(中南大學 冶金科學與工程學院，長沙 410083)
摘 要: 采用分步碳包覆法合成LiFePO4/C復合材料。首先，將原料Fe2O3、NH4H2PO4和葡萄糖經(jīng)過固相反應合成Fe2P2O7/C復合材料，再將Fe2P2O7/C與前驅(qū)體Li2CO3、葡萄糖混合，通過二次碳包覆工藝合成LiFePO4/C復合材料，并考察合成溫度對LiFePO4/C復合材料電化學性能的影響。采用X射線衍射、掃描電鏡、差熱−熱重分析、電化學阻抗譜(EIS)和充放電測試對材料的性能進行表征。結(jié)果表明：以制取的Fe2P2O7/C為前驅(qū)體合成的LiFePO4/C復合材料具有較好的物理和電化學性能，材料的振實密度達1.26 g/m3，0.1C放電容量為158.3 mA•h/g，1C初次放電比容量達到140 mA•h/g。
關鍵字: LiFePO4/C復合材料；Fe2P2O7；鋰離子電池；正極材料
stepwise carbon-coating
（School of Metallurgy Science and Engineering, Central South University, Changsha 410083, China）
Abstract:LiFePO4/C composite was synthesized by stepwise carbon-coating. First, the precursor Fe2P2O7/C was obtained by solid state reaction with Fe2O3, NH4H2PO4 and glucose, then, LiFePO4/C was synthesized by mixing the precursor, Li2CO3 and glucose through stepwise carbon-coating process. The effect of synthesis temperature on the electrochemical performances of LiFePO4/C composites was studied. The product were characterized by XRD, SEM, DSC-TGA, EIS and charge-discharge test. The results show that the LiFePO4/C composites synthesized with Fe2P2O7 as the precursor have excellent physics and electrochemical performance, the tap density of product reaches 1.26 g/cm3, and it has discharge capacities of 158.3 mA•h/g at 0.1C and 140 mA•h/g at 1C.
Key words: LiFePO4/C composites; Fe2P2O7; lithium ion batteries; cathode materials
