Cathode architecture and active site engineering in lithium-CO2 batteries

Secondary lithium-carbon dioxide (Li-CO2) batteries possess great application potential for CO2 fixation and electrochemical energy storage. Nevertheless, the formation of stable and insulating discharge intermediates and the complexity of multiphase interfacial reactions lead to large potential polarization and inferior redox reversibility. In this review, we systematically discuss the charge/discharge mechanisms of Li-CO2 redox reaction. Latest research achievements about cathode architecture and active site engineering are summarized in detail. In particular, representative engineering strategies (i.e., morphological modulation, dimensional hybridization, defect, single atoms, heterostructure, and synergy engineering) of cathode materials for high-performance Li-CO2 batteries are systematically introduced. Lastly, the current research progress is briefly summarized and the future challenge and potential opportunities for further development of advanced Li-CO2 batteries are proposed.