Unravelling the Solvation Structure and Interfacial Mechanism of Fluorinated Localized High Concentration Electrolytes in K-ion Batteries |
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Authors: | Ping Nie Meiqi Liu Wenhui Qu Meiqi Hou Limin Chang Zhuomei Wu Hairui Wang Jiangmin Jiang |
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Affiliation: | 1. Key Laboratory of Preparation and Applications of Environmental Friendly Material of the Ministry of Education & College of Chemistry, Jilin Normal University, Changchun, 130103 P. R. China;2. The Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology and Equipments, School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116 P. R. China |
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Abstract: | Electrolyte is critical for the electrochemical properties of potassium-ion batteries. The high-concentration electrolyte has achieved significant effects in inhibiting the growth of dendrites and improving the cycle life of potassium ion batteries. However, the application remains challenging owing to the issues of high viscosity, low conductivity and poor electrode wettability. Herein, a fluorinated localized high concentration electrolyte (LHCE) based on potassium bis(fluorosulfonyl) imide/dimethoxyethane is designed for use in K-ion batteries. The electrolyte structure, interfacial mechanism and diffusion kinetics are analyzed systematically through physical/electrochemical characterization and molecular dynamics simulations. The LHCE is proven to have excellent oxidation stability, low flammability, and excellent electrode wettability. Furthermore, the LHCE is investigated in a half-cell assembled by using polyimide-derived nitrogen doped carbon material as an anode, which exhibits a reversible capacity of 169 mAh g?1 and high-capacity retention upon 200 cycles at a current rate of 100 mA g?1. Fundamental mechanism on enhanced cycling stability of the carbon anodes using optimized LHCE is also investigated. This work demonstrates an example of developing new electrolytes for high performance potassium ion batteries, and also provides theoretical guidance and significant reference for electrode interphase design and engineering. |
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Keywords: | carbon anodes electrolytes interface engineering localized high concentration potassium ion batteries |
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