摘要
采用流变相法合成得到Li_(1.2+x)Ni_(0.1)Co_(0.2)Mn_(0.05)O_2(x=0, 0.036, 0.060, 0.096),探讨过锂量对结构和电化学性能的影响。X射线衍射(XRD)对样品进行结构分析证明所有样品具有典型的α-NaFeO_2结构和较小的阳离子混排度。扫描电镜(SEM)对样品进行表征证明不同过锂量的材料,颗粒相对均匀,表面光滑。电化学性能测试结果表明:最佳过锂量为x=0.036时,正极材料Li_(1.236)Ni_(0.1)Co_(0.2)Mn_(0.5)O_2在0.05C、2～4.8V测试条件下进行电化学性能测试,25和55℃下该材料初始放电容量分别为215.3和297.1 mAh·g-1,首次库伦效率分别为66.6%和84.6%,0.2 C下循环50次后容量保持率分别为89.0%和87.8%,且x=0.036时该材料具有最佳的倍率性能。
The Li-rich manganese-based cathode of Li1.2+xNi0.1Co0.2Mn0.5O2(x=0,0.036,0.060,0.096)was synthesized by a rheological phase method.The effect of extra lithium amount on the structure and electrochemical properties was discussed.X-ray diffraction(XRD)analysis indicates that all samples have typicalα-NaFeO2 structure and small cationic mixing degree.Scanning electron microscope(SEM)observation shows that the materials with different amounts of extra lithium exhibit relatively uniform particles and smooth surface.The result of electrochemical tests show that the material with an optimal amount of extra lithium(x=0.036)achieves the best electrochemical performance.The testing of electrical performance between 2~4.8 V at 0.05 C shows that the initial discharge capacity is up to 215.3mAh·g-1 at 25°C with the initial efficiency of 66.6%and 297.1 mAh·g^-1 at 55°C with the initial efficiency of 84.6%.After 50 cycles at 0.2C,the capacity retention is 89.0%at 25°C and 87.8%at 55°C.And when x=0.036,the material has the best rate performance.
作者
王征荣
张海朗
Wang Zhengrong;Zhang Hailang(Jiangnan University,Wuxi 214122,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2019年第3期941-946,共6页
Rare Metal Materials and Engineering
