高性能纳米针状Li_(2)FeSiO_(4)正极的合成及其电化学性能  

Synthesis of high performance nanoneedle Li_(2)FeSiO_(4) cathode and its electrochemical properties

作　　者：丁正平 李静 李俊鹏 林华辉 任玉荣 罗鲲 DING Zhengping;LI Jing;LI Junpeng;LIN Huahui;REN Yurong;LUO Kun(School of Materials Science&Engineering,Changzhou University,Changzhou Jiangsu 213164,China)

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164

出　　处：《电源技术》2024年第12期2350-2361,共12页Chinese Journal of Power Sources

基　　金：国家自然科学基金资助项目(52203291);常州市社会发展项目应用基础研究计划(CJ20210079);常州市领军型创新人才引进培育项目(CQ20210099)。

摘　　要：Li_(2)FeSiO_(4)材料结构中能进行两个锂离子的脱嵌反应,理论比容量高达330 mAh/g,是一种极具应用前景的正极材料。然而,其锂离子扩散速率和电子电导率极低,难以进行超过一个锂离子的脱嵌反应,电化学性能较差。基于锂离子在Li_(2)FeSiO_(4)结构中扩散的各向异性,提出了一种高效绿色的水热调控合成方法,合成得到一种具有晶面暴露特性的Li_(2)FeSiO_(4)材料,经过碳包覆改性后获得带晶面暴露特性的纳米针状Li_(2)FeSiO_(4)@C单晶复合材料。由于锂离子在晶面暴露结构中能快速迁移,所以该材料的电化学性能优异。0.1 C放电比容量达220.1 mAh/g,1 C下循环100次后容量保持率达到96%。Lithium iron orthosilicate(Li_(2)FeSiO_(4))is a cathode material with a theoretical specific capacity of 330 mAh/g,which can carry out the intercalation/deintercalation reaction of two Li+in the structure.However,its Li+diffusion rate and electron conductivity are extremely low,and it is difficult to carry out more than one Li+intercalation/deintercalation reaction,which makes its electrochemical performance very poor.Based on the anisotropy of Li+diffusion in the structure of Li2Fe‐SiO4,an efficient and green hydrothermally controlled synthesis method was proposed to synthesize a Li_(2)FeSiO_(4)material with specific exposed facet,and a nanoneedle-like Li_(2)FeSiO_(4)@C single crystal composite with crystal plane exposure characteristics was obtained after carbon coating modification.Due to the rapid migration of lithium ions in the specific exposed facet,the material has excellent electrochemical properties.The discharge specific capacity at 0.1 C is 220.1 mAh/g,and the capacity retention rate reaches 96%after 100 cycles at 1 C.

关 键 词：锂离子电池 正极材料 硅酸铁锂 水热合成法 晶面暴露 

分 类 号：TM912.9[电气工程—电力电子与电力传动]