Surface oxygen vacancies boosted high rate performance of porous MnO2 anode for lithium-ion batteries

The main obstacles to the development of manganese-based oxide anode materials for lithium-ion batteries (LIBs) are inherently low conductivity and sluggish electrochemical kinetics. In this work, we propose a strategy of introducing oxygen vacancies (Vo) on the surface of nanostructure at room temperature and atmospheric pressure to improve the electrochemical performance of anode materials. Porous MnO2 spheroids with 11.2% Vo are fabricated by a ball milling method using commercial electrolytic MnO2. The as-synthesized MnO2 is composed of 20–30 nm nanoparticles. The optimized MnO2 shows an excellent rate capability of 350 mAh g−1 at 6.4 A g−1 and high specific capacity of 1200 mAh g−1 after 650 cycles under 2 A g−1. The boosted electrochemical performance is attributed to the porous hierarchical structure and the appropriate Vo concentration involved in the MnO2. In addition, the enhanced Li+ diffusion coefficient is demonstrated through the kinetics analysis. The approach provides a facile route via tunable Vo concentration for improving the electrochemical performance of manganese-based oxide anode materials for LIBs. • The porous MnO2 spheroids with tunable Vo concentrate were synthesized by a ball milling method. • The MnO2 spheroids are composed of 20-30 nm nanoparticles. • The MnO2 spheroids exhibit an excellent rate performance and cycling stability. • The ball mill is facile, environmentally friendly, economical for the mass industrial scale.