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. By Ni substitution in the tetrahedral sites of Co‐based thiospinel, Co atoms are activated to construct catalytic domain with multiple active sites. Resultant adsorption configuration leads to enhanced interaction between Li2CO3 and NiCo2S4, which result in reduced energy barrier for Li2CO3 decomposition and excellent catalytic activity to CO2 evolution reaction. As a result, the charge voltage is significantly reduced.