High Capacity Li2S–Li2O–LiI Positive Electrodes with Nanoscale Ion-Conduction Pathways for All-Solid-State Li/S Batteries |
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Authors: | Yushi Fujita Atsushi Sakuda Yuki Hasegawa Minako Deguchi Kota Motohashi Ding Jiong Hirofumi Tsukasaki Shigeo Mori Masahiro Tatsumisago Akitoshi Hayashi |
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Affiliation: | 1. Department of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 Japan;2. Department of Materials Science, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 Japan |
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Abstract: | All-solid-state lithium–sulfur (Li/S) batteries are promising next-generation energy-storage devices owing to their high capacities and long cycle lives. The Li2S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li2S, solid electrolytes, and conductive carbon can be used to fabricate high-energy-density batteries. Moreover, the active material should be constructed with both micro- and nanoscale ion-conduction pathways to ensure high power. Herein, a Li2S–Li2O–LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li2S–Li2O–LiI exhibits high charge–discharge capacities and a high specific capacity of 998 mAh g?1 at a 2 C rate and 25 °C. X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy observation suggest that Li2O–LiI provides nanoscale ion-conduction pathways during cycling that activate Li2S and deliver large capacities; it also exhibits an appropriate onset oxidation voltage for high capacity. Furthermore, a cell with a high areal capacity of 10.6 mAh cm–2 is demonstrated to successfully operate at 25 °C using a Li2S–Li2O–LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries. |
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Keywords: | active materials all-solid-state lithium sulfide lithium–sulfur batteries solid electrolytes |
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