Improvement of electrochemical performance of the Li9V3(P2O7)3(PO4)2 cathode material by aliovalent Mo4+ doping

作者:Duan, He; Wang, Zhen; He, Bin; Zhang, Jun; Yao, Heng; Zhao, Yanming; Fan, Qinghua; Kuang, Quan; Dong, Youzhong*
来源:JOURNAL OF SOLID STATE ELECTROCHEMISTRY, 2021, 25(3): 983-991.
DOI:10.1007/s10008-020-04873-y

摘要

Attributed to the realization of the multielectron transfers, with a stable 3D framework, Li9V3 (P2O7)(3)(PO4)(2) is considered an excellent cathode material, which can reversibly extract/insert nearly 5 mol Li. However, the poor intrinsic electronic conductivity and the low lithium diffusion coefficient limited its practical electrochemical ability. Considering the poor intrinsic electronic conductivity of the pristine Li9V3(P2O7)(3)(PO4)(2) compound, the introduction of one extra electron by replacing V3+ with aliovalent Mo4+ ions increases the concentration of the electronic charge carriers from Li9V3(P2O7)(3)(PO4)(2) and thus improves the electronic conductivity. At the same time, the larger ionic radius of Mo4+ leads to the increasement of the cell volume of the Li9V3(P2O7)(3)(PO4)(2) sample and thus facilitates Li+ transport into the structure. As a result, the electrochemical performances of the Li9V3(P2O7)(3)(PO4)(2) were improved obviously by a small amount of Mo. Especially for the Li9V3-xMox(P2O7)(3)(PO4)(2) (x = 0.02) sample, the electrode present the highest specific capacity herein and an excellent rate performance which is a promising cathode for lithium ion battery application.

  • 单位
    广东工业大学