A novel research on the positive effects of oxygen vacancies for interstitial N-doped MnO2 on lithium-ion diffusion

Abstract In defect engineering, doping and vacancy are effective ways to improve the electrochemical performance of electrode material. For the first time, we introduce N dopants and tunable oxygen vacancies into electrolytic MnO2 with graphite as skeleton by a simple wet ball milling. The nanocomposites (NEG) exhibit excellent rate performance under various current densities. The density functional theory (DFT) calculations and climbing image-nudged elastic band (CI-NEB) demonstrate the interstitial N dopants can improve electronic conductivity and lithium-ion diffusion. This research will facilitate the deep understanding of the mechanism of lithium-ion diffusion and provide a novel idea for the study on the defect engineering.