氢氧化物共沉淀法制备LiMn0.45Ni0.45Co0.1O2正极材料的反应条件

通过氢氧化物共沉淀法制备了Mn0.45Ni0.45Co0.1(OH)2, 研究了反应条件对产物形貌特征的影响, 重点研究了F-离子对产物形貌特征、振实密度的影响. 利用前述产物通过高温固相合成法制备了高密度的LiMn0.45Ni0.45Co0.1O2和LiMn0.45Ni0.45Co0.1O1.96F0.04正极材料, 并研究了F元素掺杂对循环性能的影响. 结果表明, 在沉淀体系中加入F-, 可以改善产物的形貌特征和振实密度. SEM 测试结果表明, 产物具有良好的形貌; XRD测试表明, 产物具有良好的层状结构, 无杂质相存在. 在充放电电压区间为2.8-4.4 V, 电流密度为30 mA·g-1 时, LiMn0.45Ni0.45Co0.1O2和LiMn0.45Ni0.45Co0.1O1.96F0.04首次放电容量均为157 mAh·g-1, 经过50 次循环, 放电容量保持率分别为72.6%和86.0%, F元素的掺杂可以明显改进材料的循环性能.

Preparation Conditions of LiMn0.45Ni0.45Co0.1O2 via Hydroxide Co-precipitation

Ni0.45Co0.1Mn0.45(OH)2was prepared via improved hydroxide co-precipitation. The effect of reaction condition on the shape of the product, and the effect of F- ion on the morphology and tap-density of the product were studied. LiMn0.45Ni0.45Co0.1O2 and LiMn0.45Ni0.45Co0.1O1.96F0.04 were prepared by mixing this metal hydroxide with 5% excess LiOH followed by heat-treatment. The effect of F doping on the cycling performance of the prodct was investigated. The morphology and tap-density of the product were improved through the addition of F- in co-precipitation system. The product was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and charge-discharge tests. It can be seen from the SEMresults that the product has a good shape. The XRD studies showed that the material had a well-ordered layered structure without impurity phase. The initial capacities of both LiMn0.45Ni0.45Co0.1O2 and LiMn0.45Ni0.45Co0.1O1.96F0.04 are 157 mAh·g-1 at a charging potential between 2.8 and 4.4 V and a current density of 30 mA·g -1. The 72.6% and 86.0% discharge capacities were retained at the end of 50 charge-discharge cycles, respectively. It is shown that the F doping can obviously improve the cycling performance of the product.