摘要
采用湿法球磨制备了锂离子电池用混合正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2/LiFePO_4。通过X射线衍射(XRD)和扫描电镜(SEM)表征了材料的结构和形貌,采用恒流充放电测试、循环伏安测试(CV)和电化学阻抗谱测试(EIS)方法研究了混合正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2/LiFePO_4的电化学性能。结果表明:混合正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2/LiFePO_4的晶体结构完好,碳包覆的纳米LiFePO_4颗粒较好地包覆在LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2表面。含质量分数15%LiFePO_4的混合正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2/LiFePO_4电化学性能优良,0.2C首次充放电比容量为181.40mAh·g^(–1),首次充放电效率为90.79%;1.0C循环50次后放电比容量为169.89mAh·g^(–1),容量保持率为97.80%;3.0C循环5次后的放电比容量为162.22mAh·g^(–1),容量保持率仍有89.43%;60℃高温存储7d后,容量保持率和容量恢复率分别为86.48%和97.32%。
The LiNi0.5Co0.2Mn0.3O2/LiFePO4blend cathode material for lithium-ion battery was prepared by wet ball-milling.The crystalline structure and morphology of the sample were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM),and the electrochemical performances of LiNi0.5Co0.2Mn0.3O2/LiFePO4blend cathode material were investigated by galvanostatic charge/discharge,cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)tests.The results indicate that the crystalline structure of LiNi0.5Co0.2Mn0.3O2/LiFePO4are preserved well,and the LiNi0.5Co0.2Mn0.3O2is coated by LiFePO4nanoparticals.Among all the composite cathodes,theone with15%mass fraction of LiFePO4shows the best electrochemical performance.The initial discharge specific capacity of battery is181.40mAh·g–1at0.2C rate,and the first charge and discharge efficiency is90.79%.Its dischargespecific capacity is169.89mAh·g–1after50cycles at1.0C rate,with capacity retention of97.80%,and the discharge specific capacity is162.22mAh·g–1after5cycles at3.0C rate,with capacity retention of89.43%.After high temperature storaged for7days at60℃,the capacity retention rate and capacity recovery rate are86.48%and97.32%,respectively.
作者
何湘柱
胡燚
邓忠德
孔令涌
尚伟丽
HE Xiangzhu;HU Yi;DENG Zhongde;KONG Lingyong;SHANG Weili(School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006,China;Shenzhen Dynanonic Co., Ltd, Shenzhen 518055, Guangdong Province, China)
出处
《电子元件与材料》
CAS
CSCD
2017年第3期31-37,共7页
Electronic Components And Materials
