富锂锰基正极材料Li2Ni02Mn06O2包覆改研究.docVIP

河 北 工 业 大 学 毕 业 论 文 作 者： 刘浩 学 号： 111978 学 院： 材料科学与工程学院 系(专业)： 功能材料111 题 目： 富锂锰基正极材料Li1.2Mn0.54Ni0.13Co0.13O2 包覆改性研究 指导者： 王丽 副教授 评阅者： 2015 年 6月 12日 毕业设计（论文）中文摘要 富锂锰基正极材料Li1.2Mn0.54Ni0.13Co0.13O2包覆改性研究 摘要： 本文以Mn0.54Ni0.13Co0.13(OH)2为前驱体、Li2CO3为锂源，通过高温固相法合成富锂锰基正极材料Li1.2Mn0.54Ni0.13Co0.13O2。用液相法对其进行AlF3包覆，采用XRD和SEM对材料的结构和形貌进行表征，采用恒流充放电测试对材料的电化学性能进行表征。分别以AlF3包覆量、包覆溶液pH值和热处理温度为考察因素进行单因素实验以确定最优的包覆工艺。结果表明，当包覆量为2wt.%，包覆溶液pH=9，热处理温度为400°C时，材料的首次充放电性能和倍率放电性能最好。首次充放电效率由58.7%提高到73.6%，0.2C、0.5C1.0C下放电比容量分别由184.9mAh/g、171.4mAh/g和153.0mAh/g239.6mAh/g、229.9mAh/g和215.9mAh/g2wt.%，包覆溶液pH=9，热处理温度为450°C时，材料的循环性能最好，在0.5C时50次循环后放电比容量由143.6mAh/g提高到176.7mAh/g。 关键词： 富锂正极材料 Li1.2Mn0.54Ni0.13Co0.13O2 AlF3包覆 电化学性能 毕业设计（论文）外文摘要 Research on the coating modification of Li1.2Mn0.54Ni0.13Co0.13O2 cathode material Abstract Li1.2Mn0.54Ni0.13Co0.13O2 cathode material was synthesized by high-temperature solid-state method using Mn0.54Ni0.13Co0.13(OH)2 as precursor and Li2CO3 as lithium source.AlF3 coating was carried out by liquid phase method.The structure and morphology of the materials were characterized by XRD and SEM, and the electrochemical properties of the materials were characterized by constant-current charge/discharge tests. The AlF3 coating amount, pH value of coating solution and heat treatment temperature were regarded as single factors to determine the optimal parameters of AlF3 coating process.The results show that when coating amount is 2wt%, pH value of coating solution is 9, heat treatment temperature is 400OC, the as-obtained material exhibits the optimal initial charge-discharge performance and rate capability.The initial charge-discharge efficiency increases from 58.7% to 73.6%. The discharge capacities at 0.2C, 0.5C and 1.0C are increased from 153.0mAh/g, 171.4mAh/g and 184