Electronic State Modulation and Reaction Pathway Regulation on Necklace‐Like MnOx‐CeO2@Polypyrrole Hierarchical Cathode for Advanced and Flexible Li–CO2 Batteries

Abstract Li–CO 2 batteries provide the possibility for synchronous implementation of carbon neutrality and development of advanced energy storage devices. Catalytic cathodes composed of well‐designed conductive substrates and active materials are critical to the improvement of Li–CO 2 batteries. Herein, MnO x ‐CeO 2 hollow nanospheres are strung together by conductive polypyrrole (PPy) via post‐in‐situ polymerization, and a necklace‐like MnO x ‐CeO 2 @PPy hierarchical cathode with excellent flexibility and self‐supporting feature is constructed. Benefitting from the excellent conductivity of PPy, the binder‐free structure, and the greatly exposed catalytic active sites, the MnO x ‐CeO 2 @PPy based Li–CO 2 batteries exhibit superior discharge capacity (13631 mA h g –1 at 100 mA g –1 ) and cycle performance (253 cycles) as well as a low overpotential of 1.49 V. Of particular note, the flexible freestanding film is confirmed as a potential catalytic cathode for flexible Li–CO 2 batteries. The density functional theory calculations, combined with experimental tests, are performed to gain insights into the enhanced substrate adsorption capacity, the optimized electronic structure of the active surface MnO x ‐CeO 2 (111), the concentrated electrons on the reaction sites Ce, and the electrochemical mechanism. This work initiates the use of conductive polymers for catalytic cathodes in Li–CO 2 batteries, which provide new opportunities for promoting the performance of various energy storage devices.