【摘要】 通过以乙酸镧、乙酸锶和乙酸锰制备的锰酸锶镧(La_0.65Sr_0.35MnO₃)和尖晶石型锰酸锂（LiMn₂O₄）正极材料作为原料,采用溶胶-凝胶法制备了质量分数分别为0.5%、1.0%和2.0%的锰酸锶镧表面包覆的LiMn₂O₄正极材料。采用X-射线衍射（XRD）、扫描电镜（SEM）、充放电循环测试等对包覆材料的结构、形貌和电化学性能进行表征,研究不同包覆比例对材料的微观结构、形貌及在502030型电池中电的化学性能。通过XRD和SEM分析可知,包覆锰酸锶镧对锰酸锂的结构并没有改变,当包覆比例为1.0%时,包覆材料分布均匀。对材料进行电化学性能测试发现,纯相LiMn₂O₄首次放电比容量为94.5mAh/g,循环500周后容量保持率为57.78%;包覆比例为1.0%的LiMn₂O₄首次放电比容量为106.2mAh/g,循环500周后容量保持率为64.22%,首次放电比容量增加了12.4%,容量保持率提高了6.44%。结果表明,经过包覆后材料的电化学性能得到了明显提高。更多还原

【Abstract】 Based lanthanum acetate,strontium acetate and acetic acid,prepared strontium and manganese acetate manganese strontium lanthanum and spinel lithium manganese acid（LiMn₂O₄）anode materials as the raw materials,lanthanum strontium manganate surface coated LiMn₂O₄ anode materials were synthesized through the sol-gel method,which coating quality were 0,0.5%,1.0% and 0.5%,respectively.Using X-ray diffraction（XRD）,scanning electron microscopy（SEM）and charge-discharge cycle test,the composition,structure,morphology and electrochemical properties of the target material were characterized.The effects of different coating ratios on the structure,morphology and electrochemical properties of the composites were investigated.By XRD and SEM analysis,it can be seen that the structure of the coated lithium manganate had not changed,and when the coating ratio was 1%,the coating material was evenly distributed.The initial discharge capacity of pure LiMn₂O₄ was 94.5 mAh/g,and the capacity retention rate was 57.78% after 500 cycles.The first discharge capacity of LiMn₂O₄ with a coating ratio of 1% was 106.2 mAh/g.After 500 cycles,the retention rate was 64.22%,the initial discharge capacity increased by 12.4%,and the capacity retention rate increased by 6.44%.The results showed that the material electrochemical properties were obviously improved after the coating.更多还原