Overall Carbon‐neutral Electrochemical Reduction of CO₂ in Molten Salts using a Liquid Metal Sn Cathode

Abstract

An overall carbon‐neutral CO2 electroreduction requires enhanced conversion efficiency and intensified functionality of CO2‐derived products to balance the carbon footprint from CO2 electroreduction against fixed CO2. A liquid Sn cathode is herein introduced into electrochemical reduction of CO2 in molten salts to fabricate core–shell Sn−C spheres (Sn@C). An in situ generated Li2SnO3/C directs a self‐template formation of Sn@C. Benefitting from the accelerated reaction kinetics from the liquid Sn cathode and the core–shell structure of Sn@C, a CO2‐fixation current efficiency higher than 84 % and a high reversible lithium‐storage capacity of Sn@C are achieved. The versatility of this strategy is demonstrated by other low melting point metals, such as Zn and Bi. This process integrates energy‐efficient CO2 conversion and template‐free fabrication of value‐added metal‐carbon, achieving an overall carbon‐neutral electrochemical reduction of CO2.