中文摘要：

锂空气电池的理论能量密度约是锂离子电池的10倍,因而受到研究者的广泛关注。碳质材料由于其稳定的结构和良好的导电性,目前仍作为锂空气电池的主要正极材料。通过KOH活化调节碳纳米管的表面特性和微观结构,将其作为锂空气电池正极材料,研究碳纳米管的微观结构变化对放电产物及电化学行为的影响。结果表明,当碳纳米管管壁被剥开导致大量边界原子外露,形成碳纳米管-石墨烯杂化结构,极大提高了碳纳米管正极的反应活性,放电容量和循环性能显著增加,放电产物分布均匀及颗粒减小,充电平台也显著降低。

英文摘要：

The Li-air battery has attracted considerable attention owing to its high energy density,which is approximately 10 timeslarger than that of a conventional Li-ion battery. Carbon is frequently used as the cathode material because of its stable structure and excellent conductivity. The surface properties and microstructure of carbon nanotubes （CNTs） were modified by KOH activation and its effects on the electrochemical behaviorof CNTs as a cathode material for Li-air batterieswere investigated. Results indicate that the graphitic layer of the CNT outer surface is etched and more edge carbon atoms are exposed after the modification, which generates a CNT-graphene hybrid nanostructure. This hybrid structure provides a large number of active sites that are beneficial for the genera- tion/decomposition of discharge products,leading to a decrease of the charging overpotential and an improvement in cycling stabili-ty.