Electron Localization and Lattice Strain Induced by Surface Lithium Doping Enable Ampere-Level Electrosynthesis of Formate from CO2

Abstract

The electrochemical CO₂ conversion to formate is a promising approach for reducing CO₂ level and obtaining value-added chemicals, but its partial current density is still insufficient to meet the industrial demands. Herein, we developed a surface-lithium-doped tin (s-SnLi) catalyst by controlled electrochemical lithiation. Density functional theory calculations indicated that the Li dopants introduced electron localization and lattice strains on the Sn surface, thus enhancing both activity and selectivity of the CO₂ electroreduction to formate. The s-SnLi electrocatalyst exhibited one of the best CO₂ -to-formate performances, with a partial current density of -1.0 A cm^-2 for producing formate and a corresponding Faradaic efficiency of 92 %. Furthermore, Zn-CO₂ batteries equipped with the s-SnLi catalyst displayed one of the highest power densities of 1.24 mW cm^-2 and an outstanding stability of >800 cycles. Our work suggests a promising approach to incorporate electron localization and lattice strain for the catalytic sites to achieve efficient CO₂ -to-formate electrosynthesis toward potential commercialization.

Keywords: CO2 electroreduction; Zn-CO2 battery; electron localization; formate; lattice strain.