锂离子电池正极材料LiNi_(0.4)Co_(0.2)Mn_(0.4)O_2的制备与性能研究

以自制Ni0.4Co0.2Mn0.4(OH)2前驱体和Li_2CO_3为原料,在空气气氛下采用固相烧结工艺制备了LiNi_(0.4)Co_(0.2)Mn_(0.4)O_2锂离子电池正极材料。通过SEM和XRD等手段对材料烧结前后形貌与结构进行表征,并测试了烧结后锂离子电池正极材料的电化学性能。结果表明,Ni0.4Co0.2Mn0.4(OH)2前驱体具有良好的片状嵌入结构,且烧结制备的LiNi_(0.4)Co_(0.2)Mn_(0.4)O_2正极材料混排因子c/a=4.967 3,阳离子混排因子I(003)/I(104)=1.25、I(006+102)/I(101)=0.333、I(018)/I(110)=0.87,表明LiNi_(0.4)Co_(0.2)Mn_(0.4)O_2具有良好的层状结构。在2.5~4.6V、0.2C和0.5C下,LiNi_(0.4)Co_(0.2)Mn_(0.4)O_2正极材料的首次放电比容量分别为166和154mAh/g,循环80次后容量分别保持为111和100mAh/g,具有良好的电化学性能。

Synthesis and Performance Study of LiNi0.4Co0.2Mn0.4O2 Cathode Material for Lithium-ion Batteries

LiNi0.4Co0.2Mn0.4O2 cathode material for Li-ion batteries was synthesized by sintering process with Ni0.4Co0.2Mn0.4(OH)2 precursor and Li2CO3 as raw materials in air atmosphere. Morphology and crystal structure were evaluated by SEM and XRD before and after sintering Ni0.4Co0.2Mn0.4(OH)2 precursor with Li2CO3. Electrochemical properties of LiNi0.4Co0.2Mn0.4O2 cathode material were tested. The results show that primary particles of Ni0.4Co0.2Mn0.4(OH)2 precursor are of obvious layered structure. Cathode material LiNi0.4Co0.2Mn0.4O2 has obvious hexagonal layered type structure with low cation mixing factor of c/a=4.967 3, ratio of characteristic peaks I(003)/I(104)=1.25, I(006+102)/I(101)=0.333, and I(018)/I(110)=0.87. The initial discharge capacity of LiNi0.4Co0.2Mn0.4O2 is 166 and 154 mAh/g respectively in the voltage range of 2.5~4.6 V at 0.2C and 0.5C. The reversible capacity is 111 and 100 mAh/g respectively after 80 cycles.