正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2的合成及电化学性能

Synthesis and electrochemical performance of micro-size LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 cathode material

将液相共沉淀法制备的Ni0.8Co0.1Mn0.1(OH)2与LiOH.H2O混合,固相烧结合成微米级的LiNi0.8Co0.1Mn0.1O2正极材料。XRD谱表明,合成的LiNi0.8Co0.1Mn0.1O2正极材料为典型的α-NaFeO2层状结构,无杂质峰;从SEM像可以看出,产物颗粒为类球形,分散性好,由一次粒子紧密堆积而成,平均粒径为3μm;电化学测试结果表明,在2.8～4.3 V电压范围内,750℃焙烧15 h合成的LiNi0.8Co0.1Mn0.1O2材料的电化学性能最优,0.1 C时,其首次放电容量为186.748 mA.h/g,分别高于700和800℃时的首次放电容量172.947和180.235 mA.h/g。材料在0.5和2 C时循环40次后,容量保持率分别为98.32%和88.72%,循环性能良好。

The micro-size LiNi0.8Co0.1Mn0.1O2 cathode material was synthesized by mixing Ni0.8Co0.1Mn0.1（OH）2 and LiOH-H2O via solid state reaction followed by heating to elevated temperatures.X-ray diffraction（XRD） patterns show that all samples exhibit typical α-NaFeO2 structure without any other impurities.The scanning electron microscopy（SEM） reveals that the primary particles agglomerate to form secondary particles with an average size of 3 μm,and the particles are near-spherical and well distributed.In the voltage range of 2.8-4.3 V,LiNi0.8Co0.1Mn0.1O2 synthesized at 750 ℃ for 15 h exhibits a higher initial discharge capacity of 186.748 mA-h/g at 0.1 C compared with those of LiNi0.8Co0.1Mn0.1O2 synthesized at 700 and 800 ℃（172.947 and 180.235 mA-h/g,respectively）.The material has excellent cycling performance,in which the capacity retention at the rates of 0.5 and 2 C are 98.32% and 88.72%,respectively,after 40 cycles.