Improved electrochemical performance of LiNi_0.5?xRh_xMn_1.5O₄ cathode materials for 5 V lithium ion batteries via Rh-doping

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• 作者：P. Wu^a ; ^b ; X.L. Zeng^a ; ^b ; C. Zhou^a ; ^b ; G.F. Gu^a ; ^b ; D.G. Tong^a ; ^b ; ^{tongdongge@163.com}
• 关键词：Composite materials ; Sintering ; Electrochemical techniques ; Electrochemical properties
• 刊名：Materials Chemistry and Physics
• 出版年：2013
• 出版时间：15 March, 2013
• 年：2013
• 卷：138
• 期：2-3
• 页码：716-723
• 全文大小：1344 K

文摘

Rh-doped LiNi_0.5Mn_1.5O₄ has been prepared for the first time as the 5?V cathode materials of lithium ion batteries. The samples were characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma analysis and electrochemical measurements. The results indicated that the rate capability and cycling stability of LiNi_0.5Mn_1.5O₄ at 25 and 55?¡ãC was effectively improved by doping with 2 mol % Rh. At a 3000?mA?g^?1 (20?¡ãC) charge/discharge rate, the LiNi_0.48Rh_0.02Mn_1.5O₄ sample still delivered an initial discharge capacity of 92.4?mAh?g^?1 at 25?¡ãC. Furthermore, it maintained 83.6 % of its initial capacity after 300 cycles under a 150?mA?g^?1 current rate (1?¡ãC) at 55?¡ãC. These improvements were principally attributed to Rh-substitution, which not only enhanced the electronic conductivity and lithium ion diffusion ability of LiNi_0.5Mn_1.5O₄, but also suppressed the destruction of electrolyte during cycling. The thermal stability of LiNi_0.5Mn_1.5O₄ was also enhanced by Rh-doping.