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投稿时间:2020-11-04 修订日期:2020-11-12
投稿时间:2020-11-04 修订日期:2020-11-12
中文摘要: 采用溶胶—凝胶法制备了Na和Mg共掺杂的无钴富锂锰基正极材料,通过透射电子显微镜(HRTEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、充放电测试仪和电化学工作站对所制备样品的形貌、结构和电化学性能进行了测试。结果表明,所有样品颗粒大小约100 nm,呈近似球形,样品均无杂相峰出现,都具有良好的层状结构,Na+和Mg2+对Ni和Mn离子的氧化状态没有影响。LNi018具有最好的电化学性能,初始放电容量为225.5 mAh/g,库伦效率为78.0%,循环250周后容量保持率为83.1%。LNi018样品中Ni含量相对于其它样品较少,Ni2+和Mg2+的价态相同,离子半径近似(Ni2+ 6.9 nm,Mg2+ 7.2 nm),在晶格中Mg2+取代了Ni2+的位置,同时较大半径的Na+(10.2 nm)增大锂层间距,使晶体结构在充放电循环过程中更加稳定,因而能保持较高的放电电压和容量。
Abstract:Cobalt free Li-rich manganese based cathode materials with Na and Mg co-doping were prepared by sol-gel method. Morphology, microstructure and electrochemical properties of cobalt free Li-rich manganese based cathode materials were tested by transmission electron microscopy (HRTEM), X ray diffractometer (XRD), X ray photoelectron spectroscopy (XPS), charge discharge tester and electrochemical workstation. The results show that particle size of all samples is about 100 nm with near-spherical. There are no heterophase peaks in samples, all of them have good layered structure, and Na+ and Mg2+ has no effect on oxidation state of Ni and Mn ions. LNi018 has best electrochemical performance with initial discharge capacity of 225.5 mAh/g and coulombic efficiency of 78.0%, and capacity retention rate is 83.1% after 250 cycles. Ni content in LNi018 sample is less than that of other samples, valence states of Ni2+ and Mg2+ are the same, and ionic radius is approximate (Ni2 + 6.9 nm, Mg2+ 7.2 nm), Mg2+ takes place of Ni2+ in lattice. At the same time, the larger radius of Na+ (10.2 nm) rises lithium layer spacing, which makes crystal structure more stable during charge discharge cycle, thus maintaining a higher discharge voltage and capacity.
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基金项目:国家自然科学基金资助项目(51871190,51901201);河南省教育厅高等学校重点资助项目(19A610008、20B430015)
作者 | 单位 | |
李伟伟* | 新乡学院 化学与材料工程学院 | lww1873851@163.com |
张婷 | 新乡学院 化学与材料工程学院 | |
刘慧 | 新乡学院 化学与材料工程学院 | |
姚路 | 新乡学院 化学与材料工程学院 | |
司江菊 | 新乡学院 化学与材料工程学院 | |
李鹏发 | 新乡学院 化学与材料工程学院 | |
郎五可 | 新乡学院 化学与材料工程学院 |
Author Name | Affiliation | |
LI Wei-wei | College of Chemistry and Chemical Engineering,Xinxiang University,Xinxiang Henan | lww1873851@163.com |
ZHANG Ting | ||
LIU hui | ||
YAO Lu | ||
SI Jiang-ju | ||
LI Peng-fa | ||
LANG Wu-ke |
引用文本:
李伟伟,张婷,刘慧,姚路,司江菊,李鹏发,郎五可.Mg和Na共掺杂对富锂正极材料结构和电性能影响研究[J].有色金属(冶炼部分),2021(4):84-89.
LI Wei-wei,ZHANG Ting,LIU hui,YAO Lu,SI Jiang-ju,LI Peng-fa,LANG Wu-ke.Effect of Mg and Na Co-doping on Structure and Electrochemical Performance of Li-rich Cathode Materials[J].Nonferrous Metals (Extractive Metallurgy),2021(4):84-89.
李伟伟,张婷,刘慧,姚路,司江菊,李鹏发,郎五可.Mg和Na共掺杂对富锂正极材料结构和电性能影响研究[J].有色金属(冶炼部分),2021(4):84-89.
LI Wei-wei,ZHANG Ting,LIU hui,YAO Lu,SI Jiang-ju,LI Peng-fa,LANG Wu-ke.Effect of Mg and Na Co-doping on Structure and Electrochemical Performance of Li-rich Cathode Materials[J].Nonferrous Metals (Extractive Metallurgy),2021(4):84-89.