Oxygen vacancy engineering of vertically aligned NiO nanosheets for effective CO2 reduction and capture in Li-CO2 battery

Abstract The Li-CO2 battery with the concept of turning waste into treasure has aroused great scientific research enthusiasm recently, but unfortunately it is a long shot for the large-scale applications of Li-CO2 battery due to its huge overpotential and poor cycling life at current stage. Herein, NiO nanosheets engineered by oxygen vacancy growing vertically on carbon clothes (NiO-Vo@CC) was developed as viable catalyst for both CO2 reduction reaction (CO2RR) and CO2 evolution reaction (CO2ER) in Li- CO2 system. The oxygen vacancy decorated by surplus electron will not only work as electron donor (Lewis base) surface to activated the electron-deficient carbon atom in CO2 but also narrow the band gap of NiO, therefore optimized CO2 conversion kinetic can be obtained by using defective NiO-Vo@CC electrode. The utilization of defect engineering to achieve performance improvement in aprotic Li-CO2 battery is still in its infancy at current stage and thus our research initially corroborates that modulation of the surface property via defect engineering can serve as valid strategy to design high performance electrodes for Li-CO2 battery.