摘要
采用沉淀法对层状LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2正极材料进行Y_2O_3表面包覆,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、电化学交流阻抗(EIS)及恒流充放电对所制备材料的结构、形貌及电化学性能进行表征。结果表明,Y_2O_3均匀包覆在LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2材料的表面,并没有改变材料的晶体结构,且Y_2O_3包覆的正极材料表现出良好的电化学性能。在2.5~4.5 V电压范围和20 mA/g电流密度下,包覆0.5%Y_2O_3材料的首次放电容量190.5 mAh/g,50次循环后,材料的容量保持率达到99.9%,而未包覆材料的首次放电容量略低(187.0 mAh/g),且容量衰减较快,50次循环后,材料的容量保持率仅有92.7%。此外,包覆0.5%Y_2O_3的材料在400 mA/g下放电容量仍有150 mAh/g,表现出优异的倍率性能。
Abstract： Y203-coated LiNi0.5 Co0.3Mn0.3O2 cathode materials were prepared by precipitation method. The structures, morphologies and electrochemical properties were characterized by X-Ray diffraction （XRD）, scanning electron microscopy （SEM） , electrochemical impedance spectroscopy （EIS） and galvanotactic charge-discharge test. The results indicate that Y2O3 are coated uniformly on the surface of LiNi0.5Co0.2- Mn0.3O2,and have no effect on the crystal structure of LiNi0.5 Co0.2-Mn0.3O2. The Y2 O3-coated LiNi0.5 C0.2Mn0.3O2 materials exhibit excellent electrochemical performance. The LiNi0.5Co0.2Mn0.3O2 materials coated with 0.5% Y203 shows initial discharge capacity of 190.5 mAh/g at the rate of 20 mA/g in the voltage range of 2.5 -4.5 V ,the capacity retention ratio is 99.9% after 50 cycles. While the initial dis- charge capacity of the bared materials is slightly lower （187.0 mAh/g） and rapid capacity fade occurs during the following cycles ,and the capacity retention ratio is 92.7% after 50 cycles. The discharge capaci- ties of the LiNi0.5Co0.2Mn0.3O2 material coated with 0.5% Y2O3 is 150 mAh/g,with good rate capability.
出处
《应用化工》
CAS
CSCD
北大核心
2017年第4期681-684,共4页
Applied Chemical Industry
基金
贵州省科技计划([2014]7002号
[2016]2310号)
贵州省高层次人才科研条件特助经费(TZJF-2010-047)
