(湖南大學(xué) 化學(xué)化工學(xué)院，長(zhǎng)沙 410082)
摘 要: 以H3PO4、FeSO4·7H2O和LiOH·H2O為原料，石墨烯為碳源，采用水熱合成法制備鋰離子電池正極材料LiFePO4，考察水熱反應(yīng)溫度和后期的焙燒溫度等工藝條件對(duì)合成產(chǎn)物結(jié)構(gòu)、形貌及電化學(xué)性能的影響。結(jié)果表明，水熱反應(yīng)溫度和焙燒溫度對(duì)合成的LiFePO4形貌結(jié)構(gòu)與電化學(xué)性能均有顯著的影響，石墨烯的摻入可明顯改善材料的電化學(xué)性能。當(dāng)水熱溫度為150 ℃、焙燒溫度為700 ℃、石墨烯的摻入量為3%(質(zhì)量分?jǐn)?shù))時(shí)，制備的樣品具有相對(duì)較好的電化學(xué)性能，0.1C倍率下首次放電比容量為134.0 mA·h/g，經(jīng)過20次循環(huán)后的比容量為131.3 mA·h/g，容量衰減率僅為2.02%。
關(guān)鍵字: 鋰離子電池；水熱合成；磷酸鐵鋰；摻雜
（College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China）
Abstract:LiFePO4 cathode material was synthesized using H3PO4, FeSO4·7H2O and LiOH·H2O as raw materials and graphene as carbon source. The effects of hydrothermal temperature and calcination temperature on the structure, micro-morphology and electrochemical performance of the as-synthesized specimens were investigated. The results show that both of hydrothermal temperature and calcination temperature are crucial parameters for the microstructure and electrochemical property of hydrothermal LiFePO4, the incorporation of graphene can significantly improve the electrochemical properties of the material. At the hydrothermal temperature of 150 ℃, the calcination temperature of 700 ℃ and the addition of graphene of about 3% (mass fraction), the as-obtained sample shows good electrochemical performance with initial specific discharge capacity of 134.0 mA·h/g at 0.1C, after 20 cycles, the specific capacity is 131.3 mA·h/g, and the decay rate is only about 2.02%.
Key words: lithium ion battery; hydrothermal synthesis; lithium iron phosphate; doping
