Abstract: LiMn1-xFexPO4 with the advantages of low cost, environmental amity, high energy density, good thermal stability as well as superior cycling stability, has a good application prospect for lithium-ion batteries. Among various methods for preparing LiMn1-xFexPO4, the high-temperature solid-state method has been widely used because of its simple process, low cost and high yield. However, the particle size of LiMn1-x-FexPO4 is not well-distributed by the high-temperature solid-state method and the particles are easy to aggregate. To solve these problems, the sucrose was used as carbon source to obtain secondary carbon-coated LiMn0.5Fe0.5PO4 material by an improved high-temperature solid-state method in this paper. The structure and the morphologies of the as-prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM). The results showed that the secondary carbon-coated LiMn0.5Fe0.5-PO4 had a single olivine phase and an average particle size of 260 nm. The electrochemical properties of the secondary carbon-coated LiMn0.5-Fe0.5PO4 were studied by galvanostatic charge-discharge method. The LiMn0.5Fe0.5PO4/C could deliver discharge capacities of 165 mAh/g, 132 mAh/g and 92 mAh/g at 0.1C, 1C, and 10C rate, respectively. The capacity retention was more than 90% after 100 cycles at 1C, showing the excellent rate capability and cyclability. In addition, the reason for the improved electrochemical properties of the secondary carbon-coated LiMn0.5Fe0.5PO4 had also been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements.
1 Deng Y F, Yang C, Zou K, et al. Advanced Energy Materials,2017,7, 1601958. 2 Yang W C, Bi Y J, Qin Y P, et al. Journal of Power Sources,2015,275,785. 3 Kim J K, Vijaya R, Zhu L, et al. Journal of Power Sources,2015,275,106. 4 Ye F, Wang L, He X, et al. Journal of Power Sources,2014,253,143. 5 Zhou X, Deng Y, Wan L, et al. Journal of Power Sources,2014,265,223. 6 Zhou X, Xie Y, Deng Y, et al. Journal of Materials Chemistry A,2015,3,996. 7 Kim M S, Kim H K, Lee S W, et al. Scientific Reports, 2016,6, 26686. 8 Shen H, Xiang W, Shi X, et al. Ionics,2015,22,193. 9 Wang Y, Wu C Y, Yang H, et al. Journal of Materials Chemistry A,2018,6,10395. 10 Wang K, Hou M, Yuan S, et al. Electrochemistry Communications,2015,55,6. 11 Xiang W, Wang E H, Chen M Z, et al. Electrochimica Acta,2015,178,353. 12 Xiang W, Zhong Y J, Ji J Y, et al. Physical Chemistry Chemical Phy-sics,2015,17,18629. 13 Yan S Y, Wang C Y, Gu R M, et al. Journal of Solid State Electroche-mistry,2015,19,2943.
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2020, Vol. 34 
