【摘要】 尖晶石锰酸锂（LiMn₂O₄）是低成本锂离子电池的理想正极材料。采用动态水热法成功地一步合成了一系列粒径较小（<50nm）且分布较窄的LiMn₂O₄材料,并运用XRD,SEM,CV,EIS和充放电测试等多种方法表征其晶相、形貌和电化学性能。研究结果表明水热温度对产物成分和电化学性能有很大影响。在180℃和200℃条件下制得的LiMn₂O₄材料为纯相尖晶石晶型。180℃合成的材料具有更好的电化学性能,在1C倍率循环时,LiMn₂O₄材料的首次放电比容量为102.4mAh/g,循环50周后容量保持率为95.5%。600℃热处理对材料结构和性能具有明显的改善作用,1C倍率循环时,首次放电比容量达到112.7mAh/g,循环50周后容量保持率为94.2%。研究成果为低成本锰酸锂正极材料的制备提供了一条理想的工艺路线。更多还原

【Abstract】 Spinel LiMn₂ O₄ is considered as promising cathode material for low-cost lithium ion battery due to its high power density,low cost and good safety.In this work,a series of LiMn₂ O₄ materials with small sizes（<50 nm）and narrow size distributions were successfully synthesized via one-step dynamic hydrothermal route.Various measurements including XRD,SEM,CV,EIS and charging/discharging tests were conducted to investigate the crystalline phase,morphology and electrochemical performances of as-prepared materials. The results demonstrated that the temperature of the hydrothermal process had significant influences on the components and electrochemical behaviors of the products.The LiMn₂ O₄ products synthesized at 180 ℃ and 200 ℃ both possessed pure spinel crystal phase,yet the sample prepared at 180℃exhibited better electrochemical performance than that prepared at 200℃,which showed initial reversible capacity of 102.4 mAh/g and capacity retention of 95.5%after 50 cycles at 1 C.In addition,heat-treatment at 600 ℃ could greatly improve the structure and performance of the LiMn₂ O₄ material with the initial reversible capacity and the capacity retention being112.7 mAh/g and 94.2%after 50 cycles at 1 C,respectively.The presented work here has offered an ideal route for preparations of low-cost LiMn₂ O₄ cathode materials.更多还原