Activated Co in Thiospinel Boosting Li₂CO₃ Decomposition in Li-CO₂ Batteries

Catalytic reactions mainly depend on the adsorption properties of reactants on the catalyst, which provides a perspective for the design of reversible lithium-carbon dioxide (Li-CO₂) batteries including CO₂ reduction (CO₂RR) and CO₂ evolution (CO₂ER) reactions. However, due to the complex reaction process, the relationship between the adsorption configuration and CO₂RR/CO₂ER catalytic activity is still unclear in Li─CO₂ batteries. Herein, taking Co₃S₄ as a model system, nickel (Ni substitution in the tetrahedral site to activate cobalt (Co) atom for forming multiatom catalytic domains in NiCo₂S₄ is utilized. Benefiting from the special geometric and electronic structures, NiCo₂S₄ exhibits an optimized adsorption configuration of lithium carbonate (Li₂CO₃), promoting its effective activation and decomposition. As a result, the Li-CO₂ batteries with NiCo₂S₄ cathode exhibit remarkable electrochemical performance in terms of low potential gap of 0.42 V and high energy efficiency of 88.7%. This work provides a unique perspective for the development of highly efficient catalysts in Li-CO₂ batteries.