Localized High‐Concentration Electrolytes Boost Potassium Storage in High‐Loading Graphite
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- Department of Chemistry and Biochemistry The Ohio State University 151 West Woodruff Avenue Columbus OH 43210 USA
- Shenzhen Key Laboratory for Graphene‐Based Materials and Engineering Laboratory for Functionalized Carbon Materials Shenzhen Geim Graphene Center Graduate School at Shenzhen Tsinghua University Shenzhen 518055 P. R. China
Abstract Reversible intercalation of potassium‐ion (K + ) into graphite makes it a promising anode material for rechargeable potassium‐ion batteries (PIBs). However, the current graphite anodes in PIBs often suffer from poor cyclic stability with low coulombic efficiency. A stable solid electrolyte interphase (SEI) is necessary for stabilizing the large interlayer expansion during K + insertion. Herein, a localized high‐concentration electrolyte (LHCE) is designed by adding a highly fluorinated ether into the concentrated potassium bis(fluorosulfonyl)imide/dimethoxyethane, which forms a durable SEI on the graphite surface and enables highly reversible K + intercalation/deintercalation without solvent cointercalation. Furthermore, this LHCE shows a high ionic conductivity (13.6 mS cm −1 ) and excellent oxidation stability up to 5.3 V (vs K + /K), which enables compatibility with high‐voltage cathodes. The kinetics study reveals that K + intercalation/deintercalation does not follow the same pathway. The potassiated graphite exhibits excellent depotassiation rate capability, while the formation of a low stage intercalation compound is the rate‐limiting step during potassiation.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- FG02-07ER46427
- OSTI ID:
- 1570486
- Journal Information:
- Advanced Energy Materials, Journal Name: Advanced Energy Materials Journal Issue: 44 Vol. 9; ISSN 1614-6832
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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