(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 以LiOH·H2O、FeC2O4·2H2O和P2O5為原料，以草酸鈮為添加劑，采用反應(yīng)擠出法合成Li1−5xNbxFePO4/C材料；采用X射線衍射(XRD)、掃描電鏡(SEM)、循環(huán)伏安(CV)和充放電測試研究不同Nb5+摻雜量對Li1−5xNbxFePO4/C材料結(jié)構(gòu)、形貌以及電化學(xué)性能的影響。結(jié)果表明，適量的Nb5+摻雜不會(huì)改變材料的結(jié)構(gòu)和形貌；Nb5+摻雜可以有效減小電極的極化，其中Li0.97Nb0.006FePO4/C表現(xiàn)出最佳的電化學(xué)性能，在0.2C、0.5C、1C和2C倍率下的首次放電比容量分別為162.9、148.9、141.7和137.1 mA·h/g；材料循環(huán)性能良好，經(jīng)10次循環(huán)后，材料的放電比容量都保持在99%以上。
關(guān)鍵字: 鋰離子電池；磷酸鐵鋰；反應(yīng)擠出；Nb摻雜
（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
