Abstract
It is reported that cation disordering in triplite LiFeSO4F 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 FeO4F2 connection environments, compared to the pristine material. With this activation, triplite LiFeSO4F 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 LiFeSO4F 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 LiFeSO4F can be one of the most promising electrode materials for Li ion batteries.
Original language | English |
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Article number | 1800298 |
Journal | Advanced Energy Materials |
Volume | 8 |
Issue number | 22 |
DOIs | |
State | Published - 6 Aug 2018 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Keywords
- activation of cation-disordering in polyanion compounds
- nondestructive structural changes by Li/Fe rearrangement
- triplite LiFeSOF