Constructing lithium-ion fast pathways via ZnO surface modification to enhance rate capability of graphite anode materials

Abstract

Graphite materials have attracted widespread attention and application as anodes in lithium-ion batteries due to their abundant raw materials and environmental friendliness. However, poor rate performance is one of the most challenging issues for graphite anodes. In this work, a novel zinc oxide-graphite composite material has been fabricated, which effectively reduces the diffusion resistance of lithium ions during the charge-discharge process. Based on the analysis of the DFT calculations, the introduction of zinc oxide would be an effective way to improve the rate properties of graphite anode materials, owing to the higher lithium-ion diffusion kinetics. The concentration of zinc oxide has been optimized for the electrochemical performances of the composite electrode. Particularly, the 1%ZnO-graphite composite electrode demonstrates significant electrochemical performance with a discharge specific capacity of 337.6 mAh g−1 after 300 cycles at 1C (pure graphite is 300.6 mAh g−1) and excellent rate performance with 190 mAh g−1 at 5C (pure graphite is only 66 mAh g−1). These results pave a new direction for preparing the high rate and long cycle graphite anode materials.