Effect of Ce³⁺ doping on the properties of LiFePO₄ cathode material

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• 作者：Nannan ZHAO ((赵南南))^a ; Yongsheng LI ((李永胜))^a ; Xiaoke ZHI ((郅晓科))^a ; Li WANG ((王 丽))^a ; ^b ; ^c ; Xinxin ZHAO ((赵新新))^a ; Yamian WANG ((王亚勉))^a ; Guangchuan LIANG ((梁广川))^a ; ^b ; ^c ; ^{Liangguangchuan@hebut.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：lithium-ion battery ; cathode material ; LiFePO4 ; Ce-doping ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：34
• 期：2
• 页码：174-180
• 全文大小：885 K

文摘

LiFe_1-xCe_xPO₄/C cathode materials were synthesized by solid-state reaction method. The effects of various Ce-doping amounts on the microstructure and electrochemical performance of LiFePO₄/C cathode material were intensively investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge measurements and electrochemical impedance spectroscopy (EIS). The results indicated that Ce-doping did not destroy the lattice structure of LiFePO₄/C, while enlarged the lattice volume tailored the particle size, decreased charge transfer resistance, increased electrical conductivity and Li-ion diffusion rate of LiFePO₄/C, and thus markedly enhanced the electrochemical performance of the LiFePO₄/C. Electrochemical test results showed that the LiFe_0.9Ce_0.1PO₄/C sample exhibited the best electrochemical performance with initial specific capacity of 155.4 mAh/g at 0.2 C, the capacity retention ratios of 99.6% at 100 cycles at 1 C and delivered a discharge capacity of 160.1 (0.1 C), 156.6 (0.2 C), 151.2 (0.5 C), 147.6 (1 C), 140.7 (2 C) and 136.7 mAh/g (5 C), respectively, presented the best rate capacity among all the samples. EIS results demonstrated that the transfer resistance of the sample decreased greatly by doping an appropriate amount of Ce.