heterostructures can significantly improve the electrochemical properties of materials by creating well-defined interfaces, increasing the surface area, and promoting efficient charge transfer, making them highly attractive for various applications in the field of energy storage and conversion.

Synergistic Chemical Looping Process Coupling Natural Gas Conversion and NOx Purification: Sonu Kumar, Pinak Mohapatra, Rushikesh K. Joshi, Matthew Warburton, and Liang-Shih Fan;  Energy Fuels 2023, 37, 10, 7268–7279 (https://doi.org/10.1021/acs.energyfuels.3c00254)

Abstract

We present a novel low-temperature chemical looping combustion scheme for simultaneous natural gas conversion into a sequestration-ready CO2 stream and NOx purification. The scheme employs nickel oxide (NiO) supported on ZrO2 as the oxygen carrier. In the process, CH4 reduces the oxidized carrier to Ni/ZrO2 in a co-current moving bed reactor, which is then oxidized back to NiO/ZrO2 by the NOx-laden flue gas in a fluidized bed reactor, completing the oxygen carrier loop. Thermodynamic studies demonstrate that the presence of CO2 does not significantly affect NOx purification performance at different flue gas flow rates. The operating temperatures of the reactors are selected based on NOx-temperature programmed oxidation (TPO) and CH4-temperature programmed reduction (TPR) experiments. Results show that the process can optimally operate at temperatures close to the combustion plants’ flue gas temperature of 400–500 °C, reducing the need for hot utilities. The study conducts comprehensive isothermal and autothermal analyses of the process to evaluate the effects of temperature and carrier flow rate on CH4 conversion, CO2 selectivity, carbon deposition, and NOx conversion. For the autothermal analysis, the CH4 reactor operates adiabatically, while the NOx reactor operates isothermally. Comparative studies with the conventional NOx selective catalytic reduction (SCR) process indicate an exergy efficiency and effective thermal efficiency (ETE) improvement of 9 and 18 percentage points, respectively. The findings suggest that this low-temperature chemical looping process is a promising solution for flue gas NOx treatment, utilizing cheaper natural gas as the reductant and eliminating environmental concerns, such as ammonia or urea slippage. Overall, this study contributes to the development of more efficient and sustainable methods for reducing NOx emissions.

Structural Transformation of Hydrated WO3 into SnWO4 via Sn Incorporation Enables a Superior Pseudocapacitor and Aqueous Zinc-Ion Battery: Harishchandra S. Nishad, Shobhnath P. Gupta, Nishat S. Khan, Ankush V. Biradar, Jaewoong Lee, Sagar M. Mane, and Pravin S. Walke; Energy Fuels 2023, 37, 10, 7501–7510 (https://doi.org/10.1021/acs.energyfuels.3c00556)

Abstract

The strategy of crystal structure transformation tunes the electrochemical properties favoring the energy storage performance of the electrode material. Herein, we prepared SnWO4 nanoflakes through Sn incorporation into the tungsten oxide matrix by a single-step wet chemical method. The crystal structure tuning occurs from the orthorhombic structure of hydrated tungsten oxide (WO3·H2O, i.e., HWO) to the hexagonal (SnWO4, i.e., SWO) structure. Simultaneously, the morphology tailoring from nanodisks of HWO to nanoflakes of SWO is realized as a result of the Sn ion exchange mechanism. Further, the electrochemical supercapacitor of SWO nanoflakes demonstrates almost 2-fold enhancement in the specific capacitance of 622 F g–1 at 0.5 A g–1 over HWO nanodisks (255 F g–1). Moreover, the asymmetric supercapacitor (ASC) of SWO//activated carbon (AC) exhibits the specific capacitance of 50 F g–1 at 1 A g–1, with the maximum energy density and power density of 18 Wh kg–1 and 7000 W kg–1, respectively. Furthermore, superior performance of the aqueous zinc-ion battery (AZIB) demonstrates the specific capacity of 75 mA h g–1 at 0.3 A g–1 along with 106% stability and 101% coulombic efficiency after 70 cycles. The improved performance of SWO nanoflakes in the pseudocapacitor and AZIB is attributed to crystal structure tuning, increasing conductivity, enhanced surface area, and Sn redox sites. Therefore, the SWO nanoflakes are favorable cathode materials for commercial energy storage devices.

Low-Temperature Selective Catalytic Reduction of NO with NH3 over a Biochar-Supported Perovskite Oxide Catalyst:  Xiaoxiong Fan, Lifang Hao, Xiangyu Gu, and Songgeng Li;  Energy Fuels 2023, 37, 10, 7339–7352 (https://doi.org/10.1021/acs.energyfuels.2c04291)

Abstract

Maintaining high denitration efficiency for the selective catalytic reduction with ammonia (NH3-SCR) at low temperatures is challenging. In this work, a modified biochar-supported perovskite oxide catalyst was synthesized and implemented to NO conversion in the low-temperature range of 100–250 °C. Different modification methods were compared, where the combination of nitric acid and air oxidation treatment endowed biochar with abundant acidic surface oxygen-containing groups and a higher specific surface area as a support. The perovskite oxide (LaMnO3) and the LaMnO3/biochar catalysts were prepared to investigate the interactions between the catalyst and the support. The LaMnO3/biochar catalyst exhibited excellent denitration efficiency and good N2 selectivity, achieving over 80% NO conversion within the entire temperature range of 100–250 °C (SN2 > 90%), and the highest NO conversion reached 95.8% at 225 °C (SN2 = 95.4%). This catalyst provided synergistic adsorption capacity for NH3 as a result of the acidic function of perovskite oxide and acidic oxygen-containing functional groups of the modified biochar support. Additionally, LaMnO3 showed an eminent redox capability for NO conversion due to the high content of Mn4+ and chemically adsorbed oxygen species. Finally, NH3-SCR reaction mechanisms were proposed on the basis of transient response experiments and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) characterization.

Li–B–Cu Anodes with a Stable Three-Dimensional Composite Skeleton for Lithium Metal Batteries: Pan He, Shaozhen Huang, Piao Qing, Dongping Chen, Kecheng Long, Haifeng Huang, Yuejiao Chen, Lin Mei, and Libao Chen; Energy Fuels 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acs.energyfuels.3c00884)

Abstract

Lithium metal is considered one of the most ideal anode materials as a result of its extremely high theoretical capacity and energy density. However, the problems of dendrite growth and volume change of lithium metal anodes are prone to cause safety hazards, which seriously restrict the development of their commercial applications. In this paper, Li–B–Cu composite anodes with a three-dimensional skeleton structure were prepared in situ via the vacuum melting method. The lithiophilic LiB fibers can effectively reduce the local current density based on which the addition of Cu further strengthens the structural stability of the electrode material and optimized interfacial electric field distribution, inhibiting the growth of lithium dendrites and the volume change of the anode. The electrode material achieves a long cycle (1700 h and 1 mAh cm–2) in symmetric cells and shows ultrastable performance in high-capacity cycling tests. Moreover, the Li–B–Cu composite anode exhibits better electrochemical performance when assembling full cells with S and highly loaded LiFePO4 as the cathode. This work verifies that alloying can achieve stable and reliable lithium metal anodes and provides ideas for the practical application of lithium metal batteries.

Optimized Synthesis of Nanostructured Trimetallic Mn–V–Fe Selenides with Battery-Type Behavior for High-Performance Hybrid Supercapacitors: Sara A. Teama, Heba M. El Sharkawy, and Nageh K. Allam;  Energy Fuels 2023, 37, 10, 7468–7478 (https://doi.org/10.1021/acs.energyfuels.3c00377)

Abstract

The design and synthesis of innovative materials with a specific architecture are necessary to advance the supercapacitor industry. Recently, transition metal selenides have been identified as an auspicious type of material for energy storage devices due to their enormous electronic conductivity and high theoretical capacitance. Consequently, mono- and diselenides have been extensively investigated. Trimetallic selenides, however, are infrequently reported, and their charge storage mechanism is still not fully understood. Herein, earth-abundant trimetallic Mn–V–Fe selenide (MVF-Se) is successfully fabricated via a two-step hydrothermal approach. The chemical composition, structure, and morphology of the as-synthesized material have been thoroughly characterized. The electrochemical tests revealed that the MVF-Se electrode possesses a high areal capacitance of 16,212.88 mF cm–2 at 1 mA cm–2 in the three-electrode configuration. In addition, the assembled asymmetric supercapacitor device by coupling MVF-Se and activated carbon as the positive and negative electrodes, respectively, demonstrates a desirable 0.56 mWh cm–2 energy density at a 1.0 mW cm–2 power density. After 17,000 charge/discharge cycles, the device exhibits robust cyclic stability with a 95% capacitance retention.

Hierarchical Composite from Carbon Nanofibers Wrapped SnS Core–Shell Nanoparticles as an Anode for Lithium-Ion Batteries: Chenxi Yue, Dan He, Long Qing, Yi Tang, Xianguang Zeng, Wei Jiao, Naiqiang Liu, Yu He, Wei Zhao, and Jian Chen;  Energy Fuels 2023, 37, 9, 6791–6799 (https://doi.org/10.1021/acs.energyfuels.3c00056)

Abstract

The significant capacity loss and pulverization caused by the dramatic increase in volume of Sn-based anodes during redox reactions severely limit their practical application in lithium-ion batteries. Herein, with the ultralong cycle life and high capacity Sn-based compounds (SnS-C/NS@CNFs), a self-supporting anode was prepared by electrospinning followed by the calcination scheme, which is a superb material for lithium storage since the buffer matrix reduces the volume expansion of Sn. In this strategy, SnS nanoparticles are scattered into a porous carbon framework using Sn-MOFs as a pore-forming template, which allows for easier extraction–insertion of Li-ions due to their inherent layered structure. Moreover, the nitrogen and S-doped carbon nanofibers not only serve as a barrier to impede the aggregation and volume expansion of SnS during cycling but also act as electrical pathways to enhance the conductivity of the electrodes. Having profited from the desirable nanostructures, the flexible three-dimensional cross-linked nanofibers were straightly used as a self-supporting anode for LIBs, displaying ultralong cycle life (455.8 mAh/g after 1000 cycles at 1 A/g) and exceptional rate performance (481 mAh/g at 2 A/g). This work offers a reliable and efficient method for fabricating flexible self-standing and durable electrodes.

Infrared and Raman Spectroscopy of Mullite Ceramics Synthesized from Fly Ash and Kaolin: Michal Ritz; Minerals 2023, 13(7), 864; (https://doi.org/10.3390/min13070864)

Abstract

Infrared spectroscopy and Raman spectroscopy were used to characterize mullite ceramics prepared from fly ash and kaolin by annealing at 1000 ◦C, 1100 ◦C, 1200 ◦C, and 1300 ◦C. IR spectroscopy confirmed the presence of SiO4 tetrahedra and AlO6 octahedra in samples. The presence of mullite has been confirmed at all temperatures. The presence of quartz has been confirmed up to a temperature of 1100 ◦C, and the presence of an amorphous form of SiO2 has been confirmed at temperatures of 1200 ◦C and 1300 ◦C. The transformation of quartz into the amorphous form of SiO2 at temperatures above 1100 ◦C is assumed. Transformation was performed on the percentage intensity decrease of the bending vibration of Si-O-Si (at about 450 cm−1 ) and Al-O-Si (at about 550 cm−1 ). Raman spectroscopy confirmed the presence of mullite at different stages of structural ordering (a well-ordered structure at a temperature of 1100 ◦C and a disordered structure at a temperature of 1300 ◦C).

Study of Dendromass Ashes Fusibility with the Addition of Magnesite, Limestone and Alumina:  Pavol Vadász, Beatrice Plešingerová, Dávid Medved’, Gabriel Sučik, Radka Bakajsová and Vladimír Petrov;  Minerals 2023, 13, 631  (https://doi.org/10.3390/min13050631)

Abstract

The fusibility of ash from woodchip combustion is characterised in the present work. The impact of the increase in MgO, CaO, and Al2O3 content in the bio-ash on the classification of ash into categories according to slagging and fouling indices was evaluated. The ash was characterized based on the chemical composition using slagging and fouling indices. However, these ash composition changes did not assign the ash into categories of the indices FU, SR, RS, and B/A (fouling, slagging, slag viscosity, basicity), with less ash inclination to slagging and fouling. The indices were primarily derived for ashes from coal combustion. The indices values characterizing the ash were compared with measured results of ash melting according to STN ISO 540. The measured ash fusibility values showed that the addition of magnesite, limestone, and alumina to dendro-ashes increases the DT (temperature of deformation), HT (temperature of hemisphere), and the AFI (ash fusibility index). There is no conformity between the values of the indices and the measurement of ash fusibility temperatures. In terms of temperatures in the combustion chamber, the measured sintering (Tsin) and DT are suitable for evaluating the tendency of ash to slagging and fouling as well as an accretion of ash particles sticking to the lining.

The Corrosion Effect of Fly Ash from Biomass Combustion on Andalusite Refractory Materials:  Jozef Vlček, Hana Ovčačíková, Marek Velička, Michaela Topinková, Jiří Burda and Petra Matejková; Minerals 2023, 13, 357 (https://doi.org/10.3390/min13030357)

Abstract

The main problem affecting the life of refractory linings in furnaces is alkaline corrosion formed during biomass combustion, especially in systems with SiO2–Al2O3 . This corrosion effect is very intensive compared to using conventional technologies designed for burning traditional fuels. This study focuses on the development of a new type of andalusite refractory material with a higher corrosion resistance to K2CO3 and fly ash after biomass combustion. The original andalusite refractory material is labeled A60PT0, with an oxide content of 60 wt.% Al2O3 and 37 wt.% SiO2 , a compressive strength parameter of 64 MPa, and an apparent porosity of 15%. In the experiment, four mixtures (labeled A60PT1–A60PT4) were modified primarily using the raw materials and granulometry. The fly ash was characterized by an X-ray diffraction analysis with the following phases: quartz, calcite, microcline, leucite, portlandite, and hematite. According to the X-ray fluorescence analysis, the samples contained the following oxides: 47 wt.% CaO, 12 wt.% K2O, 4.6 wt.% SiO2 , 3.5 wt.% MgO, and some minority oxides such as P2O5 , MgO, MnO, and Fe2O3 between 2 and 5 %. The tendency for slagging/fouling of the ash was determined with the help of the indexes B/A, TA, Kt , and Fu. The final material was a shaped andalusite refractory material labeled A60PT4 with a content of 65 wt.% Al2O3 and 36 wt.% SiO2. The properties of the andalusite material were a compressive strength of 106.9 MPa, an apparent porosity of 13%, and the recommended temperature of use up to 1300 ◦C. For corrosion testing, a static crucible test was performed according to the norm CSN CEN/TS 15418 and ˇ the company’s internal regulation. The exposure time of the samples was 2 h and 5 h at temperatures of 1100 ◦C and 1400 ◦C for K2CO3 and ash, respectively. For the evaluation of tested samples, an X-ray powder differential analysis, an X-ray fluorescence analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used.

Evaluation of As-Received Green Liquor Dregs and Biomass Ash Residues from a Pulp and Paper Industry as Raw Materials for Geopolymers Rafael Vidal Eleutério, Lisandro Simão, Priscila Lemes and Dachamir Hotza; Minerals 2023, 13, 1158 (https://doi.org/10.3390/min13091158)

Abstract

This study aimed to investigate the impact of as-received biomass fly ashes (BFA) and green liquor dregs obtained from a pulp and paper plant in Brazil as substitutes for metakaolin in geopolymeric formulations. The properties of this type of waste material vary widely between different industrial plants. This study refrains from subjecting the waste materials to any form of pretreatment, taking into account their organic matter and particle size heterogeneity, requiring extensive characterization to evaluate their influence on the compressive strength, apparent open porosity, and water absorption of the geopolymeric samples. The objective was to assess their potential for upcycling purposes as an alternative to energy-intensive materials, such as ordinary Portland cement (OPC) and advanced ceramics. This potential arises from the ability of alkaliactivated materials (AAM) to undergo curing at ambient temperatures, coupled with the possibility of compositions primarily derived from waste materials. To improve the sustainability of the products, the amorphous content of the raw material, which is more reactive than crystalline phases, was quantified and used as the base for mixture ratios. This approach aimed to reduce the requirement for alkaline activators, which have significant environmental impacts, while also increasing the waste content in the formulation. The incorporation of waste materials into the geopolymer matrix generally led to a reduction in the compressive strength compared to the benchmark metakaolin sample (19.4 MPa) but did not present a trend. The dregs led to values of 4.1 MPa at 25 wt% and 7.1 MPa at 50 wt%, a behavior that is somewhat counterintuitive, and BFA at 10 wt% presented 5.7 MPa. Nevertheless, the apparent open porosity remained at high levels for all the samples, close to 50%, and the compressive strength of most of them was over the values obtained for the metakaolinonly samples with mixture ratios calculated from the total composition instead of the amorphous composition. The decrease in strength and the increase in porosity were attributed to the specific characteristics of the waste materials, such as their high crystallinity, presence of organic matter, heterogeneous particle composition, and size. Overall, this study provides insight into the variations in geopolymerization based on the bulk and amorphous content of the aluminosilicate sources and how the characteristics of the waste materials influence the geopolymer matrix. It also highlights how calculating mixture ratios based on the amorphous composition improves the possibility of waste valorization through alkali activation. Additionally, it suggests that BFA and dregs might be effectively utilized in applications other than OPC substitution, such as adsorption, filtration, and catalysis.

Study on the Leaching Kinetics of Weathered Crust Elution-Deposited Rare Earth Ores by Hydroxypropyl Methyl Cellulose: Huifang Yang, Aoyang Sha, Zhengyan He, Chenjie Wu, Yuanlai Xu , Jingjing Hu, Zhigao Xu and Ruan Chi; Minerals 2023, 13, 1156 (https://doi.org/10.3390/min13091156)

Abstract

In the process of the in situ leaching of weathered crust elution-deposited rare earth ores (WCE-DREOs), there are many problems in the conventional leaching agent, such as a slow leaching rate, low leaching yield and long leaching period. In order to solve the above problems, 2.0 wt% ammonium sulfate was mixed with hydroxypropyl methyl cellulose (HPMC). The effects of the HPMC concentration, temperature, pH and flow rate on the leaching kinetics of rare earth (RE) and aluminum (Al) were investigated. The results showed that when the concentration of HPMC was 0.05 wt%, the leaching equilibrium time of RE and Al was about 60% shorter than that of single ammonium sulfate. With an increase in the leaching temperature, the leaching equilibrium time of RE and Al decreased, and the apparent activation energy of RE and Al was 23.13 kJ/mol and 17.31 kJ/mol, respectively. The leaching process was in line with the internal diffusion kinetic control model. When the pH of the leaching agent was 4.02~8.01, the leaching yield of RE and Al was basically the same, but the leaching yield of Al was greatly increased at pH 2.0 due to a large amount of adsorbed hydroxy-Al in the RE ore eluded. The leaching yield reached the maximum when the flow rate was 0.7 mL/min. The leaching time and the leaching cost of RE can be saved by the composite leaching agent. The results provide theoretical guidance for the development and industrial application of the new composite leaching agent.

The Role of Te, As, Bi, and Sb in the Noble Metals (Pt, Pd, Au, Ag) and Microphases during Crystallization of a Cu-Fe-S Melt:  Elena Fedorovna Sinyakova, Nikolay Anatolievich Goryachev, Konstantin Aleksandrovich Kokh, Nikolay Semenovich Karmanov  and Viktor Aleksandrovich Gusev; Minerals 2023, 13, 1150 (https://doi.org/10.3390/min13091150)

Abstract

Quasi-equilibrium directional crystallization was performed on a melt composition (at. %): 18.50 Cu, 32.50 Fe, 48.73 S, 0.03 Pt, Pd, Ag, Au, Te, As, Bi, Sb, and Sn, which closely resembles the Cu-rich massive ores found in the platinum-copper-nickel deposits of Norilsk. Base metal sulfides (BMS) such as pyrrhotite solid solution (Fe,Cu)S1±δ (Poss), non-stoichiometric cubanite Cu1.1Fe1.9S3 (Cbn*), and intermediate solid solution Cu1.0Fe1.2S2.0 (Iss) are progressively precipitated from the melt during the crystallization process. The content of noble metals and semimetals in the structure of BMS is below the detection limit of SEM-EDS analysis. Only tin exhibits significant solubility in Cbn* and Iss, meanwhile Pt, Pd, Au, Ag, As, Bi, Sb, and Te are present as discrete composite inclusions, comprising up to 11 individual phases, within their matrices. These microphases correspond to native Au, native Bi, hessite Ag2Te, sperrylite Pt(As,S)2 , hedleyite Bi2Te, michenerite PdTeBi, froodite PdBi2 , a solid solution of sudburite-sobolevskite-kotulskite Pd(Sb, Bi)xTe1−x, geversite PtSb2 , and a multicomponent solid solution based on geversite Me(TABS)2 , where Me = Σ(Pt, Pd, Fe, Cu) and TABS = Σ(Te, As, Bi, Sb, Sn). Most of the inclusions occur as thin layers between BMS grain boundaries or appear drop-shaped and subhedral to isometric grains within the sulfide matrix. Only a small fraction of the trace elements form mineral inclusions of sizes ≤ 0.5 µm in Poss, most likely including PtAs2 and (Pt,Pd)S. It is likely that the simultaneous presence of noble metals (Pt, Pd, Au, Ag) and semimetals (As, Te, Bi, Sb) in the sulfide melt leads to the appearance of liquid droplets in the parent sulfide melt after pyrrhotite crystallization. The solidification of droplets during the early stages of Cbn* crystallization may occur simultaneously with the cooling of later fractions of the sulfide melt, resulting in the formation of Iss. In addition, abundant gas voids containing micro-inclusions were observed in Cbn* and Iss. These inclusions showed similar chemical and mineral compositions to those in BMS matrices, i.e., the presence of gas bubbles did not affect the main features of noble metal fractionation and evolution. Therefore, it is reasonable to assume that ore particles suspended in the melt are either trapped by defects at the crystallization front or transported towards gas bubbles via the Marangoni effect.

Carbon Layer and CoO Nanosheet Dual-Encapsulated SiOx Particles for Ultra-High Specific Capacity Lithium-Ion Batteries:  Ying Huang, Xianping Du, Shuai Yuan, Zhenhe Feng, and Junhui Zou; Energy Fuels 2023, 37, 12, 8650–8658 (https://doi.org/10.1021/acs.energyfuels.3c00950)

Abstract

Silicon-based (Si-based) materials have attracted considerable attention due to their extremely high specific capacity, while the huge volume change up to 400% during cycling severely limits their widespread use. Silicon-oxygen (SiOx) anode materials, belonging to silicon-based materials, are considered to be more promising anode materials for practical applications due to their lower volume expansion without losing the high capacity. However, the existence of the volume expansion and the poor electrical conductivity of SiOx anode materials cannot be ignored. The encapsulation of SiOx particles by introducing a conductive carbon layer can greatly alleviate the volume expansion issue and improve the conductivity of the composites. In addition, to further boost the lithium storage capacity of the composites, the SiOx@C@CoO composites were obtained by an electrostatic self-assembly of CoO nanosheets onto the surface of SiOx@C materials. The introduction of CoO nanosheets increased the specific surface area of the composites, thereby enlarging the contact area with active Li and reducing the ion/electron transport radius, which in turn improved the lithium storage capacity of the composites. The final SiO+x@C@CoO composite has an excellent electrochemical performance, with a reversible capacity of 1120 mAh g–1 after 100 cycles at 0.2 A g–1.

Study on the Influence of Pre-Oxidation Treatment on Surface Wettability and Supercapacitive Performance of Coal-Based Activated Carbon: Shanxin Xiong, Xueni Zhao, Fengyan Lv, Wei Zhang, Nana Yang, Yukun Zhang, Xiaoqin Wang, Ming Gong, Chenxu Wang, and Zhen Li; Energy Fuels 2023, 37, 12, 8672–8680 (https://doi.org/10.1021/acs.energyfuels.3c01139)

Abstract

Coal possessing high fixed carbon content can be used for the preparation of activated carbon materials, including supercapacitance electrode carbon. Taixi anthracite has less ash content and high graphitization degree, which is a good candidate as a carbon source, while its low chemical activity affects the pore growth during the activated process. In this paper, using Taixi anthracite as the raw material, the effects of H2O2 pre-oxidation on the pore structure, surface chemical structure, and electrochemical properties of prepared activated carbon were studied. The results show that H2O2 successfully reduces the hydrophobic characteristics of the coal surface, which provides the possibility for the accessibility of the activator and the electrolyte. The activated carbon with H2O2 treatment at 15% concentration (AC-15%) shows high specific surface area (2016.50 m2/g), high specific capacitance (262 F/g), and high rate performance (63%), which is much higher than AC-0% without the pre-oxidation treatment. It is due to that the stable oxygen-containing functional groups (aldehyde and anthraquinone) on coal can improve the activity of activation carbon material and increase the wettability without affecting the electrical conductivity. In addition, the material shows high energy density and cyclic stability. This study provides an effective surface treatment approach for the preparation of a high-performance coal-based supercapacitance electrode material.

Recent Advances and Perspectives in Ru Hybrid Electrocatalysts for the Hydrogen Evolution Reaction: Yiwen Li and Ligang Feng; Energy Fuels 2023, 37, 12, 8079–8098 (https://doi.org/10.1021/acs.energyfuels.3c00749)

Abstract

The water-splitting reaction for green hydrogen generation requires highly efficient catalysts on the side for the hydrogen evolution reaction (HER), and metal ruthenium (Ru) is considered a promising catalyst as a result of its similar property in hydrogen-bonding ability but low cost compared to Pt-based materials. The performance is further boosted by the recently developed hybrid Ru-based electrocatalysts. To reveal the relationship between the hybrid catalyst systems and activity for Ru-based catalysts, the research progress of heterostructured Ru hybrid catalysts in the HER is reviewed in this effort. The enhancement of HER activity of Ru hybrid catalysts is first described on the basis of the synergistic effect, strain effect, and electronic effect, and then, the latest progress is discussed in three categories of single ruthenium catalysts, ruthenium-related compounds, and ruthenium alloy catalysts. It is concluded that the heterostructured interface engineering strategy plays an important role in enhancing the activity of Ru-based catalysts in the HER. In the end, the actual problems and challenges are discussed, e.g., the intrinsic activity and stability, application in the real device, etc. It is recommended to pay attention to the long-term stability, performance, and structural evolution as well as the application of the catalysts in the devices. It is hoped that this effort will help with understanding the progress of Ru-based hybrid catalysts in the field of HER catalysis.

Review on Ru-Based and Ni-Based Catalysts for Ammonia Decomposition: Research Status, Reaction Mechanism, and Perspectives: Tianxu Su, Bin Guan, Jiefei Zhou, Chunzheng Zheng, Jiangfeng Guo, Junyan Chen, Yaoyao Zhang, Yuheng Yuan, Wenkai Xie, Nanxin Zhou, Hongtao Dang, Bingyu Xu, and Zhen Huang;  Energy Fuels 2023, 37, 12, 8099–8127 (https://doi.org/10.1021/acs.energyfuels.3c00804)

Abstract

Hydrogen (H2) is a zero-carbon and high-energy-density fuel promising to replace fossil fuels for power generation and clean energy. However, hydrogen still faces enormous challenges in terms of production, transportation, and storage. Ammonia (NH3) is a promising H2 (17.7 wt %) carrier that easily overcomes the difficulties associated with H2 storage and transport. However, for the NH3 decomposition hydrogen production reaction, the biggest challenge at present is to achieve complete conversion of ammonia under a relatively high space velocity (about 30,000 mL·gcat–1·h–1) at low-temperature conditions (about 350 °C) with reasonable price catalysts. At present, the most efficient ammonia decomposition catalyst is a Ru-based catalyst doped with K, Ba, and Cs and supported on various carbon supports and metal oxides. Otherwise, the catalysts that exhibited the most outstanding activity among non-noble metal catalysts are nickel-based, and because of their low cost, nickel is regarded as a reasonable alternative candidate material for NH3 decomposition. Advances in the study of reaction kinetics of ammonia decomposition reactions and whether the rate-determining step of the ammonia decomposition reaction is the cleavage of the first N–H bond or the desorption of nitrogen gas are also discussed. This review provides a comprehensive consideration of the recent development of Ru-based and Ni-based catalysts and proposed mechanisms of ammonia decomposition on them are examined. The effects of preparation methods, support, and promoters on catalyst activity were studied and theoretical bases for the design of future catalysts are presented. At last, a brief introduction to catalytic membrane reactor technology in recent years is given. This review can serve as a comprehensive work for designing novel catalysts.

Desulfurization Characteristics of Carbide Slag during Circulating Fluidized Bed Coal Combustion: Liyao Li, Leming Cheng, Bo Wang, Zhangke Ma, and Weiguo Zhang; Energy Fuels 2023, 37, 12, 8364–8373 (https://doi.org/10.1021/acs.energyfuels.3c00863)

Abstract

At low loads, the desulfurization efficiency of circulating fluidized bed (CFB) boilers tends to decrease due to the deviation of low bed temperature from the optimal temperature required for limestone desulfurization. However, carbide slag, a waste product rich in Ca(OH)2 and possessing a low decomposition temperature, can be an economically viable alternative to limestone. In this study, the desulfurization characteristics during coal combustion with carbide slag addition were studied both in a fixed-bed reactor and a 30 kW CFB reactor. The effect of different reaction conditions on the desulfurization performance was evaluated. Results showed that the addition of carbide slag decreased SO2 emission effectively. A higher oxygen content prompted the improvement of the desulfurization efficiency. The carbide slag showed the highest desulfurization efficiency at about 800 °C. The desulfurization performance deteriorated when the temperature was beyond 800 °C. To explain this phenomenon, the micromorphology of carbide slag raw particle, calcined particle, and sulfated particle was observed by scanning electron microscopy. More holes formed on the surface of the particles after calcination. Besides, the outer surface of the holes formed more crystal grains with the increasing temperature. CaSO4 products covered the outer surface of the crystal grains after desulfurization. The crystal grain gaps on the surface of carbide slag were easily blocked at high temperatures, which resulted in the low desulfurization efficiency.

Mechanism of CO2 and H2O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation: Yukai Li, Dongdong Feng, Shaozeng Sun, Yijun Zhao, Wenda Zhang, and Chenxi Bai;  Energy Fuels 2023, 37, 14, 10721–10725 (https://doi.org/10.1021/acs.energyfuels.3c01080)

Abstract

The mechanism of the combined action of the C–CO2 and C–H2O reactions has yet to be clarified in the study of oxy-fuel combustion with wet flue gas recirculation (WFGR). The ultrahigh temperature (1573 K) and atmosphere of an industrial boiler are simulated in the flat flame burner reaction system (FFB-RS). The measurement of surface reactive groups and combustion reactivity of char uses Fourier transform infrared spectroscopy (FTIR) and a microfluidized bed reaction analyzer (MFBRA). The results show that char combustion reactivity has an excellent positive correlation with an O-containing reactive group. Above a 35% H2O concentration, its physical properties dominate, while below 35%, its chemical properties play a significant role. When the ratio of H2O/CO2 is close to 1, there is a synergistic relationship between the C–CO2 and C–H2O reactions, which did not occupy the same active sites, promoting the formation of O-containing reactive groups (33.83%) and alkyl complexes (19.6%) with a combustion reaction rate of 0.225%/s.

Effect of Residual Chloride in FAPbI3 Film on Photovoltaic Performance and Stability of Perovskite Solar Cell: Dong-Ho Kang, Sang-Uk Lee, and Nam-Gyu Park; ACS Energy Lett. 2023, 8, 5, 2122–2129 (https://doi.org/10.1021/acsenergylett.3c00568)

Abstract

Methylammonium chloride (MACl) has been used as an additive in a formamidinium lead iodide (FAPbI3) precursor solution for high-efficiency perovskite solar cells (PCSs), where the chloride ion is known to have a positive effect on photovoltaic performance. However, we have found that the residual chloride in the perovskite film has an adverse effect on the device stability. Here, we report an improved stability of PSCs by elimination of residual chloride via postheat-treatment (PHT). Removal of the residual MACl on the perovskite grain surface is accompanied by conversion of surface FAPbI3 to PbI2. Compared with the control perovskite film, the PHT-induced perovskite film shows a longer charge carrier lifetime, which is responsible for an increase in the reverse scanned power conversion efficiency from 21.17% to 23.20%. Moreover, long-term stability tested under humid air conditions for over 1000 h shows that the chloride-removed perovskite film is much more stable than the control film with residual chloride.

Investigating the Effect of Nonideal Conditions on the Performance of a Planar Sb2Se3-Based Solar Cell through SCAPS-1D Simulation: Shahariar Chowdhury, Asmaa Soheil Najm, Montri Luengchavanon, Araa Mebdir Holi, Chin Hua Chia, kuaanan Techato, Sittiporn Channumsin, and Issam K. Salih;  Energy Fuels 2023, 37, 9, 6722–6732 (https://doi.org/10.1021/acs.energyfuels.2c03593)

Abstract

For many years, scientists have wrestled with the disparity between solar cell modeling and real results. Especially, simplified assumptions fabricated by simulation programers can be the best normal reason for this report. However, by using certain nonideal conditions, the simulated solar cell may mimic real conditions in some modeling programs. Using the SCAPS-1D (SCAPS = Solar Cell Capacitance Simulator) program, we endeavored to simulate the representative FTO/TiO2/Sb2Se3/spiro-OMeTAD/Au antimony chalcogenide solar cell (spiro-OMeTAD = 2,2′,7,7′-tetrakis-[N,N-di-(p-methoxyphenyl)amino]-9,9′-spirobifluorene) while accounting for resistance pathways and recombination processes (radiative and Auger). To achieve this, the power of each nonideal condition was prosperously studied. The proficiency results of the investigated solar cell revealed a remarkable variation between the device’s efficiency before and after applying these conditions, ranging from 25% to more than 8.40%. Significant reduction in the efficiency can be attributed to the radiative recombination of the solar cell (active layer). In order to maximize each critical characteristic of the active layers, the influence of the previously ascribed parameters, comprising the doping density and inclusive thickness, was studied with regard to efficiency and integration plots. During the simulation phase, this investigation was novel in that it approximated the outcomes of the aforementioned experimental investigations under nonideal circumstances. Furthermore, employing recombination plots considerably assisted in selecting the appropriate layer characteristic, such as doping density. After adjusting each of the aforementioned settings, the efficiency increased by approximately 4% and a power conversion efficiency of approximately 29% was accomplished. Overall, the results revealed that despite a remarkable drop in cell execution, the simulated cell was more representative of actual conditions and provided a more accurate model for a solar cell.

Review and Perspectives on Advanced Binder Designs Incorporating Multifunctionalities for Lithium–Sulfur Batteries: Sreekala Kunhi Kannan, Jithu Joseph, and Mary Gladis Joseph;  Energy Fuels 2023, 37, 9, 6302–6322 (https://doi.org/10.1021/acs.energyfuels.3c00155)

Abstract

Lithium–sulfur (Li–S) batteries have received paramount attention as a next-generation energy storage device due to their remarkably high specific capacity (1675 mAh g–1), energy density (2600 Wh kg–1), and cost-effectiveness compared to the forefront lithium-ion batteries. However, certain issues still hamper the smooth working of Li–S batteries, which need to be addressed to fill the gap between fundamental research and commercialization. Polymer binders, as an inevitable part of the cathode structure, play a vital role in upholding the structural robustness and firmness of the electrode. However, conventional binders like PVDF are not capable of effectively accommodating the large volume changes within the electrode, facilitating electronic/ionic conductivity, entrapping the soluble polysulfide intermediates, and enhancing polysulfide redox kinetics. Therefore, novel multifunctional binder designs are adopted in Li–S batteries to tackle the above-mentioned issues. This review summarizes the recent progress in this research area employing advanced multifunctional polymer binders in Li–S batteries. The action of the binder through various mechanisms is discussed in detail. The role of binder is given immense attention in the emerging field of various energy storage devices, including Li–S batteries, and, thus, here discussed as well.