• Energy Research
• 13. Climate action close

Electrochemical CO2 reduction (CO2RR) using renewable energy sources represents a sustainable means of producing carbon-neutral fuels. Unfortunately, low energy efficiency, poor product selectivity, and rapid deactivation are among the most intractable challenges of CO2RR electrocatalysts. Here, we strategically propose a "two ships in a bottle" design for ternary Zn-Ag-O catalysts, where ZnO and Ag phases are twinned to constitute an individual ultrafine nanoparticle impregnated inside nanopores of an ultrahigh-surface-area carbon matrix. Bimetallic electron configurations are modulated by constructing a Zn-Ag-O interface, where the electron density reconfiguration arising from electron delocalization enhances the stabilization of the *COOH intermediate favorable for CO production, while promoting CO selectivity and suppressing HCOOH generation by altering the rate-limiting step toward a high thermodynamic barrier for forming HCOO*. Moreover, the pore-constriction mechanism restricts the bimetallic particles to nanosized dimensions with abundant Zn-Ag-O heterointerfaces and exposed active sites, meanwhile prohibiting detachment and agglomeration of nanoparticles during CO2RR for enhanced stability. The designed catalysts realize 60.9% energy efficiency and 94.1 ± 4.0% Faradaic efficiency toward CO, together with a remarkable stability over 6 days. Beyond providing a high-performance CO2RR electrocatalyst, this work presents a promising catalyst-design strategy for efficient energy conversion.

AbstractWorldwide 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.