(1. 北京科技大學 材料科學與工程學院，北京 100083；
2. 萊蕪市粉末冶金先進制造重點實驗室，山東 271100)
摘 要: 采用氧化−沉淀法，以FeSO4·7H2O、H3PO4和H2O2為原料通過合成球形前驅體FePO4·2H2O來制備高密度球形LiFePO4/C復合材料。結果表明：當溶質濃度為0.1 mol/L，攪拌速度為500 r/min，陳化時間為36 h時，可合成振實密度高、球形度好的球狀前驅體FePO4·2H2O；采用超聲波浸漬液法將制備的FePO4與LiOH·H2O、蔗糖混合，通過碳熱還原法合成球形LiFePO4/C。該球形LiFePO4/C正極材料的振實密度為1.68 g/cm3，在0.05 C、0.1 C和0.5 C倍率下的首次放電比容量分別為138.9、128.7和113.2 mA·h/g，經(jīng)20次循環(huán)后，容量的保持率分別為99％，98.7％和98.6%。
關鍵字: 氧化−沉淀法；LiFePO4/C；FePO4；球形；正極材料
（1. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China;
Key Laboratory of Powder Metallurgy in Advanced Manufacturing of Laiwu, Laiwu 271100, China）
Abstract:A high tap density LiFePO4/C composite material was prepared from spherical FePO4·2H2O powder via an oxygen-precipitation method by FeSO4·7H2O and H3PO4 with hydrogen peroxide as the oxidizing agent. The results show that, when the concentration of reactants is 0.1 mol/L, stirring speed is 500 r/min and deposite time is 36 h, the spherical FePO4·2H2O powders with high tap density and good sphericity are obtained. The original materials of FePO4, sucrose and LiOH·H2O are mixed by steep ultrasonic oscillation. Spherical anode materials LiFePO4/C are synthesized by carbothermal reduction method. The spherical LiFePO4/C cathode material with tap density of 1.68 g/cm3 achieves high initial discharge capacities of 138.9, 128.7 and 113.2 mA·h/g at 0.05 C, 0.1 C and 0.5 C rates, respectively, and after 20 cycles discharges, the capacity retention rates are 99%, 98.7% and 98.6%, respectively.
Key words: oxygen-precipitation method; LiFePO4/C; FePO4; spherical; cathode material
