Li ion diffusivity and rate performance of the LiFePO4 modified by Cr doping

Chang Kyoo Park; Sung Bin Park; Ho Chul Shin; Won Il Cho; Ho Jang

doi:10.5012/bkcs.2011.32.1.191

Li ion diffusivity and rate performance of the LiFePO₄ modified by Cr doping

Chang Kyoo Park
, Sung Bin Park
, Ho Chul Shin
, Won Il Cho
, Ho Jang

Dept. of Materials Science & Engineering

Korea University
GS Caltex Corporation
Korea Institute of Science and Technology

Research output: Contribution to journal › Article › peer-review

32 Scopus citations

Abstract

This study reports the root cause of the improved rate performance of LiFePO₄ after Cr doping. By measuring the chemical diffusion coefficient of lithium (D_Li) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the correlation between the electrochemical performance of LiFePO₄ and Li diffusion is acquired. The diffusion constants for LiFePO₄/C and LiFe_0.97Cr _0.03PO₄/C measured from CV are 2.48 × 10 ^-15 and 4.02 × 10^-15 cm² s^-1, respectively, indicating significant increases in diffusivity after the modification. The difference in diffusivity is also confirmed by EIS and the D_Li values obtained as a function of the lithium content in the cathode. These results suggest that Cr doping facilitates Li ion diffusion during the charge-discharge cycles. The low diffusivity of the LiFePO ₄/C leads to the considerable capacity decline at high discharge rates, while high diffusivity of the LiFe_0.97Cr_0.03PO ₄/C maintains the initial capacity, even at high C-rates.

Original language	English
Pages (from-to)	191-195
Number of pages	5
Journal	Bulletin of the Korean Chemical Society
Volume	32
Issue number	1
DOIs	https://doi.org/10.5012/bkcs.2011.32.1.191
State	Published - 20 Jan 2011

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

Chemical diffusion coefficient
Cyclic voltammetry
Doping
Electrochemical impedance spectroscopy
Lithium iron phosphate

Access to Document

10.5012/bkcs.2011.32.1.191

Cite this

@article{963caf19c1ef42399ddf5babe491e502,

title = "Li ion diffusivity and rate performance of the LiFePO4 modified by Cr doping",

abstract = "This study reports the root cause of the improved rate performance of LiFePO4 after Cr doping. By measuring the chemical diffusion coefficient of lithium (DLi) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the correlation between the electrochemical performance of LiFePO4 and Li diffusion is acquired. The diffusion constants for LiFePO4/C and LiFe0.97Cr 0.03PO4/C measured from CV are 2.48 × 10 -15 and 4.02 × 10-15 cm2 s-1, respectively, indicating significant increases in diffusivity after the modification. The difference in diffusivity is also confirmed by EIS and the DLi values obtained as a function of the lithium content in the cathode. These results suggest that Cr doping facilitates Li ion diffusion during the charge-discharge cycles. The low diffusivity of the LiFePO 4/C leads to the considerable capacity decline at high discharge rates, while high diffusivity of the LiFe0.97Cr0.03PO 4/C maintains the initial capacity, even at high C-rates.",

keywords = "Chemical diffusion coefficient, Cyclic voltammetry, Doping, Electrochemical impedance spectroscopy, Lithium iron phosphate",

author = "Park, \{Chang Kyoo\} and Park, \{Sung Bin\} and Shin, \{Ho Chul\} and Cho, \{Won Il\} and Ho Jang",

year = "2011",

month = jan,

day = "20",

doi = "10.5012/bkcs.2011.32.1.191",

language = "English",

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journal = "Bulletin of the Korean Chemical Society",

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T1 - Li ion diffusivity and rate performance of the LiFePO4 modified by Cr doping

AU - Park, Chang Kyoo

AU - Park, Sung Bin

AU - Shin, Ho Chul

AU - Cho, Won Il

AU - Jang, Ho

PY - 2011/1/20

Y1 - 2011/1/20

N2 - This study reports the root cause of the improved rate performance of LiFePO4 after Cr doping. By measuring the chemical diffusion coefficient of lithium (DLi) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the correlation between the electrochemical performance of LiFePO4 and Li diffusion is acquired. The diffusion constants for LiFePO4/C and LiFe0.97Cr 0.03PO4/C measured from CV are 2.48 × 10 -15 and 4.02 × 10-15 cm2 s-1, respectively, indicating significant increases in diffusivity after the modification. The difference in diffusivity is also confirmed by EIS and the DLi values obtained as a function of the lithium content in the cathode. These results suggest that Cr doping facilitates Li ion diffusion during the charge-discharge cycles. The low diffusivity of the LiFePO 4/C leads to the considerable capacity decline at high discharge rates, while high diffusivity of the LiFe0.97Cr0.03PO 4/C maintains the initial capacity, even at high C-rates.

AB - This study reports the root cause of the improved rate performance of LiFePO4 after Cr doping. By measuring the chemical diffusion coefficient of lithium (DLi) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the correlation between the electrochemical performance of LiFePO4 and Li diffusion is acquired. The diffusion constants for LiFePO4/C and LiFe0.97Cr 0.03PO4/C measured from CV are 2.48 × 10 -15 and 4.02 × 10-15 cm2 s-1, respectively, indicating significant increases in diffusivity after the modification. The difference in diffusivity is also confirmed by EIS and the DLi values obtained as a function of the lithium content in the cathode. These results suggest that Cr doping facilitates Li ion diffusion during the charge-discharge cycles. The low diffusivity of the LiFePO 4/C leads to the considerable capacity decline at high discharge rates, while high diffusivity of the LiFe0.97Cr0.03PO 4/C maintains the initial capacity, even at high C-rates.

KW - Chemical diffusion coefficient

KW - Cyclic voltammetry

KW - Doping

KW - Electrochemical impedance spectroscopy

KW - Lithium iron phosphate

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DO - 10.5012/bkcs.2011.32.1.191

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