SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2021, Vol. 33 ›› Issue (5): 327-336.DOI: 10.1016/j.cjche.2020.09.017

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Influence of synergistic effect of LiNi0.8Co0.15Al0.05O2@Cr2O5 composite on the electrochemical properties

Yunke Wang1,2, Yongjia Li3, Yenan Zhang1,2, Guozheng Zha1,2, Feng Liang1,2, Yongnian Dai1,2, Yaochun Yao1,2   

  1. 1 The National Engineering Laboratory for Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China;
    2 Engineering Laboratory for Advanced Battery and Materials of Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China;
    3 Faculty of Metallurgy and Mining, Kunming Metallurgy College, Kunming 650033, China
  • Received:2020-06-11 Revised:2020-07-23 Online:2021-08-19 Published:2021-05-28
  • Contact: Yaochun Yao
  • Supported by:
    This work was financially supported by the National Natural Science Foundation of China (52064031), the Program for Innovative Research Team in the University of Ministry of Education of China (IRT_17R48) and National Natural Science Foundation of China (51674129). The authors sincerely acknowledge the anonymous reviewers for their insights and comments to further improve the quality of the manuscript.

Influence of synergistic effect of LiNi0.8Co0.15Al0.05O2@Cr2O5 composite on the electrochemical properties

Yunke Wang1,2, Yongjia Li3, Yenan Zhang1,2, Guozheng Zha1,2, Feng Liang1,2, Yongnian Dai1,2, Yaochun Yao1,2   

  1. 1 The National Engineering Laboratory for Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China;
    2 Engineering Laboratory for Advanced Battery and Materials of Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China;
    3 Faculty of Metallurgy and Mining, Kunming Metallurgy College, Kunming 650033, China
  • 通讯作者: Yaochun Yao
  • 基金资助:
    This work was financially supported by the National Natural Science Foundation of China (52064031), the Program for Innovative Research Team in the University of Ministry of Education of China (IRT_17R48) and National Natural Science Foundation of China (51674129). The authors sincerely acknowledge the anonymous reviewers for their insights and comments to further improve the quality of the manuscript.

Abstract: LiNi0.8Co0.15Al0.05O2 (NCA)@Cr2O5 composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr2O5, playing a synergistic role in improving the cyclic stability, initial discharge capacity and the security of low cut-off voltage (2.0 V). When the mass ratio of Cr2O5 in NCA is 45% (mass), the capacity retention rate increases from 58.5% without Cr2O5 to 69.3% in the range of 2.0-4.3 V. The initial discharge capacity of NCA@Cr2O5 composite material is 211.4 mA·h·g-1, its first coulombic efficiency is 94.2%, and the charging capacity remains approximately constant when mixed with 15% (mass) Cr2O5. The reason for the improvement of the initial charge-discharge efficiency (ICDE) was explained. Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements. Compared with NCA cathode material, the NCA@Cr2O5 composite material can provide not only additional stable sites and channels for Li+ insertion/extraction to make up for the loss of active Li+ sites and prevent the accumulation of Li+ in the circulation process, but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr2O5 nanoparticles adhering to NCA interface.

Key words: NCA@Cr2O5 composite, Cathode material, Synergistic effect, Electrochemical properties, Low voltage

摘要: LiNi0.8Co0.15Al0.05O2 (NCA)@Cr2O5 composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr2O5, playing a synergistic role in improving the cyclic stability, initial discharge capacity and the security of low cut-off voltage (2.0 V). When the mass ratio of Cr2O5 in NCA is 45% (mass), the capacity retention rate increases from 58.5% without Cr2O5 to 69.3% in the range of 2.0-4.3 V. The initial discharge capacity of NCA@Cr2O5 composite material is 211.4 mA·h·g-1, its first coulombic efficiency is 94.2%, and the charging capacity remains approximately constant when mixed with 15% (mass) Cr2O5. The reason for the improvement of the initial charge-discharge efficiency (ICDE) was explained. Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements. Compared with NCA cathode material, the NCA@Cr2O5 composite material can provide not only additional stable sites and channels for Li+ insertion/extraction to make up for the loss of active Li+ sites and prevent the accumulation of Li+ in the circulation process, but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr2O5 nanoparticles adhering to NCA interface.

关键词: NCA@Cr2O5 composite, Cathode material, Synergistic effect, Electrochemical properties, Low voltage