Overcoming the Cathode-Derived Li2CO3 Product by Incorporation of CO2 Capture to Boost Li-CO2 Battery Performance

The development of highly efficient catalysts is critical for the lithium-carbon dioxide (Li-CO2) battery. However, the random deposition of lithium carbonate (Li2CO3) on cathodic active sites leads to catalyst poisoning and severely restricts the discharge capacity. Here, we introduce tetraethylenepentamine (TEPA), an amine-rich redox mediator integrated into the electrolyte, to mediate the CO2 reduction and evolution reactions (CO2RR/CO2ER) through a coupled cation-electron transfer mechanism. The multiple amine groups in TEPA regulate the adsorption and decomposition of reaction intermediates, thereby suppressing catalyst deactivation, mitigating voltage polarization, and enabling high discharge capacities up to ∼3984 mAh g-1. Notably, a reversible capacity of 1991 mAh g-1 is maintained even at -20 °C, and the Li-CO2 battery using TEPA demonstrates stable cycling over 100 cycles. This work provides a robust strategy to overcome cathode passivation and unlocks the potential of redox-mediating molecules to promote reversible electrochemistry in metal air batteries.