高镍LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)的锂离子导体Li_(3)PO_(4)的包覆改性及电化学性能研究  

Surface modification and electrochemical properties of Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) by Li^(+)-conductor Li_(3)PO_(4) coating

作　　者：王娟[1,2] 刘占荣 梁芳慧[1] 贾鹏飞 WANG Juan;LIU Zhanrong;LIANG Fanghui;JIA Pengfei(College of Chemical and Engineering, Shijiazhuang University, Shijiazhuang 050035, China;Technology Innovation Center of Hebei for Fiber Material, Shijiazhuang 050035, China)

机构地区：[1]石家庄学院化工学院,石家庄050035 [2]河北省纤维材料技术创新中心,石家庄050035

出　　处：《功能材料》2021年第3期3182-3187,共6页Journal of Functional Materials

基　　金：河北省重点研发计划资助项目(19211203D);河北省院士工作站建设专项资助项目(205A1201H);石家庄市化学纤维技术创新中心建设资助项目(198190167A)。

摘　　要：采用典型的溶胶-凝胶法,在高镍LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极颗粒表面包覆不同含量的Li_(3)PO_(4)锂离子导体。利用X射线衍射仪,扫描电镜对Li_(3)PO_(4)包覆前后的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)样品的晶体结构和微观形貌进行分析。结果表明,合成材料的层状结构明显,阳离子混排度低,并且Li_(3)PO_(4)成功包覆在LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)颗粒表面。另外,对4个样品进行了首次充放电,倍率放电和循环性能比较,结果表明经过Li_(3)PO_(4)包覆后的正极材料的综合电化学性能明显比未包覆样品优越。首次库伦效率从未包覆样品的84.2%提高到2%(质量分数)Li_(3)PO_(4)包覆样品的89.2%。而且在5C高倍率,2%(质量分数)Li_(3)PO_(4)包覆LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)的放电比容量是129.7 mAh/g,远远高于未包覆样品的92.6 mAh/g。同时,在常温和高温环境下循环100次后,2%(质量分数)Li_(3)PO_(4)包覆LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)的容量保持率比未包覆样品分别高出7.1%和9.9%。Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode materials are coated by the different contents of Li_(3)PO_(4) Li+-conductor via the typical Sol-Gel method.The crystal structure and micro-morphology of Li_(3)PO_(4) coated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) are investigated by the X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results indicate the prepared samples demonstrate the well layered structure and lower cation mixing degree.The Li_(3)PO_(4) is successfully covered on the surface of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2).In addition,the results of initial charging-discharging,rate capacity and cycling tests for the four samples demonstrate the cathodes after Li_(3)PO_(4) coating deliver the obvious enhanced electrochemical properties than that of the pristine one.The initial coulombic efficiency of pristine cathode could be enhanced from 84.2%to 89.2%when the Li_(3)PO_(4) coating content increases to 2 wt%.Moreover,the 2wt%Li_(3)PO_(4) coated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) delivers a discharge capacity of 129.7 mAh/g at 5 C high rate,much larger than that(92.6 mAh/g)of the pristine one.Meanwhile,the 2 wt%Li_(3)PO_(4) coated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) respectively demonstrates the capacity retention of 7.1%and 9.9%higher than those of the pristine cathode at 25℃and 45℃condition after 100 cycles.

关 键 词：LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) Li_(3)PO_(4)包覆 高倍率放电 优异循环稳定性 低电荷转移阻抗 

分 类 号：TM912[电气工程—电力电子与电力传动]