摘要
富锂锰材料具有高的比容量和充放电电压平台,但不可逆容量较大。本文通过对富锂锰正极材料进行W掺杂,增强了过渡金属与氧的键合作用,抑制了材料首次充放电过程中晶格氧的脱出,同时,XRD精修结果表明W掺杂增大了富锂锰层状材料结构的层间距,促进了锂离子的扩散,降低了材料的电化学阻抗,有效改善了材料的循环稳定性和倍率性能。电化学测试发现W掺杂量为3%时性能较优,在0.2、3、5 C放电比容量分别为211.3、132.6、114.61 mAh/g,与未掺杂富锂锰材料的充放电容量相比,分别提高了10.5%、7.8%、12.58%。
Lithium-rich manganese materials have high specific capacity and charge-discharge voltage platform,but large irreversible capacity.The bonding between transition metals and oxygen was enhanced by W doping in lithium-rich manganese cathode materials,with inhibited lattice oxygen shedding during the first chargedisc harge process.Meanwhile,XRD refinement results showed that W-doping increased the interlayer spacing of lithium-rich manganese layered materials,promoted the diffusion of lithium ions,reduced the electrochemical impedance of materials,with an effective improvement of the cycle stability and rate performance of materials.Electrochemical tests show that the performance is the most favorable when W is doped at 3%,and the discharge specific capacities at 0.2 C,3 C and 5 C are 211.3 mAh/g,132.6 mAh/g and114.61 mAh/g,respectively,which are 10.5%,7.8%and 12.58%higher than those of undoped lithium-rich manganese materials.
作者
刘志亮
李小林
雷超
李栋
王春香
陈敬波
钟盛文
LIU Zhiliang;LI Xiaolin;LEI Chao;LI Dong;WANG Chunxiang;CHEN Jingbo;ZHONG Shengwen(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China)
出处
《有色金属科学与工程》
CAS
2020年第6期57-63,共7页
Nonferrous Metals Science and Engineering
基金
国家自然科学基金资助项目(21865012,51764008)
江西省教育厅资助项目(GJJ190432,GJJ190428)。
关键词
层状正极
掺杂
低阻抗
循环稳定性
layered cathode
doping
low impedance
cyclic stability
