Li-CO2 Electrochemistry: A New Strategy for CO2 Fixation and Energy Storage

Large energy is required for traditional CO2 fixation, leading to more CO2 emission and additional pollutants. Recently, integrating renewable energy with CO2 fixation has attracted increasing attention as a sustainable strategy. Here, based on a systematic investigation on aprotic Li-CO2 electrochemistry, we first provide an alternative strategy for either CO2 fixation or energy storage. Both strategies share the same CO2 reduction process with the formation of Li2CO3 and carbon. Subsequently, CO2 fixation is achieved through a rechargeable/irreversible oxidation process, during which Li2CO3 is decomposed, while the carbon obtained remains fixed. Moreover, a reversible Li-CO2 battery system has been realized based on co-oxidization of the resulting carbon and Li2CO3 using a Ru catalyst. Consequently, by shedding light on the fundamental reaction mechanism of aprotic Li-CO2 electrochemistry, the proof of concept presented here provides strong theoretical underpinning for developing flexible routes for both CO2 fixation and Li-CO2 energy storage.