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

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 leading to both the activity and selectivity enhancement of the CO2 electroreduction to formate. The s-SnLi electrocatalyst exhibited one of the best CO2-to-formate performances, including 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 an efficient approach to incorporate the electron localization and lattice strain as the active catalytic sites to synergistically achieve highly efficient CO2-to-formate electrosynthesis toward potential commercialization.