(中南大學 冶金科學與工程學院， 長沙 410083)
摘 要: 以FeSO4·7H2O， NH4H2PO4和H2O2為初始原料， 通過液相沉淀制得前驅(qū)體FePO4，然后通過碳熱還原得到LiFePO4/C。 X射線衍射和掃描電鏡分析表明： 560， 600， 700和800 ℃合成的樣品均為LiFePO4/C， LiFePO4顆粒粒徑隨合成溫度的升高而逐漸增大， 560 ℃合成材料的顆粒粒徑分布在0.3~0.4 μm之間； 而800 ℃合成材料的顆粒粒徑則達到0.6~0.7 μm， 反應剩余的碳黑直接分布在LiFePO4顆粒之間，有利于提高其電子導電率。 560 ℃樣品在放電倍率為0.1 C時的首次放電比容量為151 mA·h/g（0.1 C）， 而當放電倍率達到1 C時， 放電比容量為129 mA·h/g， 且具有良好的循環(huán)性能。
關鍵字: LiFePO4； 液相沉淀；碳熱還原； 前驅(qū)體
aqueous precipitation and
carbothermal reduction
WANG Zhi-xing, GUO Hua-jun
（School of Metallurgical Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: LiFePO4 was prepared by carbothermal reduction of FePO4 which was synthesized by aqueous precipitation from FeSO4·7H2O and NH4H2PO4 and hydrogen peroxide as the oxidizing agents. Samples were characterized by XRD and SEM. It is shown that the pure and homogenous LiFePO4 was successfully synthesized at 560, 600, 700 and 800 ℃, with average particle sizes about 0.3-0.4 μm for the material synthesized at 560 ℃ and 0.6-0.7 μm at 800 ℃. The residual carbon during processing was coated on LiFePO4, resulting in the enhancement of the material's electronic properties. The discharge capacity of the material synthesized at 560 ℃ is 151 mA·h/g at 0.1 C rate and 129 mA·h/g at 1 C rate.
Key words: LiFePO4; aqueous precipitation; carbothermal reduction; precursor
