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Improved structure stability and performance of a LiFeSOF cathode material for lithium-ion batteries by magnesium substitution
Tavorite LiFeSO 4 F with high Li-ion conductivity has been considered a promising alternative to LiFePO 4 . However, its poor cycle stability and low electronic conductivity limit the practical application of Tavorite LiFeSO 4 F. In the present study, we employ a solvothermal method to produce magne...
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Published in: | Physical chemistry chemical physics : PCCP 2024-05, Vol.26 (18), p.13949-13954 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | |
Online Access: | Get full text |
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Summary: | Tavorite LiFeSO
4
F with high Li-ion conductivity has been considered a promising alternative to LiFePO
4
. However, its poor cycle stability and low electronic conductivity limit the practical application of Tavorite LiFeSO
4
F. In the present study, we employ a solvothermal method to produce magnesium-substitution LiMg
x
Fe
1−
x
SO
4
F (
x
= 0, 0.02, 0.04) cathode materials in which the Mg substitutes the Fe(2) sites. The first-principles calculations demonstrate that Mg-substitution could reduce the bandgap of LiFeSO
4
F and increase its electronic conductivity to 2.5 × 10
−11
S cm
−1
. Meanwhile, CI-NEB and BV calculations reveal that the diffusion energy barrier of lithium along the (100) direction after Mg substitution is lower than the pristine sample, and the electrochemical inactive Mg
2+
could improve the structure stability. The results show that the Mg-substituted LiFeSO
4
F exhibits enhanced cycle stability and rate performance compared with the pristine LiFeSO
4
F, suggesting that the use of electrochemically inactive ion substitution may be critical for the development of high-performance LiFeSO
4
F cathode materials for lithium-ion batteries.
The electrochemical inactive Mg
2+
substituted the Fe(2) site of LiFeSO
4
F. The Mg
2+
could improve the structure stability during the lithium ion de-/insertion, thus the Mg-substituted LiFeSO
4
F exhibits outstanding electrochemical cycling stability. |
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ISSN: | 1463-9076 1463-9084 |
DOI: | 10.1039/d4cp00344f |