水热合成Ni掺杂LiMnPO_4/C及其电化学性能研究  

Investigation on Hydrothermal Synthesis and Electrochemical Performance of Ni Doped LiMnPO_4/C Cathode Material

作　　者：张俊[1,2] 罗绍华 翟玉春[1,4] 汪应玲 黄红波[1,2] 刘彩玲 李贤 郝爱民 

机构地区：[1]东北大学冶金学院,辽宁沈阳110004 [2]河北省电介质与电解质功能材料重点实验室,河北秦皇岛066004 [3]东北大学材料科学与工程学院,辽宁沈阳110004 [4]东北大学秦皇岛分校资源与材料学院,河北秦皇岛066004

出　　处：《陶瓷学报》2017年第5期641-645,共5页Journal of Ceramics

基　　金：国家自然科学基金(51472167)

摘　　要：以PEG-400为溶剂和碳源,水热法合成Ni掺杂LiMn_(1-x)Ni_xPO_4/C正极材料。采用XRD、SEM、BET、充放电和循环伏安测试等材料和电化学性能表征和测试手段,研究了不同Ni掺杂量对LiMnPO4/C晶体结构、微观形貌及电化学性能的影响规律。结果表明,Ni掺杂后样品没有改变纯相LiMnPO4的物相结构,掺杂能减少晶粒尺寸,一次粒径50-100nm,呈类球形分散均匀。Ni掺杂量0,0.04,0.08,0.12mol.%,0.05C倍率对应首次放电比容量123.7mAh/g,138.6mAh/g,145.1mAh/g和129.1mAh/g;循环20周,比容量为111.3mAh/g,128.3mAh/g,138.9mAh/g和121.8mAh/g;容量保持率为89.98%,92.57%,95.72%和94.35%。LiMn_(0.92)Ni_(0.08)PO_4/C正极材料具备较好的循环性能和倍率性能,在0.05C,0.1C,0.5C和1C倍率下对应的首次放电比容量为145.1mAh/g,143.8mAh/g,140.2mAh/g和136.9mAh/g。掺杂后样品的循环可逆性得到改善,抑制了材料嵌脱锂过程中的极化现象。The olivine-type Li Mn1-xNixPO4/C cathode materials have been synthesized by hydrothermal method using PEG-400 as solvent and carbon source. The effects of Ni doping contents LiMnPO_4/C are investigated systematically by experimental research including XRD, SEM, charge-discharge tests and CV analysis on the crystal structure, micromorphology and electrochemical properties. The results indicate that the sample has spherical-like particles with the primary particles size ranging from 50-100 nm. At 0.05 C rate, the initial discharge capacities of LiMn_（1-x）Ni_xPO_4/C（x=0, x=0.04, x=0.08, x=0.12） are 123.7 m Ah/g,138.6 m Ah/g, 145.1 m Ah/g and 129.1 m Ah/g, respectively. After 20 cycles, the capacities decrease to 111.3 m Ah/g, 128.3 m Ah/g, 138.9 m Ah/g and 121.8 m Ah/g with the capacities retention of 89.98%, 92.57%, 95.72% and 94.35%. Among all the doped samples, LiMn_（0.92）Ni_（0.08）PO_4/C shows better cyclic performance and rate capability with the discharge capacity of 145.1 m Ah/g,143.8 m Ah/g, 140.2 m Ah/g and 136.9 m Ah/g at 0.05 C, 0.1 C, 0.5 C and 1 C in order. The cycle reversibility of doped samples improve, and restrain the polarization phenomenon in the lithium ions intercalation/deintercalation process.

关 键 词：锂离子电池 磷酸锰锂 镍掺杂 水热法 倍率性能 

分 类 号：TQ174.75[化学工程—陶瓷工业]