Enhanced Surface Interactions Enable Fast Li+ Conduction in Oxide/Polymer Composite Electrolyte |
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Authors: | Nan Wu Po‐Hsiu Chien Yumin Qian Yutao Li Henghui Xu Nicholas S Grundish Biyi Xu Haibo Jin Yan‐Yan Hu Guihua Yu John B Goodenough |
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Abstract: | Li+‐conducting oxides are considered better ceramic fillers than Li+‐insulating oxides for improving Li+ conductivity in composite polymer electrolytes owing to their ability to conduct Li+ through the ceramic oxide as well as across the oxide/polymer interface. Here we use two Li+‐insulating oxides (fluorite Gd0.1Ce0.9O1.95 and perovskite La0.8Sr0.2Ga0.8Mg0.2O2.55) with a high concentration of oxygen vacancies to demonstrate two oxide/poly(ethylene oxide) (PEO)‐based polymer composite electrolytes, each with a Li+ conductivity above 10?4 S cm?1 at 30 °C. Li solid‐state NMR results show an increase in Li+ ions (>10 %) occupying the more mobile A2 environment in the composite electrolytes. This increase in A2‐site occupancy originates from the strong interaction between the O2? of Li‐salt anion and the surface oxygen vacancies of each oxide and contributes to the more facile Li+ transport. All‐solid‐state Li‐metal cells with these composite electrolytes demonstrate a small interfacial resistance with good cycling performance at 35 °C. |
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Keywords: | all-solid-state battery composite electrolyte Li-ion conductivity Li-ion transfer mechanism solid-state NMR |
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