锂离子正极材料LiNi0.5Mn0.3Co0.2O2的合成与掺杂Al的性能研究

采用共沉淀法合成镍钴锰氢氧化物前躯体，使其和碳酸锂混合均匀后，高温焙烧合成锂离子正极材料LiNi_0.5Mn_0.3Co_0.2O₂，研究了掺杂Al（OH）₃对材料循环性能的影响.用X射线衍射和扫描电镜对合成的粉末进行了表征，用电性能测试仪研究了材料的电化学性能.研究发现:温度为850 ℃时焙烧的材料具有最优的电性能，1C电流初始放电比容量达到157.2 mAh/g（2.75~4.2V），循环50次放电比容量保持率为94.8 %，循环100次材料的放电比容量保持率为90.1 %.通过少量掺杂Al（OH）₃的电池材料结晶性有所提高，晶型趋于完整，但是材料的放电比容量有所降低，前100次循环掺杂对材料循环稳定性无显著改善效果. 

Synthesis and Al-doping properties of lithium-ion cathode materials LiNi0.5Mn0.3Co0.2O2

The cathode materials LiNi_0.5Mn_0.3Co_0.2O₂ were synthesized through high -temperature calcination mixed with the compound of lithium carbonate and cobalt nickel manganese hydroxide precursor, which prepared by liquid co-precipitation technique. The effect of Al(OH)₃ doped material on cycling performance was studied. The prepared powders were characterized by powder X-ray diffraction, scanning electron microscope, and electro-chemical character of the material was studied by electric performance testing instrument. It was proved that the material calcinated at 850 ℃ showed the best performance, the first discharge capacity of 2.75~4.2 V and at 1 C was 157.2 mAh/g, the capacity retention ratio was 94.8 % after 50 cycles and 90.1 % after 100 cycles. Through a small amount of Al doping, the crystalline of the material was improved and the crystal type tended to be complete while the discharge capacity decreased. There is no obvious influence on the material's cycle stability at the former 100 cycles.