Li Ion Diffusivity and Improved Electrochemical Performances of the Carbon Coated LiFePO_4
Li Ion Diffusivity and Improved Electrochemical Performances of the Carbon Coated LiFePO_4
- 주제(키워드) Lithium iron phosphate , Carbon coating , Chemical diffusion coefficient , Cyclic voltammetry , Electrochemical impedance spectroscopy
- 발행기관 대한화학회
- 발행년도 2011
- 총서유형 Journal
- UCI G704-000067.2011.32.3.036
- KCI ID ART001536798
- 본문언어 영어
초록/요약
This study examines the effects of a carbon coating on the electrochemical performances of LiFePO_4. The results show that the capacity of bare LiFePO4 decreased sharply, whereas the LiFePO_4/C shows a well maintained initial capacity. The Li ion diffusivity of the bare and carbon coated LiFePO_4 is calculated using cyclic voltammetry (CV) to determine the correlation between the electrochemical performance of LiFePO4and Li diffusion. The diffusion constants for LiFePO_4 and LiFePO_4/C measured from CV are 6.56 × 10^(−16) and 2.48 × 10^(−15) cm^2 s^(−1), respectively, indicating considerable increases in diffusivity after modifications. The Li ion diffusivity (D_(Li)) values as a function of the lithium content in the cathode are estimated by electrochemical impedance spectroscopy (EIS). The effects of the carbon coating as well as the mechanisms for the improved electrochemical performances after modification are discussed based on the diffusivity data.
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