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Unusual Activation of Cation Disordering by Li/Fe Rearrangement in Triplite LiFeSO 4 F
Author(s) -
Kim Minkyu,
Kim Minkyung,
Park Heetaek,
Li Hong,
Kang Byoungwoo
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800298
Subject(s) - materials science , diffusion , ion , electrochemistry , charge (physics) , electrode , phase (matter) , connection (principal bundle) , activation energy , analytical chemistry (journal) , chemistry , thermodynamics , physics , organic chemistry , quantum mechanics , chromatography , structural engineering , engineering
Abstract It is reported that cation disordering in triplite LiFeSO 4 F can be activated by Li/Fe rearrangement that results from irreversible and nondestructive structural changes during the 1st charge/discharge cycle, especially during the charge. This rearrangement decreases the number of edge‐shared FeO 4 F 2 connection environments, compared to the pristine material. With this activation, triplite LiFeSO 4 F exhibits several unexpected electrochemical features in subsequent cycles; a decrease in open‐circuit voltage indicating the change in thermodynamic property, negligible volumetric change, enhanced Li diffusion, and facile phase transformation pathway. As a consequence, the cation‐disordered triplite LiFeSO 4 F achieves superior rate capability up to ≈66 mA h g −1 at 40 C rate (1.5 min discharge) and has excellent capacity retention for 500 cycles at 5 C charge/5 C discharge rate and for 1200 cycles at 2 C charge/2 C discharge rate. Therefore, triplite LiFeSO 4 F can be one of the most promising electrode materials for Li ion batteries.