S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Material Science and Engineering (재료공학부) Journal Papers (저널논문_재료공학부)
Energy storage in composites of a redox couple host and a lithium ion host
- Kim, Sung-Wook; Nam, Kyung-Wan; Seo, Dong-Hwa; Hong, Jihyun; Kim, Hyungsub; Gwon, Hyeokjo; Kang, Kisuk
- Issue Date
- Nano Today, Vol.7 No.3, pp.168-173
- Energy storage; Li -ion batteries; Electrochemistry; Positive electrode; Composite materials
- The quest for new positive electrodes for rechargeable lithium-ion batteries has been escalating in recent years. Until now, candidates of positive electrode were limited to crystals that contain both redox-active element (usually transition-metal) and lithium ion in the open framework with few exceptions. Here, we demonstrate lithium-free compounds, a material with little activity by itself, can be activated electrochemically by addition of LiF after the first charging. This general strategy is exemplified in various lithium-free iron compounds. Reversible lithium ion extraction and reinsertion take place for Fe2+F2, Fe2+ SO4, and Fe22+P2O7, when blended with LiF in nanoscale, in which a simultaneous valence change of Fe2+/3+ occurs above 3 V. FeF2-LiF could deliver 190 mAh g(-1) (similar to 3.53 V) at 50 mA g(-1) which is even higher energy density than that crystalline LiFePO4 can offer. Various combinations of blending are possible using this approach, which can bring a new branch of material group for positive electrodes in lithium-ion batteries. (C) 2012 Elsevier Ltd. All rights reserved.
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