Multifunctional Electrochromic Devices for Energy Applications: Suchita Kandpal, Tanushree Ghosh, Chanchal Rani, Anjali Chaudhary, Jinwoo Park, Pooi See Lee, and Rajesh Kumar;  ACS Energy Lett. 2023, 8, 4, 1870–1886 (https://doi.org/10.1021/acsenergylett.3c00159)

Abstract

A lot of development in terms of science and technology has taken place to address the increasing energy needs. This demand is expected to increase, especially due to environmental concerns associated with fossil fuels which have led to aggressive research toward energy storage materials and devices. Looking at this emerging trend, devices and materials that can convert, store, and save energy are the need of the hour. Electrochromic devices that assimilate these energy functionalities, along with bias-induced color modulation, are very promising as they not only help in energy conversion and storage but also help in energy saving when used as smart e-curtains for application in buildings and vehicles. The current Focus Review describes the promise of multifunctional electrochromic devices which can convert/generate and store energy through operations similar to batteries and supercapacitors. It also explains how electrochromism can prove to be a breakthrough in energy-related areas along with key challenges.

Towards Commercialization of Graphite as an Anode for Na-ion Batteries: Evolution, Virtues, and Snags of Solvent Cointercalation: Krishnan Subramanyan and Vanchiappan Aravindan;  ACS Energy Lett. 2023, 8, 1, 436–446 (https://doi.org/10.1021/acsenergylett.2c02295)

Abstract

Sodium-ion storage in graphite through a solvent cointercalation mechanism is extremely robust regarding cycling stability, rate performance, and Coulombic efficiency. The graphite half cell has a low working voltage and high power density. The respectable capacity, even at high current rates, makes graphite in a glyme-based system a versatile energy storage device. This perspective comprehensively looks at graphite-based sodium-ion full cells and how they perform. Electrolyte composition, cathode working voltage, irreversibility, precycling, and high current performance are the key points to consider during full-cell fabrication. Some general factors to consider during the full-cell assembly are put forward in this perspective.

Photo-Rechargeable Li-Ion Batteries: Device Configurations, Mechanisms, and Materials: Akshaykumar D. Salunke, Shubham Chamola, Angus Mathieson, Buddha Deka Boruah, Michael de Volder, and Shahab Ahmad; ACS Appl. Energy Mater. 2022, 5, 7, 7891–7912 (https://doi.org/10.1021/acsaem.2c01109)

Abstract

The development of high-performance solar cells combined with rechargeable batteries is crucial in achieving a sustainable and renewable-based energy future. Photo-Rechargeable batteries (PRBs) are emerging dual-functionality devices, able to both harvest solar energy and store it in the form of electrochemical energy. Recently, efforts have been made in the search for advanced functional materials and integrated device configurations to improve the performance of photoenhanced batteries. A photo-rechargeable battery will provide a unique, standalone energy solution for self-powered remote electronic devices, independent of power grids. However, these devices currently suffer from several technical shortcomings in terms of efficiency, lifetime, and operating voltage. In this review, we present a comprehensive report on the significant research developments in the field of photo-rechargeable Li-ion batteries (Li-PRBs), including device configurations, working mechanisms, material selection, and future directions.

Understanding the Design of Cathode Materials for Na-Ion Batteries: Priyanka Gupta, Sujatha Pushpakanth, M. Ali Haider, and Suddhasatwa Basu; ACS Omega 2022, 7, 7, 5605–5614 (https://doi.org/10.1021/acsomega.1c05794)

Abstract

With the escalating demand for sustainable energy sources, the sodium-ion batteries (SIBs) appear as a pragmatic option to develop large energy storage grid applications in contrast to existing lithium-ion batteries (LIBs) owing to the availability of cheap sodium precursors. Nevertheless, the commercialization of SIBs has not been carried out so far due to the inefficacies of present electrode materials, particularly cathodes. Thus, from a future application perspective, this short review highlights the intrinsic challenges and corresponding strategies for the extensively researched layered transition metal oxides, polyanionic compounds, and Prussian blue analogues. In addition, the commercial feasibility of existing materials considering relevant parameters is also discussed. The insights provided in the current review may serve as an aid in designing efficient cathode materials for state-of-the-art SIBs.

The Perspective of Thermochemical Cycles for Concentrated Solar Energy: Alberto Boretti  and Stefania Castelletto;  ACS Appl. Energy Mater. 2023, 6, 22, 11420–11428 (https://doi.org/10.1021/acsaem.3c01718)

Abstract

The work summarizes the progress of thermochemical cycles to be coupled with a concentrated-solar-power (CSP) technology solar tower with molten salt thermal energy storage. The best perspectives are offered by the sulfur–iodine cycle and the hybrid-sulfur cycle, developed to work at a top temperature of 1000 °C, as permitted in next-generation CSP. The hybrid copper chloride cycle and magnesium chloride cycle are better suited to the current generation of CSP, capped at a top temperature of ∼565 °C. These latter cycles are also suitable for nuclear thermal energy. The research and development needed in all cases is substantial to compensate for the lack of work in recent years.

Reaching the Potential of Ferroelectric Photovoltaics: Marshall B. Frye and Lauren M. Garten;  Acc. Mater. Res. 2023, 4, 11, 906–909 (https://doi.org/10.1021/accountsmr.3c00175)

Introduction

The power conversion efficiency (PCE) of ferroelectric photovoltaics (FePvs) was originally not expected to surpass 0.01%, (1) but since FePv efficiencies now exceed this limit by nearly 3 orders of magnitude, FePvs warrant further investigation. Ferroelectricity occurs exclusively in materials with a polar crystal structure where the spontaneous polarization can be reoriented with an applied electric field. In FePvs light absorption and charge separation occur within a single layer of a ferroelectric material as opposed to p–n junction solar cells. Additionally, FePvs can work without rectification or charge selective contacts, making the photoresponse and device structure significantly different from junction based solar cells. Another unique feature of ferroelectric photovoltaics is that, unlike p-n based solar cells, the photovoltage of FePvs is not limited by the material’s bandgap (Eg); open circuit voltages (VOC) as large as 1600 V have been measured in LiNbO3. (2) Schematics of the photoresponse and FePv device architecture are shown in Figure 1 and compared to a junction based solar cell.

Computational Discovery of Thermochemical Heat Storage Materials Based on Chalcogenide and Complex Anion Salt Hydrates: Steven Kiyabu and Donald J. Siegel;  ACS Appl. Eng. Mater. 2023, 1, 10, 2614–2625 (https://doi.org/10.1021/acsaenm.3c00392)

Abstract

Technologies for thermal energy storage (TES) are limited by the performance of the heat storage material. Therefore, it is desirable to develop materials with superior heat storage properties. The present study employs first-principles calculations to predict the properties of 7012 hypothetical hydrates based on chalcogenide and complex anion salts. Accounting for thermodynamic stability and energy densities, promising hydrates were identified for temperatures below 200 °C, including Li2S·9H2O, Ca(OH)2·8H2O, and Li2CO3·10H2O. System-level projections indicate that several of the proposed materials surpass the energy densities of known materials when incorporated into a solar-thermal storage system. Interpretable machine learning models were trained on the hydrate data set and used to identify features that control the enthalpy of dehydration. This analysis reveals similarities and differences in the thermodynamic behavior of hydrates based on chalcogenides, complex anions, and the previously studied halides. Hydrates based on chalcogenide anions exhibit a wide distribution of dehydration enthalpies; the low average enthalpies of these hydrates reflect the fact that relatively few are stable. In contrast, hydrates based on complex anions and halides exhibit enthalpies that are, on average, larger and more narrowly distributed. The enthalpies of the chalcogenide hydrates can be predicted by using only two machine-learned features, both of which implicate the electronegativity of the cation as a controlling property. This correlation agrees with a trend reported previously for halide-salt hydrates. In contrast, the behavior of the complex-anion hydrates requires twice as many features for machine-learning predictions, and some of these features are complex. Nevertheless, a combination of the molar volume and boiling point data is identified as a useful descriptor. In total, the hydrate compositions and design insights identified in this study are anticipated to catalyze the development of more efficient TES systems.

Intermetallic FeSb2 in a Multifunctional Role of Highly Selective and Efficient Adsorbent, Catalyst, and HER Electrocatalyst: Deepak Gujjar, Sunidhi Gujjar, and Hem C. Kandpal;  ACS Appl. Eng. Mater. 2023, 1, 10, 2626–2634 (https://doi.org/10.1021/acsaenm.3c00394)

Abstract

Developing a low-cost, eco-friendly, and stable material that can efficiently and single-handedly combat two of today’s major problems, the energy and drinking water crisis, is the biggest challenge for the research community. To this end, we present new developments of multifunctional and highly stable intermetallic FeSb2 in three categories: adsorbent, catalyst, and self-supported HER electrocatalyst. FeSb2 particles were synthesized using the coprecipitation method and were found to be highly effective in the adsorptive removal of Congo red (CR) dye, followed by catalytic degradation into less toxic and useful naphthalene and biphenyl derivatives. For electrocatalytic studies, a FeSb2 working electrode with a density greater than 95% was fabricated by the spark plasma sintering process. Remarkably, the FeSb2 electrode generates a geometric current density of −10 mA cm–2 with an overpotential as low as 58 mV and exhibits a Tafel slope of 54.9 mV/dec compared to the benchmark Pt/C catalyst. A strong boost in electrocatalytic activity was found after chronoamperometry testing for 5 h. Overall, this study proves FeSb2 to be a promising and potential electrocatalyst for hydrogen production and an adsorbent cocatalyst for the removal and degradation of CR dye.

Hydrogen/Syngas Production from Different Types of Waste Plastics Using a Sacrificial Tire Char Catalyst via Pyrolysis–Catalytic Steam Reforming: Yukun Li, Mohamad A. Nahil, and Paul T. Williams; Energy Fuels 2023, 37, 9, 6661–6673 (https://doi.org/10.1021/acs.energyfuels.3c00499)

Abstract

Single plastics and mixed waste plastics from different industrial and commercial sectors have been investigated in relation to the production of hydrogen and syngas using a pyrolysis–catalytic steam reforming process. The catalyst used was a carbonaceous char catalyst produced from the pyrolysis of waste tires. Total gas yields from the processing of single plastics were between 36.84 and 39.08 wt % (based on the input of plastic, reacted steam, and char gasification) but those in terms of the gas yield based only on the mass of plastic used were very high. For example, for low-density polyethylene (LDPE) processing at a catalyst temperature of 1000 °C, the gas yield was 445.07 wt % since both the reforming of the plastic and also the steam gasification of the char contributed to the gas yield. The product gas was largely composed of H2 and CO, i.e., syngas (∼80 vol %), and the yield was significantly increased as the char catalyst temperature was raised from 900 to 1000 °C. Hydrogen yields for the processing of the polyolefin single plastics were ∼130 mmol gplastic–1 at a catalyst temperature of 1000 °C. The pyrolysis–catalytic steam reforming of the industrial and commercial mixed plastics with the tire char catalyst produced hydrogen yields that ranged from 92.81 to 122.6 mmol gplastic–1 and was dependent on the compositional fraction of the individual plastics in their mixtures. The tire char catalyst in the process acted as both a catalyst for the steam reforming of the plastics pyrolysis volatiles to produce hydrogen and also as a reactant (“sacrificed”), via carbon-steam gasification to produce further hydrogen.

Hydrogen Generation from the Wastewater of Power Plants via an Integrated Photovoltaic and Electrolyzer System: A Pilot-Scale Study: Seyedhassan Fakourian and Mahsa Alizadeh;  Energy Fuels 2023, 37, 8, 6099–6109 (https://doi.org/10.1021/acs.energyfuels.3c00186)

Abstract

This study presents the first work that investigates a preliminary design generating hydrogen from the wastewater of coal utility boilers via an integrated photovoltaic (PV)–electrolysis system. Connecting solar panels, which generates electricity, to an electrolyzer to split water molecules to hydrogen and oxygen is an attractive method to generate hydrogen. A numerical model is developed for the integrated PV solar panels and polymer electrolyte membrane (PEM) electrolyzer. Parallel solar panels and series PEM electrolyzer cells are considered in the present work to reach the optimum arrangement. The essential losses including the activation and ohmic overpotentials and the required energy for rotary equipment (compressors and pumps) are considered in the model. The effect of the working temperature, solar irradiation, and charge transfer coefficient on the efficiency of the system is investigated. The calculated efficiency of the PEM electrolyzer and PV solar panels is in the range of 60–62.5% and 18–20%, respectively. The efficiency of the integrated PV electrolyzer increases as solar irradiation increases. Of particular interest is the potential application of the present design in Texas, which generates 1.43 × 104 Nm3/year of green hydrogen for $4.67/kg H2 by only scaling up by 11. This model provides valuable insights for the large-scale hydrogen generation from power plants’ wastewater via the coupled solar energy and electrolysis system.

In Situ Selenization of Ti3C2Tx Assisted by Cu2+ with Superior Performance for Aluminum Ion Batteries: Lu Qin, Jianjian Zhong, and Jianling Li; Energy Fuels 2023, 37, 8, 6220–6229 (https://doi.org/10.1021/acs.energyfuels.3c00323)

Abstract

A prominent topic in related fields is the search for cathode materials for aluminum-ion batteries (AIBs) with high specific capacity and outstanding cycle performance. MXenes, a two-dimensional layered material, can be used for a variety of energy storage purposes. However, their application in AIBs is hampered by poor capacity and significant self-accumulation. In this study, we employ a simple two-step process, first electrostatically adsorbing Cu2+ on MXenes and then in situ selenizing MXenes layers to produce TiSe2. The composite product F-Ti3C2Tx@Cu@TiSe2 exhibits an initial discharge specific capacity of 360.3 mAh g–1, and the capacity remains at 267.5 mAh g–1 after 100 cycles. In contrast, the directly selenized F-Ti3C2Tx@TiSe2 without Cu2+ shows a capacity of just 77.2 mAh g–1 after 100 cycles. This huge improvement is due to the fact that the electrostatic adsorption of Cu2+ on MXenes induces polarized sites with high electron density and optimizes the spatial structure of MXenes. This phenomenon effectively alleviates self-accumulation, providing a larger specific surface area and making it easier for [AlCl4]− to embed and escape. Through the X-ray photoelectron spectroscopy test and charge and discharge curves, it is found that the main capacity of the material comes from the redox reaction of [AlCl4]− and selenides in AIBs. Herein, the utilization of Cu2+ adsorbed MXenes as precursors followed by in situ selenization is innovative and also validates the great potential of Cu2+ adsorption in the field of electrochemistry.

Reducing Energy Loss in Polymer Solar Cell through Optimization of Novel Metal Nanocomposite: Mohammed S. G. Hamed, Jude N. Ike, Yilin Wang, Ke Zhou, Wei Ma, and Genene Tessema Mola; Energy Fuels 2023, 37, 8, 6129–6137 (https://doi.org/10.1021/acs.energyfuels.3c00531)

Abstract

Ag/CuPO4 nanocomposite was successfully synthesized using wet chemistry for potential application as a mechanism to suppress charge recombination and harvest more photons in thin-film organic solar cells (TFOSCs). The morphological and optical properties of the nanocomposite were studied using high-resolution electron microscopy and UV–vis spectroscopy. The Ag/CuPO4 nanocomposite exhibited a semispherical geometry which is suitable for the occurrence of localized surface plasmon resonance (LSPR) and light scattering in a dielectric medium. Conventional device architecture is employed that uses a solar absorber composed of a poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend with and without the nanocomposite. As a result, significant changes in the device performances were observed by the incorporation of the metal nanocomposite, where the experimental evidence suggested that the doped active layer outperformed the undoped ones. Consequently, the best power conversion efficiency (PCE) grew by nearly 95% compared to the reference cell. Furthermore, the measured photocurrents are found to be dependent on the concentration of the nanocomposite in the absorber layer. In this article, the effects of metal nanocomposite are discussed in terms of the phenomena of local surface plasmon resonance and far-field scattering in the photoactive medium of TFOSCs.

A Lithium–Sulfur Battery Using Binder-Free Graphene-Coated Aluminum Current Collector: Wolfgang Brehm, Vittorio Marangon, Jaya Panda, Sanjay B. Thorat, Antonio Esaú del Rio Castillo, Francesco Bonaccorso, Vittorio Pellegrini, and Jusef Hassoun;  Energy Fuels 2022, 36, 16, 9321–9328 (https://doi.org/10.1021/acs.energyfuels.2c02086)

Abstract

Lithium–sulfur battery of practical interest requires thin-layer support to achieve acceptable volumetric energy density. However, the typical aluminum current collector of Li-ion battery cannot be efficiently used in the Li/S system due to the insulating nature of sulfur and a reaction mechanism involving electrodeposition of dissolved polysulfides. We study the electrochemical behavior of a Li/S battery using a carbon-coated Al current collector in which the low thickness, the high electronic conductivity, and, at the same time, the host ability for the reaction products are allowed by a binder-free few-layer graphene (FLG) substrate. The FLG enables a sulfur electrode having a thickness below 100 μm, fast kinetics, low impedance, and an initial capacity of 1000 mAh gS–1 with over 70% retention after 300 cycles. The Li/S cell using FLG shows volumetric and gravimetric energy densities of 300 Wh L–1 and 500 Wh kg–1, respectively, which are values well competing with commercially available Li-ion batteries.

Advances in Selenium Sulfides Cathodes for Lithium/Selenium–Sulfur Batteries: Zhenkai Zhou, Xiaomei Huo, Yuhang Liu, Siying Wang, Wanqing Guan, Zhuzhu Du, and Wei Ai; ACS Appl. Eng. Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaenm.3c00587)

Abstract

The global energy crisis has sparked extensive research into rechargeable battery materials to address the growing demand for energy. High-capacity electrode materials are central to achieving significant advances in energy density. Lithium/selenium–sulfur (LSeSBs) batteries have emerged as an exciting alternative to lithium–sulfur and lithium–selenium systems, harnessing the combined benefits of sulfur’s high capacity and selenium’s enhanced electrical conductivity. This integration has established selenium sulfides (SexSy) as an encouraging category of cathode substances. Recent years have seen a flurry of research, yielding significant findings in this domain. This review encapsulates the current state of LSeSBs battery research with a particular focus on pioneering work in SexSy cathode materials. It delves into the reaction mechanism and factors contributing to capacity decay, examining the relationship between performance and structure across various cathode configurations, including different Se/S ratios and a multitude of hosts of carbons, conducting polymers, and doped carbons. This review sheds light on the complex relationships between the ratios of selenium and sulfur in SexSy cathodes, their respective strengths and weaknesses, and innovative engineering solutions that contribute to the performance of LSeSBs.

Polymer-Derived Silicon Carbide and Boron Nitride Nanotube Composites with High Thermal Shock Resistance: Haoran Li, Leila Shahriari, Yash Khandwani, Samuel Talevich, Aspen Reyes, Rebekah Sweat, Keyou Mao, Lyndsey R. Scammell, R. Roy Whitney, Jin Gyu Park, Qiang Wu, Zhiyong Liang, and Zhibin Yu;  ACS Appl. Eng. Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaenm.3c00524)

Abstract

Ceramic composite manufacturing typically requires high temperatures and a long duration of sintering or pyrolysis and has a low yield. Efforts to accelerate manufacturing, especially in the case of emerging polymer-derived ceramics, can result in void and crack formation or even catastrophic failure of the ceramic product. Research findings reveal that boron nitride nanotube networks effectively reinforce polymer-derived silicon carbide ceramics, enabling them to withstand substantial volume changes during pyrolysis. This reinforcement results in the production of high-quality ceramics characterized by extremely low porosity and enhanced mechanical and thermal properties, encompassing improvements in the elastic modulus, fracture strength, ductility, and thermal shock resistance. No degradation of mechanical properties was observed after 100 thermal shock cycles with a sudden temperature drop of about 1100 °C at a rate of about 2190 °C s–1. By increasing the nanotube weight concentration to 40%, highly flexible ceramic thin films were obtained that can be bent to a small radius without failure. With the addition of nanotubes, pyrolysis can also proceed with a much faster temperature ramping rate for both heating and cooling cycles, enabling much faster manufacturing throughput than conventional pyrolysis for dense-structure ceramics.

Fabrication and Thermal Properties of a Gallium and Porous Foam Composite Phase Change Material: Rachel C. McAfee, Michael C. Fish, Adam A. Wilson, Harvey H. Tsang, Jonathan A. Boltersdorf, Soonwook Kim, Nenad Miljkovic, and William P. King;  ACS Appl. Eng. Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaenm.3c00366)

Abstract

A thermal energy storage composite is fabricated by infiltrating liquid metal gallium (Tm = 30.76 ± 0.3 °C) into an open-cell porous nickel foam (dp ≈ 0.25 mm, porosity 95%). Sample preparation and process refinement lead to a reduction in material voiding to an observed 2.4 ± 0.84% volume fraction while remaining fabricable with common benchtop laboratory equipment. Comprehensive infiltration results in a measured thermal conductivity of 39.1 ± 2.9 W/m-K at 75 °C with the gallium fraction in liquid state, owing to the enhancement effect of the conductive nickel lattice. Gravimetric latent heat of melting is reduced in rough proportion to the mass fraction of nickel and measured at 72.56 ± 0.18 J/g. Taken together, these properties represent a best-in-class performance among near-room temperature phase change materials (Tm < 100 °C) according to power density figure of merit. Furthermore, retention in the high-surface area foam network through capillary effects precludes the need for elaborate liquid confinement during application insertion and mitigates the degree of supercooling upon solidification (observed in ∼100 mg composite samples as ΔTsub: 25–40 °C vs pure samples ΔTsub: 50–60 °C).

Vanadium-Doped Induction of Bare Active Crystalline Planes of Tungsten Oxide and Its Excellent Anticorrosion Properties: Zi-Xiang Liu, Dan Zhou, Jing-Jing Tian, and Jin-Ku Liu;  ACS Appl. Eng. Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaenm.3c00437)

Abstract

The “pinning effect” of VO2 was used to expose the (110) crystalline plane of WO3 monoclinic phase to explore the contribution of the high-energy crystalline plane to the electrochemical performance of the vanadium–tungsten (VW) complexes. The characterizations of the prepared sample were done by XRD, SEM, and EDS. The impedance value of VW2 (VO2/WO3) was improved by 8730 ohm·cm2 over epoxy resin, thereby showing the best anticorrosion effect. The reason for the enhanced corrosion inhibition of the VW material was that the highly active (110) crystalline plane gave higher activity to the oxygen defects, which was conducive to the formation of hydroxyl groups by adsorption of H2O and O2. At the same time, electrochemical cathodic reaction was inhibited. Second, the active hydroxyl group on the plane of the (110) high-energy crystal plane formed hydrogen bonds with epoxy resin, which not only improved the interaction between corrosion inhibitor and epoxy resin but also resulted in the emergence of intercalated lamellar insoluble hydroxide, which improved the shielding property of the coating. Third, the reduction protection brought by the V4+ ion led to the advancement of the corrosion resistance of the VW2 complexes. The present study completed the research system of tungsten oxide, which was of guidance for the control of the crystal plane and the design of anticorrosion pigments.

Unveiling the Synergistic Effect of Magnetite and ZrPO4 for Highly Selective Removal of Anionic Azo Dyes via an Ion-Exchange Process: Sangita Kumari Swain, Anupam Sahoo, Sumanta Kumar Majhi, Ganngam Phaomei, Naba Kishore Sahoo, and Sukanta Kumar Tripathy;  ACS Appl. Eng. Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaenm.3c00492)

Abstract

This work represents a facile process based on ion exchange for the efficient removal of toxic and carcinogenic anionic azo dyes from industrial effluents. Azo dyes pose significant environmental challenges due to their high solubility and stability in water bodies. For this purpose, a magnetically retrievable nanocomposite Fe3O4/ZrPO4 (FZ) has been designed. The FZ nanocomposite, consisting of nano zirconium phosphate (ZrPO4) supported on magnetite nanoparticles (Fe3O4 NPs), demonstrates synergistic interaction between the ion-exchange properties of ZrPO4 and the magnetic properties of Fe3O4, leading to improved selectivity and recyclability for the removal of anionic azo dye. Characterization of the synthesized FZ nanocomposites was carried out by using X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The removal efficiency of FZ has been verified by taking reactive azo dyes including congo red (CR), reactive blue 1 (RB-1), reactive orange 16 (RO-16), and reactive violet 5 (RV-5). The reported nanocatalyst exhibits impressive adsorption capabilities, removing around 99% for CR and RB-1, 97% for RO-16, and 78% for RV-5 within 5 min in an acidic medium. The nanocomposite’s magnetic property allows efficient separation from reaction mixtures, and the ion-exchange property enables its reusability for more than 15 catalytic cycles. Further, optimization of the pH of the reaction medium resulted in faster, cost-effective, more efficient separation and regeneration of the nanocomposites. The industrial applicability of this nanocomposite has been verified by treatment with synthetic wastewater. The findings hold promise for addressing environmental concerns associated with azo dye contamination in industrial effluents.

Graphitized Mesoporous Engineered Carbon Support for Fuel Cell Applications: Nagappan Ramaswamy, Barr Zulevi, Geoff McCool, Zixiao Shi, Aldo Chavez, David A. Muller, Anusorn Kongkanand, and Swami Kumaraguru;  ACS Appl. Eng. Mater. 2023, 1, 10, 2543–2554 (https://doi.org/10.1021/acsaenm.3c00354)

Abstract

As proton exchange membrane fuel cells mature into commercial devices capable of powering a wide range of stationary and automotive applications, they need materials with tunable properties to improve their performance and durability. Carbon supports used for platinum (Pt) nanoparticle dispersion is typically based on a furnace black-type material with a random structure, thereby hindering progress in catalyst development. To address this challenge, engineered carbons with a tunable mesoporous structure offer an opportunity to maximize catalyst performance and durability. In this article, we report on the development of a graphitized, mesoporous carbon support with a high degree of ordering, labeled here as ECS4005, for the dispersion of Pt nanoparticles. Pt/ECS4005 shows significantly improved kinetic activity due to its mesoporous structure that mitigates Pt poisoning by sulfonate functional groups in the ionomer while simultaneously enabling favorable accessibility to reactants.

What Is the Rate-Limiting Step of Oxygen Reduction Reaction on Fe–N–C Catalysts?: Saerom Yu, Zachary Levell, Zhou Jiang, Xunhua Zhao, and Yuanyue Liu;  J. Am. Chem. Soc. 2023, 145, 46, 25352–25356 (https://doi.org/10.1021/jacs.3c09193)

Abstract

Oxygen reduction reaction (ORR) is essential to various renewable energy technologies. An important catalyst for ORR is single iron atoms embedded in nitrogen-doped graphene (Fe–N–C). However, the rate-limiting step of the ORR on Fe–N–C is unknown, significantly impeding understanding and improvement. Here, we report the activation energies of all of the steps, calculated by ab initio molecular dynamics simulations under constant electrode potential. In contrast to the common belief that a hydrogenation step limits the reaction rate, we find that the rate-limiting step is oxygen molecule replacing adsorbed water on Fe. This occurs through concerted motion of H2O desorption and O2 adsorption, without leaving the site bare. Interestingly, despite being an apparent “thermal” process that is often considered to be potential-independent, the barrier reduces with the electrode potential. This can be explained by stronger Fe–O2 binding and weaker Fe–H2O binding at a lower potential, due to O2 gaining electrons and H2O donating electrons to the catalyst. Our study offers new insights into the ORR on Fe–N–C and highlights the importance of kinetic studies in heterogeneous electrochemistry.

Rechargeable Hydrogen–Chlorine Battery Operates in a Wide Temperature Range: Zehui Xie, Zhengxin Zhu, Muhammad Sajid, Na Chen, Mingming Wang, Yahan Meng, Qia Peng, Shuang Liu, Weiping Wang, Taoli Jiang, Kai Zhang, and Wei Chen;  J. Am. Chem. Soc. 2023, 145, 46, 25422–25430 (https://doi.org/10.1021/jacs.3c09819)

Abstract

Hydrogen–chlorine (H2–Cl2) fuel cells have distinct merits due to fast electrochemical kinetics but are afflicted by high cost, low efficiency, and poor reversibility. The development of a rechargeable H2–Cl2 battery is highly desirable yet challenging. Here, we report a rechargeable H2–Cl2 battery operating statically in a wide temperature ranging from −70 to 40 °C, which is enabled by a reversible Cl2/Cl– redox cathode and an electrocatalytic H2 anode. A hierarchically porous carbon cathode is designed to achieve effective Cl2 gas confinement and activate the discharge plateau of Cl2/Cl– redox at room temperature, with a discharge plateau at ∼1.15 V and steady cycling for over 500 cycles without capacity decay. Furthermore, the battery operation at an ultralow temperature is successfully achieved in a phosphoric acid-based antifreezing electrolyte, with a reversible discharge capacity of 282 mAh g–1 provided by the highly porous carbon at −70 °C and an average Coulombic efficiency of 91% for more than 300 cycles at −40 °C. This work offers a new strategy to enhance the reversibility of aqueous chlorine batteries for energy storage applications in a wide temperature range.

Enhancing Biomethane Production from OFMSW: The Role of Moderate Temperature Thermal Pretreatment in Anaerobic Digestion: Masoud Kamali, Reza Abdi, Abbas Rohani, Shamsollah Abdollahpour, and Sirous Ebrahimi;  Ind. Eng. Chem. Res. 2023, 62, 46, 19471–19481 (https://doi.org/10.1021/acs.iecr.3c02931)

Abstract

This study investigates the effect of moderate temperature thermal pretreatment on the high-solid anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) for enhanced methane production and energy recovery. Batch biomethane potential (BMP) assays were conducted under mesophilic conditions, with pretreatment temperatures of 70, 90, and 110 °C for durations of 30, 75, 120, and 180 min. A completely randomized factorial experiment was utilized to evaluate the effects of each temperature and time of pretreatment as well as their interactions on methane yield. The evaluation criteria included methane enhancement and net energy generation (NEG). While all thermal pretreatments led to an increased methane yield, energy balance analysis revealed that only certain pretreatments were effective in contributing to a positive energy balance. The best result was achieved by applying pretreatment at 90 °C for 120 min, which resulted in a 34% increase in methane production compared to untreated OFMSW, with a specific methane production of 342.66 ± 6.11 mL CH4/g VS. Applying this thermal pretreatment also resulted in a net energy generation of 57.26 KWh/ton. These findings suggest that moderate temperature thermal pretreatment can be an effective method for enhancing biogas production and energy recovery from OFMSW AD under high-solid conditions.

Probing the Performance of a Ni–Ca–Ce Dual-Functional Material for Integrated CO2 Capture and Utilization from a Synthetic Flue Gas Approximating Industrial Composition: Lukas C. Buelens, Louis Van de Voorde, Varun Singh, Hilde Poelman, Guy B. Marin, and Vladimir V. Galvita;  Ind. Eng. Chem. Res. 2023, 62, 46, 19559–19570 (https://doi.org/10.1021/acs.iecr.3c02459)

Abstract

Confining CO2 emissions and accelerating toward a circular carbon economy demand process intensification strategies. This work evaluates integrated CO2 capture and catalytic conversion over a solid dual-functional material (DFM) in the presence of H2O and O2, approximating industrial compositions in a laboratory-scale fixed-bed reactor. CO2 from flue gas and its isothermal utilization with H2 are temporally separated by applying chemical looping with isolated steps driven by CaO and Ni. A ceria-modified DFM shows over 60% CO2 capture efficiency and 70% CO2 conversion with average space-time yields exceeding 850 kgCO2 m–3reactor h–1 and 300 kgCO m–3reactor h–1 at 973 K and 120 kPa. Increasing the H2 feed concentration during the CO2 utilization step steers the selectivity toward CH4. The material maintains its performance over 30 cycles using a synthetic flue gas containing CO2, O2, and H2O and 75 mol % H2 for the CO2 capture and utilization steps.

Investigation of Ethylisopropyl Sulfone Medium with a Copper-Based Redox Electrolyte for Ambient Light Dye-Sensitized Solar Cells: Achieving High Efficiency and Enduring Long-Term Stability: Daniela Sayah and Tarek H. Ghaddar; ACS Appl. Energy Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaem.3c02067)

Abstract

In recent years, dye-sensitized solar cells (DSCs) have shown remarkable efficiency levels, particularly under low light conditions, making them promising candidates for indoor applications. However, for these devices to be successfully commercialized, high power conversion efficiencies (PCEs) alone are not sufficient. Long-term stability is a critical aspect that needs to be addressed. Most of the well performing DSCs reported so far have utilized conventional organic solvents, which have low boiling points and are highly volatile. While these solvents contribute to achieving high PCE values, they are prone to leakage and evaporation, limiting the long-term stability of the devices. Herein, we report on cosensitized DSC devices (A–E) with commercial dyes (XY1b/MS5) and different additives. This was accomplished by employing for the first time ethylisopropyl sulfone (EiPS) as a high boiling point solvent along with Cu(I)(dmby)2·TFMSI and Cu(II)(dmby)2Cl·TFMSI as the redox mediators in DSCs. Remarkably, most of the tested DSC devices exhibited exceptional performance, achieving high PCE values ranging from 19% to 23% under 1000 lx irradiation and up to 0.82% under 1 sun simulated solar light irradiation. Our analysis revealed that the N-methylbenzimidazole (NMBI) additive played a crucial role in ensuring both good PCE% and long-lasting durability, particularly in device B. On the other hand, the use of additives such as 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (ImTFMSI) and/or LiTFMSI resulted in deterioration of the photovoltaic parameters during the long-term stability tests in the EiPS-based electrolyte medium, observed in devices C–E. This knowledge opens up possibilities for further optimization of ambient-light DSCs with improved stability and provides a viable solution for indoor power generation applications.

High-Performance Copper/Copper Oxide-Based Cathode Prepared by a Facile Ball-Milling Method for All-Solid-State Fluoride-Ion Batteries: Zulai Cao, Kentaro Yamamoto, Datong Zhang, Toshiyuki Matsunaga, Mukesh Kumar, Neha Thakur, Toshiki Watanabe, Hidenori Miki, Hideki Iba, Koji Amezawa, and Yoshiharu Uchimoto;  ACS Appl. Energy Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaem.3c02003)

Abstract

Benefiting from the high theoretical volumetric energy density of the metal/metal fluoride (M/MFx) cathodes, all-solid-state fluoride-ion batteries (FIBs) are anticipated to be one of the next-generation energy storage devices. However, M/MFx electrodes have low rate capability due to the large diffusion overpotential of fluoride ions because the reaction proceeds by a two-phase reaction mechanism between the metal M phase and the metal fluoride MFx phase, which has significantly different lattice constants. To address this problem, uniformly distributed nanoparticles should be designed to shorten the diffusion pathway. Herein, we report a facile ball-milling method for preparing Cu-based cathode materials. Our findings reveal that as the ball-milling rotation speed increases, there is a significant decrease in the crystallite size of the solid electrolyte and a transformation of Cu oxides into metallic Cu, accompanied by an increase in the crystallite size. Among the as-prepared cathode composites, a fine mixture of metallic Cu and Cu oxides with intermediate rotation speed (300 rpm) exhibits superior electrochemical performance, with a reversible capacity of 400 mAh gCu2O–1 after 20 cycles. Furthermore, it exhibits excellent rate capability by combining the high capacity of Cu with the satisfactory rate performance of Cu2O, achieving a capacity of 174 mAh gCu2O–1 at a current density of 550 mA gCu2O–1, which is currently the highest reported for Cu-based cathode materials in FIBs. A charge compensation mechanism involving Cu0/Cu2+ and Cu/Cu+2+ redox reactions has been confirmed by electrochemical methods, X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and scanning transmission electron microscopy (STEM) measurements. The dominant factors affecting the impedance spectra of the as-prepared composites were also been investigated. It is believed that the cathode composites prepared by a facile ball-milling method in this work will lead to a significant step in the application of all-solid-state FIBs.

Facilitating Sodium Nucleation in Anode-Free Sodium Batteries: Emily R. Cooper, Ming Li, Qingbing Xia, Ian Gentle, and Ruth Knibbe;  ACS Appl. Energy Mater. 2023, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsaem.3c01938)

Abstract

Sodium metal batteries (NMBs) have attracted significant attention as next-generation, high energy density battery technologies. However, NMBs are disadvantaged by the excessive Na metal used as the anode, which decreases energy density and safety. So-called anode-free NMBs, where the anode is electrochemically generated during charging, are a promising solution. However, such batteries are still prone to dendrite growth and capacity fade. In this work, we computationally and experimentally screen a range of metals, including Zn, Cu, and α-brass, as current collectors for anode-free NMBs. Our results show that Zn was the best performing current collector material, inducing small nucleation overpotentials of −16.5 mV and increasing cycling stability up to 200 cycles with an average Coulombic efficiency of 98.9%. We propose this high performance is due to high lattice compatibility between Na and Zn as well as the formation of a favorable ZnF2-rich interphase. This study offers valuable insight into selecting current collectors and engineering the interfacial chemistry to improve the performance of anode-free NMBs.

An Investigation of Conjugated Sulfonamide Materials as Binders for Organic Lithium-Ion Batteries: Jiang Tian Liu, Eloi Grignon, Alicia M. Battaglia, Muhammad Imran, Christopher Copeman, Harrison A. Mills, Ashlee J. Howarth, Edward H. Sargent, and Dwight S. Seferos;  Chem. Mater. 2023, 35, 22, 9692–9701 (https://doi.org/10.1021/acs.chemmater.3c02105)

Abstract

Organic electrode materials have emerged as promising solutions for numerous energy applications. However, their full utility is impeded by their limited stability and inherently poor conductivity. To address these issues, one approach is to use functional conjugated polymers to replace the conventional insulating poly(vinylidene fluoride) (PVDF) binder that may facilitate ion/electron transport and stabilize the electrode. In this study, we report the synthesis of a series of sulfonamide π-conjugated small molecules, linear oligomers, and two-dimensional polymers and their subsequent use as binder materials for organic electrodes. We observe an enhanced specific capacity in a perylenetetracarboxylic dianhydride (PTCDA) composite electrode. The impact of dimensionality is evaluated through the battery performance. The two-dimensional sulfonamide polymer affords a 3-fold improvement in capacity retention compared to PVDF. The results presented in this work highlight that sulfonamide-containing materials are promising candidates as metal ion battery binders and that dimensionality is a key parameter for their use in lithium-ion batteries.

Evolution of Highly Anisotropic Magnetism in the Titanium-Based Kagome Metals LnTi3Bi4 (Ln: La···Gd3+, Eu2+, Yb2+): Brenden R. Ortiz, Hu Miao, David S. Parker, Fazhi Yang, German D. Samolyuk, Eleanor M. Clements, Anil Rajapitamahuni, Turgut Yilmaz, Elio Vescovo, Jiaqiang Yan, Andrew F. May, and Michael A. McGuire;  Chem. Mater. 2023, 35, 22, 9756–9773 (https://doi.org/10.1021/acs.chemmater.3c02289)

Abstract

Here, we present a family of titanium-based kagome metals of the form LnTi3Bi4 (Ln: La···Gd3+, Eu2+, Yb2+). Four previously unreported compounds are presented: YbTi3Bi4, GdTi3Bi4, NdTi3Bi4, and PrTi3Bi4. Single-crystal growth methods are provided alongside detailed magnetic and thermodynamic measurements across the entire series. The LnTi3Bi4 family of compounds are orthorhombic (Fmmm), layered compounds that exhibit slightly distorted titanium-based kagome nets interwoven with zigzag lanthanide-based (Ln) chains. Crystals are easily exfoliated parallel to the kagome sheets, and angular resolved photoemission (ARPES) measurements highlight the intricacy of the electronic structure in these compounds. Density functional theory (DFT) and ARPES studies find Dirac points near the Fermi level, consistent with the kagome-derived band structure. The magnetic properties and the associated anisotropy emerge from the quasi-1D zigzag chains of Ln and impart a wide array of magnetic ground states ranging from anisotropic ferromagnetism to complex antiferromagnetism with a cascade of metamagnetic transitions. The combination of the kagome-based electronic structure and highly anisotropic Ln-based magnetism on an exfoliatable platform cements the LnTi3Bi4 family as an interesting addition to the ever-expanding suite of kagome metals.

High-Performance Dual-Ion Battery Based on a Layered Tin Disulfide Anode: Yao-Bing Fang, Wen Zheng, Tao Hu, Li Li, and Wen-Hui Yuan;  ACS Omega 2022, 7, 9, 7616–7624 (https://doi.org/10.1021/acsomega.1c06134)

Abstract

Energy issues have attracted great concern worldwide. Developing new energy has been the main choice, and the exploitation of the electrochemical energy storage devices plays an important role. Herein, a high-performance dual-ion battery system is proposed, which consists of a graphite cathode and SnS2 anode, with a high-concentration lithium salt electrolyte (4 M LiTFSI). The benefits from the typical sandwich-like layer structure of SnS2 are as follows: the highest discharge specific capacity of the battery could reach 130.0 mA h g–1 at a current density of 100 mA g–1, and even under an ultra-high current density of 2000 mA g–1, the highest capacity of 66.3 mA h g–1 is still achieved, with an outstanding capacity retention over 100% after 1000 cycles. Inspiringly, this system delivers an excellent low self-discharge of 1.19%/h, surpassing most of the reported dual-ion batteries. In addition, the working mechanism and structural stability are also investigated by X-ray diffraction and Raman spectra, indicating a good reversibility. These results reveal that this graphite/SnS2 dual-ion battery system could provide a promising alternative for a future high-performance energy storage device.

Fundamental Insights into Battery Thermal Management and Safety: Ryan S. Longchamps, Xiao-Guang Yang, and Chao-Yang Wang;  ACS Energy Lett. 2022, 7, 3, 1103–1111 (https://doi.org/10.1021/acsenergylett.2c00077)

Abstract

To break away from the trilemma among safety, energy density, and lifetime, we present a new perspective on battery thermal management and safety for electric vehicles. We give a quantitative analysis of the fundamental principles governing each and identify high-temperature battery operation and heat-resistant materials as important directions for future battery research and development to improve safety, reduce degradation, and simplify thermal management systems. We find that heat-resistant batteries are indispensable toward resistance to thermal runaway and therefore ultimately battery safety. Concurrently, heat-resistant batteries give rise to long calendar life when idling at ambient temperatures and greatly simplify thermal management while working, owing to much enlarged temperature difference driving cooling. The fundamentals illustrated here reveal an unconventional approach to the development of current and future battery technologies as society moves toward ubiquitous electrified transportation.

Battery Hazards for Large Energy Storage Systems: Judith A. Jeevarajan, Tapesh Joshi, Mohammad Parhizi, Taina Rauhala, and Daniel Juarez-Robles;  ACS Energy Lett. 2022, 7, 8, 2725–2733 (https://doi.org/10.1021/acsenergylett.2c01400)

Abstract: Energy storage systems (ESSs) offer a practical solution to store energy harnessed from renewable energy sources and provide a cleaner alternative to fossil fuels for power generation by releasing it when required, as electricity. The energy stored and later supplied by ESSs can greatly benefit the energy industry during regular operation and more so during power outages. Electrochemical energy storage has taken a big leap in adoption compared to other ESSs such as mechanical (e.g., flywheel), electrical (e.g., supercapacitor, superconducting magnetic storage), thermal (e.g., latent phase change material), and chemical (e.g., fuel cells) types, thanks to the success of rechargeable batteries. Figure 1 depicts the various components that go into building a battery energy storage system (BESS) that can be a stand-alone ESS or can also use harvested energy from renewable energy sources for charging. The electrochemical cell is the fundamental component in creating a BESS. A module is a set of single cells connected in parallel-series configurations to provide the required battery capacity and voltage. The complete set of modules arranged in racks constitutes a battery. A battery management system (BMS) allows for monitoring and controlling the charge and discharge of the battery. Thermal management of the battery is managed by the heating, ventilation, and air conditioning (HVAC) system that controls the environmental temperature and humidity. Integrating the BESS with renewable energy sources for the charging process can be done directly or through an AC/DC inverter. The BESS battery operates with DC, and renewable energy sources can produce both AC and/or DC current. The DC/AC inverter also enables the BESS to be integrated with the electrical grid by demanding energy when needed or supplying excess energy, as long as the minimum requirements of the grid are met.

Safety and Quality Issues of Counterfeit Lithium-Ion Cells: Tapesh Joshi, Saad Azam, Daniel Juarez-Robles, and Judith A. Jeevarajan;  ACS Energy Lett. 2023, 8, 6, 2831–2839 (https://doi.org/10.1021/acsenergylett.3c00724)

Abstract

Lithium-ion batteries continue to transform consumer electronics, mobility, and energy storage sectors, and the applications and demands for batteries keep growing. Supply limitations and costs may lead to counterfeit cells in the supply chain that could affect quality, safety, and reliability of batteries. Our research included studies of counterfeit and low-quality lithium-ion cells, and our observations on the differences between these and original ones, as well as the significant safety implications, are discussed. The counterfeit cells did not include internal protective devices such as the positive temperature coefficient or current interrupt devices that typically offer protection against external short circuits and overcharge conditions, respectively, in cells from original manufacturers. Poor-quality materials and lack of engineering knowledge were also evident on analyses of the electrodes and separators from low-quality manufacturers. When the low-quality cells were subjected to off-nominal conditions, they experienced high temperature, electrolyte leakage, thermal runaway, and fire. In contrast, the authentic lithium-ion cells performed as expected. Recommendations are provided to identify and avoid counterfeit and low-quality lithium-ion cells and batteries.

A Nonflammable Electrolyte for High-Voltage Lithium Metal Batteries: Guangzhao Zhang, Jiawei Li, Qingrong Wang, Hui Wang, Jun Wang, Kai Yu, Jian Chang, Chaoyang Wang, Xiang Hong, Qiang Ma, and Yonghong Deng;  ACS Energy Lett. 2023, 8, 7, 2868–2877 (https://doi.org/10.1021/acsenergylett.3c00706)

Abstract

The electrochemical instability of the polar solvents in electrolytes often causes reduction/oxidation at the surface of both Li anodes and nickel-rich cathodes in high-voltage lithium metal batteries (LMBs). Here, we design a bipolar molecule-regulated electrolyte with a capsule-like solvation structure and nonflammability to stabilize high-voltage LMBs. The key enabler is to design and synthesize a nonflammable bipolar molecule with a ion-dissociative polar head and a perfluorinated nonpolar tail. The bipolar solvent promotes the formation of capsule-like solvation sheaths via weak coordination and encapsulates the polar molecules inside the primary solvation shell, drastically reducing the detrimental decomposition of solvents. Finally, the assembled high-voltage cell provides high capacity retention (Li||LiNi0.8Co0.1Mn0.1O2: >90%) during 200 charge/discharge cycles under strict conditions. The capsule-like electrolyte also enables a 420 mAh pouch cell with a cell-level energy density of 440 Wh kg–1 along with long cycling stability over 150 cycles (retention: 92%).

Voltage and Temperature Limits of Advanced Electrolytes for Lithium-Metal Batteries: Isik Su Buyuker, Ben Pei, Hui Zhou, Xia Cao, Zhiao Yu, Sufu Liu, Weiran Zhang, Wu Xu, Ji-Guang Zhang, Zhenan Bao, Yi Cui, Chunsheng Wang, and M. Stanley Whittingham;  ACS Energy Lett. 2023, 8, 4, 1735–1743 (https://doi.org/10.1021/acsenergylett.3c00235)

Abstract

Several advanced electrolytes (mainly ether-based) have shown promising electrochemical performance in high-energy-density lithium-metal batteries. This work evaluates their thermal stability under abuse conditions to elucidate their safety limits compared to carbonate electrolytes typically used in Li-ion batteries. Electrolyte stability was assessed in conjunction with a LiNi0.8Mn0.1Co0.1O2 cathode and a Li-metal anode at ultra-high voltages (≤4.8 V) and temperatures (≤300 °C). The onset and extent of heat release were monitored via isothermal microcalorimetry and differential scanning calorimetry. Most ether-based electrolytes show improved thermal resilience over carbonate electrolytes. While extreme voltages severely destabilize the ether-based electrolytes, a phosphate-based localized high-concentration electrolyte exhibits improved stability over carbonate electrolytes, even at 60 °C. Although thermal analysis during the first charge process may be insufficient to conclude the long-term advantages of these electrolytes, a more stable electrolyte identified under extreme voltage and temperature conditions provides valuable guidance for the safety of future electrolyte designs.

Lithium-Ion Battery Recycling─Overview of Techniques and Trends: Zachary J. Baum, Robert E. Bird, Xiang Yu, and Jia Ma; ACS Energy Lett. 2022, 7, 2, 712–719 (https://doi.org/10.1021/acsenergylett.1c02602)

Abstract: From their initial discovery in the 1970s through the awarding of the Nobel Prize in 2019, the use of lithium-ion batteries (LIBs) has increased exponentially. (1−4) As the world has grown to love and depend on the power and convenience brought by LIBs, their manufacturing and disposal have increasingly become subjects of political and environmental concerns. (5,6) World reserves of lithium, cobalt, and other metals are limited and unevenly distributed, while their mining is energy and labor intensive and creates considerable pollution. (7,8) More than 70% of the world’s cobalt comes from Congo, (9) with no other country producing more than 5%. China and Mozambique produce 70% of the world’s natural graphite, an important material for anodes. (10) As a result, natural disasters, war, or resource allocation decisions may also change the availability of these materials.

Efficient Extraction of Lithium from Anode for Direct Regeneration of Cathode Materials of Spent Li-Ion Batteries: Junxiong Wang, Jun Ma, Kai Jia, Zheng Liang, Guanjun Ji, Yun Zhao, Baohua Li, Guangmin Zhou, and Hui-Ming Cheng;  ACS Energy Lett. 2022, 7, 8, 2816–2824 (https://doi.org/10.1021/acsenergylett.2c01539)

Abstract

The recycling of lithium-ion batteries is important due to limited metallic resources and environmental protection. However, most current studies aim at only extracting valuable components from cathode materials, and the lithium in the anode is usually ignored due to its low concentration. Herein, we develop an integrated recycling strategy for both cathode and anode materials. Batteries are disassembled, and lithium in lithiated graphite is extracted in water and converted to Li2CO3 after absorbing CO2 from the air, which is then used for the direct regeneration of LiCoO2 and LiNi0.5Mn0.3Co0.2O2, while the degraded graphite is regenerated by the delithiation and activation. LiCoO2 with different degrees of failure can retrieve a capacity of 130 mAh/g, while degraded graphite can realize a capacity of 370 mAh/g after regeneration, values which are comparable to commercial materials. Importantly, no external lithium salt is necessary, and water is the only reagent used during regeneration of the cathode material.