Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第20卷    第4期    总第133期    2010年4月

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文章编号:1004-0609(2010)04-0801-06
LiNi0.5Mn1.5O4/Ag复合材料的制备及其电化学性能
何则强12,熊利芝12,梁  凯1,卢  彪1

(1. 吉首大学 生物资源与环境科学学院,吉首 416000;
2. 中南大学 化学化工学院,长沙 410083
)

摘 要: 采用流变相法合成LiNi0.5Mn1.5O4粉末。以甲醛为还原剂,采用化学镀法制备LiNi0.5Mn1.5O4/Ag复合材料。通过X射线衍射分析、扫描电镜分析以及电化学测试等手段对LiNi0.5Mn1.5O4/Ag的微观结构、表面形貌和电化学性能进行研究。结果表明:在LiNi0.5Mn1.5O4/Ag中,LiNi0.5Mn1.5O4表面被包覆一层分散均匀且颗粒大小均匀的Ag,Ag颗粒的大小为200~300 nm。Ag颗粒的存在增加LiNi0.5Mn1.5O4颗粒之间的电子导电性,降低电池的极化作用,减少锰的溶解,使得LiNi0.5Mn1.5O4/Ag具有比LiNi0.5Mn1.5O4更高的可逆容量、更稳定的循环性能和更好的倍率性能。以0.2C放电时,LiNi0.5Mn1.5O4/Ag的首次放电容量达到143.8 mA∙h/g;而经100次循环后,以0.2C和2.0C放电时,LiNi0.5Mn1.5O4/Ag的容量保持率分别达到99.2%和86.8%。

 

关键字: 锂离子电池;LiNi0.5Mn1.5O4;银;包覆;化学镀

Preparation and electrochemical performances of
LiNi0.5Mn1.5O4/Ag composite
HE Ze-qiang1, 2, XIONG Li-zhi1, 2, LIANG Kai1, LU Biao1

1. College of Biology and Environmental Science, Jishou University, Jishou 416000, China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China

Abstract:LiNi0.5Mn1.5O4 powders were prepared by rheological method. LiNi0.5Mn1.5O4/Ag composite was prepared by electroless plating method using formaldehyde as reductant. The microstructure, surface morphology and electrochemical properties of LiNi0.5Mn1.5O4/Ag composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. The phase analysis shows that Ag particles with a uniform size of 200−300 nm are dispersed on the surface of LiNi0.5Mn1.5O4 instead of entering the spinel structure. According to the electrochemical tests results, it is clear to see that Ag additives efficiently improve the cycling stability, reversibility and high-rate discharge capacity of pristine LiNi0.5Mn1.5O4 by increasing the electrical conductivity between LiNi0.5Mn1.5O4 particles, decreasing the polarization of cathode and reducing the dissolution of Mn. The first discharge capacity of LiNi0.5Mn1.5O4/Ag composite is higher than 143.8 mA∙h/g at 0.2C. After cycling 100 times at 0.2C and 2.0C, the capacity retention of LiNi0.5Mn1.5O4/Ag composite are 99.2% and 86.8%, respectively.

 

Key words: Li ions battery; LiNi0.5Mn1.5O4; Ag; coating; electroless plating

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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