Enhanced Electrochemical Performances of LiFePO₄/C Cathode Materials by Deposited with Ge Film

Abstract:

LiFePO₄/C-Ge electrodes were prepared with vacuum thermal evaporation deposition by depositing Ge films on as-prepared LiFePO₄/C electrodes. The effect of Ge film on the electrochemical performances of LiFePO₄/C cells was investigated systematically by charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. It was found that Ge-film-surface modified LiFePO₄/C showed excellent electrochemical performances compared to that of the pristine one in terms of cyclability and rate capability. At 60°C, LiFePO₄/C-Ge film exhibited outstanding cyclability with less than 5% capacity fade after 50 cycles while the pristine one suffers 15%. Analysis from the electrochemical measurements showed that the presence of Ge film on the LiFePO₄/C electrode would protect active material from HF generated by the decomposition of LiPF₆ in the electrolyte and stabilize the surface structure of active material during the charge and discharge cycle. Electrochemical impedance spectroscopy (EIS) results indicated that Ge film mainly reduced the charge transfer resistance R_ct of LiFePO₄/C electrode, resulting from the suppression of the solid electrolyte interfacial (SEI) film.

• Periodical: Advanced Materials Research (Volume 936)
• Pages: 480-485
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.936.480
• Online since: June 2014
• Authors: Yan Dan Huang*, Ying Bin Lin, Zhi Gao Huang
• Keywords: Ge Film, LiFePO₄, Li-Ion Battery, Rate Capability

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