Effects of Lib>2b>COb>3b> as a secondary lithium source on the LiFePOb>4b>/C composites prepared via solid-state method

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• 作者：Jinhan Yao ; Xiaotan Wu ; Pinjie Zhang ; Shuoshuo Wei ; Lianbang Wang ; ^{wanglb99@zjut.edu.cn}
• 关键词：A. Ceramics ; B. Chemical synthesis ; D. Electrical properties
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2012
• 期刊代码：69_00223697
• 类别：ch
• 出版时间：July, 2012
• 卷：73
• 期：7
• 页码：803-807
• 文件大小：616 K

摘要

Lib>2b>COb>3b> was used as the secondary lithium source for the synthesis of LiFePOb>4b>/C composites via a solid-state reaction method by adopting Lib>3b>POb>4b> as the main lithium source. The main purpose of using Lib>2b>COb>3b> is to compensate for the partial lithium loss during the sintering while reducing the usage of excess Lib>3b>POb>4b>. In this study, the effects of Lib>2b>COb>3b> amount on the phase, structural and electrochemical properties of LiFePOb>4b>/C material were systematically investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), constant-current charge-discharge test and cyclic voltammetry (CV). The results showed that by adding an appropriate amount of Lib>2b>COb>3b>, the impurities, e.g. Lib>3b>POb>4b>, normally appearing in the final product, could be excluded. It was found that LiFePOb>4b>/C with Lib>2b>COb>3b> in 6%excess (vs. stoichiometric LiFePOb>4b>) exhibited the best electrochemical performance, which delivered initial discharge capacities of 141.7, 125.2, 119.9 and 108.9 mAh g^鈭?, respectively, at 0.5, 1, 2 and 5C rates. The capacity was reduced to 113.4 mAh g^鈭? after 50 cycles at 2C rate, with capacity retention rate of 94.6%.