Abstract
Recent advancements in metal-CO(2) batteries with enhanced energy efficiency in a sustainable manner largely rely on catalytic improvements to accelerate the sluggish kinetics of the CO(2) reduction and evolution reactions (CO(2)RR/CO(2)ER) occurring at the multiphase interface. However, conventional solid and liquid catalysts often increase the adsorption of both reactant gas and solid-phase discharge products, lowering discharge overpotentials but impeding product decomposition during charging. This trade-off complicates efforts to simultaneously reduce charge-discharge overpotentials and improve overall battery efficiency. Here, we introduce an ethanol vapor-driven strategy for Mg-CO(2) batteries-distinct from traditional solid and liquid catalysis-that selectively enhances CO(2) adsorption while limiting the adsorption of discharge products. This approach enables high energy efficiency through the formation and decomposition of the first conductive organic multicarbon (C(2+)) product in metal-CO(2) batteries, specifically Mg(CH(3)COO)(2)·4H(2)O. The Mg-CO(2) battery delivers outstanding discharge and charge capacities beyond 50 000 mAh g(-1), coupled with stable cycling over 600 h, ranking it the best Mg-CO(2) system reported to date. This catalyst-free strategy for multicarbon production holds potential for applications in CO(2) reduction and carbon fixation.