水合肼对LIB正极材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2性能影响研究

Effects of hydrazine hydrate on electrochemical performance of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 cathode Materials for LIB

以NaOH和NH3.H2O为共沉淀剂,采用共沉淀法合成了前驱体Ni1/3Co1/3Mn1/3（OH）2,将前驱体与LiOH.H2O混合球磨,经过高温处理（500℃下预烧4h,然后在900℃下焙烧12h）得到锂离子电池（LIB）正极材料LiNi1/3Co1/3Mn1/3O2。考察了前驱体合成过程中还原剂水合肼对前驱体组成及正极材料电化学性能的影响,采用SEM观测前驱体的形貌,XRD分析正极材料粉末的层状结构并计算其晶胞参数,通过充放电实验测试LIB正极材料的电化学性能。结果表明,当水合肼浓度为0.48mol/L时,所得正极材料具有良好的电化学性能,在2.5~4.6V电压范围内及0.1和1C倍率下,其首次放电比容量分别为193.2和174.8mAh/g;1C倍率下经30次循环后其容量为164.6mAh/g,容量保持率为94.16%。

The precursor powders Ni1/3Co1/3Mn1/3（OH）2 were synthesized by co-precipitation with NaOH and NH3·H2O as chelating agent,and then LiNi1/3Co1/3Mn1/3O2 cathode material powders for lithium ion battery（LIB） were prepared from the mixture of Ni1/3Co1/3Mn1/3（OH）2 and LiOH·H2O,in which the mixture was grinded by a ball mill and then treated（pretreated at 500℃ for 4h and then calcined at 900℃ for 12h）.The effects of hydrazine hydrate on the composition of the precursor and the electrochemical performance of LiNi1/3Co1/3Mn1/3O2 cathode materials were investigated.The morphologies of the prepared precursor were characterized by scanning electron microscopy（SEM）,the structure of cathode material powders were confirmed by X-ray diffraction（XRD） and the lattice parameters were calculated,then the electrochemical performance of cathode material were tested by the charge and discharge measurement.The results showed that the cathode material shows better electrochemical property when the concentration of hydrazine hydrate were 0.48mol/L,with the first specific discharge capacity 193.2 and 174.8mAh/g at 0.1 and 1C,respectively,in the potential range of 2.5-4.6 V.And the capacity of 164.6 mAh/g was retained at the end of 30 charge-discharge cycle with capacity retention of 94.16 % at the density of 1C.