高取向富锂正极材料的合成及电化学性能研究

Synthesis and Electrochemical Performance of Highly Oriented Li-rich Cathode Material

摘要:

以六亚甲基四胺（HMT）为导向剂，通过水热法，在不同温度下合成了六边形薄片状的高取向三元前驱体NixCoyMn1-x-y(OH)2，采用氯化钾与氯化钠的混合熔盐法对前驱体进行煅烧后得到高取向富锂正极材料。经X射线衍射、扫描电镜等表征，材料具有良好的层状结构，在(003)晶面具有很高的择优取向。电化学测试结果表明，在0.1C倍率下(20mA/g)，材料的首次放电容量为282.5mAh/g；1C倍率下经30次循环放电容量从195.7 mAh/g降至178.8 mAh/g，容量保持率为91.4%；当倍率分别为2 C和5 C时，材料的放电容量分别为150.6 mAh/g和110.0 mAh/g。材料具有良好的循环稳定性和倍率性能。

Abstract:

The high-oriented ternary precursors NixCoyMn1-x-y(OH)2 with a hexagonal morphology have been obtained via a hydrothermal method by using hexamethylenetetramine (HMT) as directing agent at different temperature. A NaCl/KCl molten salt method was used to calcine the highly oriented Li-rich cathode material. The results of XRD and SEM show that the obtained Li-rich material has a highly (003) orientation and good layer structure. The initial discharge capacity of the material is 282.5 mAh/g at rate 0.1C; When the rate changes to 1C, the discharge capacity decline to 178.8 mAh/g from 195.7 mAh/g after 30 cycles. When the rate changes to 2 C and 5 C, the discharge capacity respectively is 150.6 mAh/g and 110.0 mAh/g. The materials have good cycle stability and rate performance.