期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2018
卷号：189
期号：3
页码：032048
DOI：10.1088/1755-1315/189/3/032048
语种：English
出版社：IOP Publishing
摘要：Hierarchical LiFe0.98MII0.02PO4/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 LiFe0.98MII0.02PO4/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.
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