(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 以LiOH·H2O、FeC2O4·2H2O和P2O5为原料，以草酸铌为添加剂，采用反应挤出法合成Li1−5xNbxFePO4/C材料；采用X射线衍射(XRD)、扫描电镜(SEM)、循环伏安(CV)和充放电测试研究不同Nb5+掺杂量对Li1−5xNbxFePO4/C材料结构、形貌以及电化学性能的影响。结果表明，适量的Nb5+掺杂不会改变材料的结构和形貌；Nb5+掺杂可以有效减小电极的极化，其中Li0.97Nb0.006FePO4/C表现出最佳的电化学性能，在0.2C、0.5C、1C和2C倍率下的首次放电比容量分别为162.9、148.9、141.7和137.1 mA·h/g；材料循环性能良好，经10次循环后，材料的放电比容量都保持在99%以上。
关键字: 锂离子电池；磷酸铁锂；反应挤出；Nb掺杂
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. School of Metallurgical Science and Engineering, Central South University，Changsha 410083, China）
Abstract:Li1−5xNbxFePO4/C material was synthesized by reaction extrusion using LiOH·H2O, FeC2O4·2H2O and P2O5 as raw materials and niobium oxalate as additive. The effects of Nb5+ content on the structure, morphology and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis and electrochemical tests. The results show that appropriately doping Nb5+ can reduce the electrode polarization effectively without serious effects on structure and morphology. Li0.97Nb0.006FePO4/C, exhibiting the best electrochemical properties, has initial discharge capacities of 162.9, 148.9, 141.7 and 137.1 mA·h/g at 0.2C, 0.5C, 1C and 2C rate, respectively, and the discharge capacities remain above 99% after 10 cycles.
Key words: Li-ion battery; lithium iron phosphate; reaction extrusion; Nb-doping
