LiNi_(1/3)Mn_(1/3)Co_(1/3)O_2-zFz正极材料的合成及电化学性能

Synthesis and electrochemical performance of LiNi_(1/3)Mn_(1/3)Co_(1/3)O_2-zFz cathode materials for lithium ion batteries

以共沉淀碳酸盐为前驱体制备了层状LiNi1/3Mn1/3Co1/3O2正极材料,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、充放电测试、差分计时电位等方法研究了其结构与电化学性能,同时研究了F-掺杂对于材料电化学性能和结构的影响。SEM分析表明,LiNi1/3Mn1/3Co1/3O2产物基本为球形颗粒。F-掺杂后,粉末形状变得不规则。LiNi1/3Mn1/3Co1/3O2材料在2.5～4.4V电位区间内,首次放电比容量为162mAh·g-1,50次循环后容量保持率为93.2%。适量的F-掺杂能显著提高材料的循环性能,F-掺杂量z为0.1时,50次循环后容量保持率为98.1%。

LiNi1/3Mn1/3Co1/3O2 cathode materials were synthesized by using the co-precipitated metal carbonate as precursor. Structural and electrochemical properties were characterized by XRD, SEM, differential chronopotentiometry and galvanostatic cycling, and effect of F-doping on structural and electrochemical properties of LiNi1/3Mn1/3Co1/3O2 was also investigated. SEM results showed that LiNi1/3Mn1/3Co1/3O2powders are spherical particles. Fluorine doped materials composed of irregular particles. In the voltage range of 2.5-4.4 V, the LiNi1/3Mn1/3Co1/3O2cathode material has an initial discharge specific capacity of 162 mAh·g^-1, and capacity retention rate is 93.2% up to 50 cycles. Appropriate F doping can dramatically enhance the cycle performance of LiNi1/3Mn1/3Co1/3O2 cathode materials. After 50 charge-discharge cycles, the samples with z = 0.1 F^- doing has 98.1% capacity retention rate.