摘要
采用高温固相熔融加压法合成LiNiO_2正极材料,研究了助熔剂LiNO_3的加入量和反应体系中O_2压力对材料的结构和放电容量的影响．结果表明,随着LiNO_3加入量的增加,产物容量先增加后减小,LiOH和LiNO_3摩尔比0．9:0．1时产物结构和容量性能最佳;增大反应体系中O_2压力,产物结构和放电容量均得到改善．对LiNiO_2进行循环性能检测,30次循环后放电容量保持率为81．8%,晶型保持很好,相变反应特征变得明显,但是充电平台电位降低．采用交流阻抗技术计算知Li^+在Li_xNiO_2活性材料中的扩散系数在10^(-9)cm^2s^(-1)数量级,扩散系数较大,因而在充放电过程中Li^+迁移扩散更容易,材料电化学活性提高．
LiNiO2 cathod material was prepared through high-temperature solid-state melting pressuring method. The effects of LiNO3 addition and O2 pressure in reaction system on the structures and the discharge capacities of LiNiO2 products were investigated. The results showed that with the increasing of LiNO3 addition, discharge capacities of LiNiO2 products increased at first and then decreased. When the molar ratio of Li0H and LiNO3 is 0.9：0.1, the structure and discharge capacity are optimal. With the increasing of O2 pressure, structure and discharge capacity of LiNiO2 products were improved. Capacity conservation rate of LiNiO2 after 30 cycles is 81.8%, structure is keeped very well, phase transformations are obvious, but the flat voltage in charge process decreased. Diffusion coefficients of Li^＋ in LixNiO2 calculated through AC method are at 10^-9cm^2s^-1 order, they are upper, which indicates that the transfer and diffusion of Li^＋ are easier during charge-discharge process, the electrochemical activity of material increases.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2007年第1期97-101,共5页
Chinese Journal of Materials Research
基金
辽宁省科技厅基金资(2003224005)助项目.
关键词
无机非金属材料
锂离子电池
正极材料LiNiO2
高温固相熔融加压法
电化学性能
扩散系数
inorganic non-metauic materias, Li-ion batteries, cathode material LiNiO2, high- temperature solid-state melting pressuring method, electrochemical property, diffusion coefficient
