高性能单晶LiNi0.5Co0.2Mn0.3O2材料的制备工艺及性能研究

Study on preparation and properties of high performance single crystal LiNi0.5Co0.2Mn0.3O2 material

通过共沉淀法并辅助球磨工艺制备了Ni(0.5)Co(0.2)Mn(0.3)(OH)2前驱体,采用掺杂和固相烧结工艺制备了单晶LiNi(0.5)-Co(0.2)Mn(0.3)O2材料,并对其进行扫描电子显微镜法(SEM)、一次粒子尺寸测量、充放电容量、倍率性能、循环性能等性能指标测试,结果表明:烧结温度和铝掺杂量能够显著影响Li Ni(0.5)Co(0.2)Mn(0.3)O2材料烧结过程中一次粒子的成长,一次粒子尺寸的长大明显降低了LiNi(0.5)Co(0.2)Mn(0.3)O2材料的放电容量、首次效率;铝掺杂量为0.2%(质量分数),940℃烧结时,Li Ni0.5Co0.2Mn0.3O2材料一次粒子平均尺寸在3.21μm;3~4.3 V,0.2 C充放电,扣式电池放电比容量为157.8 m Ah/g,首次效率为86.6%;3~4.4 V下充放电,0.5 C/0.1 C、2 C/0.1 C的容量保持率分别为94.7%和86.1%,300次充放电后,容量保持率为91.3%,倍率性能和循环寿命均显著优于市售产品。

Ni0.5Co0.2Mn0.3(OH)2 precursor was prepared by coprecipitation assisted with ball milling. Single crystal Li Ni0.5 Co0.2 Mn0.3 O2 material was prepared by doping and solid phase sintering. SEM, primary grain size, chargedischarge capacity, rate capability and cycle performance were measured. The results show that the sintering temperature and aluminum doping amount can significantly affect grain growth in LiNi0.5Co0.2Mn0.3O2 material sintering process. The growth of primary particle size significantly leads to the decrease of the discharge capacity, initial efficiency and medium voltage of LiNi0.5Co0.2Mn0.3O2. The average grain size is 3.21 μm when Li Ni0.5 Co0.2 Mn0.3 O2 material is sintered at 940 ℃ and aluminum doping amount is 0.2%. During charge-discharge cycle of 3-4.3 V at 0.2 C,the discharge specific capacity and initial efficiency of button battery were 157.8 m Ah/g and 86.6% respectively. The capacity retention of 0.5 C/0.1 C and 2 C/0.1 C are 94.7% and 86.1%, respectively during charging and discharging at 3-4.4 V. After 300 cycles, the capacity retention is 91.3%. The rate capability and cycle life are significantly better than those of marketed products.