Surface Oxygen Vacancy Inducing Li-Ion-Conducting Percolation Network in Composite Solid Electrolytes for All-Solid-State Lithium-Metal Batteries |
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Authors: | Heejun Yun Jinil Cho Seokgyu Ryu Seonmi Pyo Heebae Kim Jeewon Lee Byeongyun Min Yong Hyun Cho Harim Seo Jeeyoung Yoo Youn Sang Kim |
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Affiliation: | 1. Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826 Republic of Korea;2. School of Energy Engineering, Kyungpook National University, Daegu, 41566 Republic of Korea;3. Department of Chemical and Biological Engineering and Institute of Chemical Processes, College of Engineering, Seoul National University, Seoul, 08826 Republic of Korea |
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Abstract: | Composite solid electrolytes (CSEs) are newly emerging components for all-solid-state Li-metal batteries owing to their excellent processability and compatibility with the electrodes. Moreover, the ionic conductivity of the CSEs is one order of magnitude higher than the solid polymer electrolytes (SPEs) by incorporation of inorganic fillers into SPEs. However, their advancement has come to a standstill owing to unclear Li-ion conduction mechanism and pathway. Herein, the dominating effect of the oxygen vacancy (Ovac) in the inorganic filler on the ionic conductivity of CSEs is demonstrated via Li-ion-conducting percolation network model. Based on density functional theory, indium tin oxide nanoparticles (ITO NPs) are selected as inorganic filler to determine the effect of Ovac on the ionic conductivity of the CSEs. Owing to the fast Li-ion conduction through the Ovac inducing percolation network on ITO NP–polymer interface, LiFePO4/CSE/Li cells using CSEs exhibit a remarkable capacity in long-term cycling (154 mAh g?1 at 0.5C after 700 cycles). Moreover, by modifying the Ovac concentration of ITO NPs via UV-ozone oxygen-vacancy modification, the ionic conductivity dependence of the CSEs on the surface Ovac from the inorganic filler is directly verified. |
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Keywords: | all-solid-state Li-metal-batteries composite solid electrolytes density functional theory indium tin oxide oxygen vacancy percolation networks poly(ethylene oxide) |
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