摘要
以复合锰氧化物为锰源前驱体,采用多段高温热处理工艺合成了尖晶石锰酸锂(LiMn_(2)O_(4)),采用X射线衍射(XRD)、扫描电镜(SEM)、电化学阻抗谱(EIS)和充放电测试等研究了其晶体结构、微观形貌和电化学性能。结果表明:随着类球形Mn_(3)O_(4)组分在复合锰源前驱体中的占比提高,合成的尖晶石锰酸锂的晶格常数增大,晶胞体积变大,综合电化学性能也随之提高。采用高比例类球形Mn_(3)O_(4)的复合锰源前驱体合成的尖晶石锰酸锂具有最优的电化学性能,在25℃、0.2C倍率条件下,初始放电克比容量为117.83 mAh/g,1C倍率条件下,常温循环150次后,容量保持率为97.98%,在10C高倍率条件下,放电克比容量仍有101.03 mAh/g,而采用纯电解二氧化锰(EMD)合成的锰酸锂放电克比容量仅有67.74 mAh/g。电化学阻抗谱分析结果表明,采用高比例类球形Mn_(3)O_(4)的复合锰源前驱体合成的尖晶石锰酸锂具有较好的循环可逆性和较大的锂离子扩散系数。
Spinel lithium manganate(LiMn_(2)O_(4))was synthesized by multi-stage high temperature heat treatment with complex manganese oxide as manganese source precursor,and crystal structure,microstructure and electrochemical properties of the LiMn_(2)O_(4)were studied by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS)and chargedischarge test.The results show that with the increase of the proportion of spherical-like Mn_(3)O_(4) in the complex manganese source precursor,the lattice constant of the LiMn_(2)O_(4) increases,the cell volume increases,and the comprehensive electrochemical performance also improves.The spinel lithium manganate synthesized from high proportion spherical-like Mn_(3)O_(4) complex manganese source precursor has the best electrochemical performance,under the conditions of 25℃and 0.2C,the initial specific discharge capacity is 117.83 mAh/g,under the condition of 1C,after 150 cycles at room temperature,the capacity retention rate is 97.98%,and under the condition of high rate of 10C,the specific discharge capacity is still 101.03 mAh/g,while the specific discharge capacity of the lithium manganate synthesized by pure electrolytic manganese dioxide(EMD)is only 67.74 mAh/g.The results of electrochemical impedance spectroscopy show that the the spinel lithium manganate synthesized from high proportion spherical-like Mn_(3)O_(4) complex manganese source precursor has good cyclic reversibility and large lithium ion diffusion coefficient.
作者
李春流
杨俊峰
朱金良
张临超
王先平
LI Chun-liu;YANG Jun-feng;ZHU Jin-liang;ZHANG Lin-chao;WANG Xian-ping(Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch,Graduate School of University of Science and Technology of China,Hefei 230026,China;Guangxi University,Nanning 530004,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2022年第4期27-33,共7页
Transactions of Materials and Heat Treatment
基金
广西崇左市科技计划项目(崇科FA2019001)。
关键词
正极材料
锰酸锂
循环性能
交流阻抗
anode material
LiMn_(2)O_(4)
cycling performance
electrochemical impedance spectroscopy
