锂离子电池正极材料Li_2FeSiO_4的合成及其性能  

Synthesis and characteristic of new cathode material Li_2FeSiO_4 for lithium-ion battery

作　　者：张勇[1,2] 高海丽[1] 王力臻[1,2] 贾晓磊[1] 宋延华[1] 

机构地区：[1]郑州轻工业学院材料与化学工程学院,河南郑州450002 [2]河南省表界面科学重点实验室,河南郑州450002

出　　处：《电源技术》2013年第12期2109-2111,2220,共4页Chinese Journal of Power Sources

基　　金：国家自然科学基金资助项目(21001097);河南省科技厅基础与前沿技术研究项目(102300410107);河南省高校科技创新人才支持计划资助项目(2012HASTIT022);河南省高等学校青年骨干教师资助计划项目(豫教高[2009]844号)

摘　　要：以铁源（FeC6HdD7·5H2O,FeC2O4·2H2O及FeS04·7H2O）、锂源（LiAC·2H2O，Li2CO3及LiOH·H2O）、柠檬酸和正硅酸乙酯（TEOS）为原料，采用溶胶一凝胶一微波辅助法合成新型锂离子电池正极材料Li2FeSiO4，并用X射线衍射（XRD）、扫描电子显微镜（SEM）、激光粒度分析及电化学测试等方法，优化了铁源、锂源、微波时间等合成条件。结果表明，以FeC2O4·2H2O为铁源，LiAC·2H20为锂源，柠檬酸加入量0．0225mol，微波时间9min合成的Li2FeSiO4正极材料属于单斜晶系，粒度大小分布比较均匀，且具有较高的放电比容量和较好的循环稳定性。在1．5～4.3V、0.1C下样品具有粒径小、交换电流密度大、电荷转移阻抗小等优点，首次放电比容量为60mAh／g，5次循环后比容量为47mAh／g。容量保持率为78．3%。Lithium-ion battery new cathode material Li2FeSiO, was synthesized by sol method using iron sources （FeC6H5O7-5 H2O, FEC2O4.2 H2O and FeSO4·2 H2O）,lithium sources （LiAC·2 H2O, Li2CO3 and LiOH-H2O）, citric acid and TEOS as the raw materials. Synthesized conditions including iron sources, lithium sources, and microwave time were optimized.Structure,morphology,particle size and electrochemical performance of the synthesized materials were studied by XRD, SEM, laser particle size determination and charge-discharge tests. The results show that Li2FeSiO4 prepared under the condition of FEC2O4-2 H2O as iron source, LiAC .2 H2O as lithium source, 0.022 5 mol for the citric acid addition and microwave time is 9 min has typical monoclinic structure with homogenous distribution of particle, high discharge capacity and better cycle stability. The material has the best electrochemical performance due to the smaller particles and lower charge-transfer resistance, which has 60 mAh/g initial discharge specific capacity under 0.1 C discharge rate,47 mAh/g specific capacity after 5 cycles with 78.3% capacity retention.

关 键 词：溶胶-凝胶-微波辅助法 激光粒度分析 LI2FESIO4 

分 类 号：TM912[电气工程—电力电子与电力传动]