Hierarchical LiFe0.98MII 0.02PO4/C (MII = Ni, Mn, Mg) composites via co-doping for lithium ion batteries

2018 International Conference on Civil and Hydraulic Engineering

土木建筑工程;水利工程

Zhang, Xiaohong^1 ; Xu, Xing^1 ; Dong, Hui^1 ; Xu, Yunlong^1 ; Zhao, Chongjun^1 ; Liu, Dong^2 ; Zhang, Yang^3 ; Chen, Jufeng^1 ; Xie, Miao^1

School of Materials Science and Engineering, East China University of Science and Technology, Shanghai

200237, China^1

Department of Material Science and Engineering, University of Texas at Arlington, Arlington

TX

76019, United States^2

Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai

200050, China^3

关键词: Discharge capacities;    Electrochemical activities;    Electrochemical impedance spectroscopy measurements;    Electrochemical performance;    Field emission scanning electron microscopes;    Galvanostatic charge/discharge;    Physicochemical property;    Raman spectroscopy measurements;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/189/3/032048/pdf
DOI  :  10.1088/1755-1315/189/3/032048

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

Hierarchical LiFe0.98MII 0.02PO4/C (MII = Ni, Mn, Mg) composites via co-doping with a variety of cations synthesized through carbothermal reduction assisted with spray pyrolysis are first studied. The physicochemical properties are characterized by X-ray diffraction (XRD), Elemental analyzer, Raman spectroscopy measurements, Field-emission scanning electron microscope (FE-SEM) and High-resolution transmission electron microscope (HR-TEM). The electrochemical performance is characterized via galvanostatic charge/discharge tests, Cyclic voltammetry (CV) test and Electrochemical impedance spectroscopy (EIS) measurement. The results show that successful co-doping with different substitution portfolios can stabilize the crystal structure. What's more, trace ions incorporated into LiFePO4 can also serve as catalyst for graphitization and crystal growth. Especially, among all the co-doped LiFe0.98MII 0.02PO4/C (MII = Ni, Mn, Mg) composites, LiFe0.98Ni0.01Mn0.01PO4/C exhibits the most outstanding electrochemical activities. The LiFe0.98Ni0.01Mn0.01PO4/C composite displays a high discharge capacity of ∼135 mAh/g at 1 C with the capacity retention close to 95% after 100 cycles. The much more excellent ratability and superior cyclability of LiFe0.98Ni0.01Mn0.01PO4/C might be ascribed to the synergistic effect of vicariant lithium phosphates, that is, LiFePO4, LiNiPO4 and LiMnPO4.