Worldwide trends in mobile electrification, largely driven by the popularity of electric vehicles (EVs) will skyrocket demands for lithium‐ion battery (LIB) production. As such, up to four million metric tons of LIB waste from EV battery packs could be generated from 2015 to 2040. LIB recycling directly addresses concerns over long‐term economic strains due to the uneven geographic distribution of resources (especially for Co and Li) and environmental issues associated with both landfilling and raw material extraction. However, LIB recycling infrastructure has not been widely adopted, and current facilities are mostly focused on Co recovery for economic gains. This incentive will decline due to shifting market trends from LiCoO2 toward cobalt‐deficient and mixed‐metal cathodes (eg, LiNi1/3Mn1/3Co1/3O2). Thus, this review covers recycling strategies to recover metals in mixed‐metal LIB cathodes and comingled scrap comprising different chemistries. As such, hydrometallurgical processes can meet this criterion, while also requiring a low environmental footprint and energy consumption compared to pyrometallurgy. Following pretreatment to separate the cathode from other battery components, the active material is dissolved entirely by reductive acid leaching. A complex leachate is generated, comprising cathode metals (Li+, Ni2+, Mn2+, and Co2+) and impurities (Fe3+, Al3+, and Cu2+) from the current collectors and battery casing, which can be separated and purified using a series of selective precipitation and/or solvent extraction steps. Alternatively, the cathode can be resynthesized directly from the leachate.

Capacitive deionization (CDI) is an emerging desalination technology for effective removal of ionic species from aqueous solutions. Compared to conventional CDI, which is based on carbon electrodes and struggles with high salinity streams due to a limited salt removal capacity by ion electrosorption and excessive co-ion expulsion, the emerging Faradaic electrodes provide unique opportunities to upgrade the CDI performance, i.e., achieving much higher salt removal capacities and energy-efficient desalination for high salinity streams, due to the Faradaic reaction for ion capture. This article presents a comprehensive overview on the current developments of Faradaic electrode materials for CDI. Here, the fundamentals of Faradaic electrode-based CDI are first introduced in detail, including novel CDI cell architectures, key CDI performance metrics, ion capture mechanisms, and the design principles of Faradaic electrode materials. Three main categories of Faradaic electrode materials are summarized and discussed regarding their crystal structure, physicochemical characteristics, and desalination performance. In particular, the ion capture mechanisms in Faradaic electrode materials are highlighted to obtain a better understanding of the CDI process. Moreover, novel tailored applications, including selective ion removal and contaminant removal, are specifically introduced. Finally, the remaining challenges and research directions are also outlined to provide guidelines for future research.

Rechargeable zinc‐ion batteries (ZIBs) have emerged as a contender in the area of electrochemical energy storage applications due to their low cost and inherent safety. To optimize the battery performances, ZIBs cathode materials with high capacity and cyclability have been intensively studied, with most attention focused on traditional manganese‐ and vanadium‐based materials. Recently, other novel cathode materials including Prussian blue analogues (PBAs), polyanions, metal sulfides, and organic compounds have begun to gain recognition as promising alternatives. These materials exhibit distinct strength such as high operating voltage, additional capacity by new redox chemistry activation, and/or highly reversible cycling process that are particularly desirable for ZIBs applications. To provide the highlight they deserve, this review focuses on introducing the recent progresses of these ZIBs cathodes and demonstrating common strategies adopted for material modification and optimization. Finally, systematic comparisons among the cathode materials are analyzed, along with challenges and perspectives on each category of the cathodes.

The recycling of lithium‐ion batteries addresses concerns over waste accumulation and the depletion of critical mineral resources associated with their large‐scale production and application. In article number https://doi.org/10.1002/cey2.29, Tyler Or, Storm Gourley, Karthikeyan Kaliyappan, Aiping Yu, and Zhongwei Chen review new recycling methods for cathodes comprising a mixed‐metal composition in the context of meeting demands for the growing electric vehicle market.

excellent safety and low cost. However, electrochemical corrosion, hydrogen evolution, and dendrite growth from the Zn anode result in poor cycle performance of the Zn-ion battery, which is much more severe at high current density, active material loading, and depth of discharge (DOD). [2] In addition, the electrochemical performance of Zn-ion batteries severely deteriorates under low temperature due to the sluggish reaction kinetics. Therefore, it is vital to develop rational strategies to improve the reversibility of the Zn anode, especially under the above-mentioned harsh conditions. [3][4][5] Recent studies have shown that regulating the solvation structure of aqueous electrolytes can alter the behavior of Zn deposition and dendrite growth. [6] Cur-Editor's Choice