TY - JOUR
T1 - Anion Redox in an Amorphous Titanium Polysulfide
AU - Shimoda, Keiji
AU - Kuratani, Kentaro
AU - Kobayashi, Shunsuke
AU - Takeuchi, Tomonari
AU - Murakami, Miwa
AU - Kuwabara, Akihide
AU - Sakaebe, Hikari
N1 - Funding Information:
This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2), funded by the New Energy and Industrial Technology Development Organization (NEDO), Japan (Project code: P16001). The authors thank Mr. Takashi Moroishi for his support in sample preparation and NMR measurements.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022
Y1 - 2022
N2 - Amorphous transition-metal polysulfides are promising positive electrode materials for next-generation rechargeable lithium-ion batteries because of their high theoretical capacities. In this study, sulfur anion redox during lithiation of amorphous TiS4 (a-TiS4) was investigated by using experimental and theoretical methods. It was found that a-TiS4 has a variety of sulfur valence states such as S2-, S-, and S-. The S2- species became the main component in the Li4TiS4 composition, indicating that sulfur is a redox-active element up to this composition. The simulated a-TiS4 structure changed gradually by lithium accommodation to form a-Li4TiS4: S-S bonds in the disulfide units and polysulfide chains were broken. Bader charge analysis suggested that the average S valency decreased drastically. Moreover, deep lithiation of a-TiS4 provided a conversion reaction to metallic Ti and Li2S, with a high practical capacity of 1000 mAh g-1 when a lower cutoff voltage was applied.
AB - Amorphous transition-metal polysulfides are promising positive electrode materials for next-generation rechargeable lithium-ion batteries because of their high theoretical capacities. In this study, sulfur anion redox during lithiation of amorphous TiS4 (a-TiS4) was investigated by using experimental and theoretical methods. It was found that a-TiS4 has a variety of sulfur valence states such as S2-, S-, and S-. The S2- species became the main component in the Li4TiS4 composition, indicating that sulfur is a redox-active element up to this composition. The simulated a-TiS4 structure changed gradually by lithium accommodation to form a-Li4TiS4: S-S bonds in the disulfide units and polysulfide chains were broken. Bader charge analysis suggested that the average S valency decreased drastically. Moreover, deep lithiation of a-TiS4 provided a conversion reaction to metallic Ti and Li2S, with a high practical capacity of 1000 mAh g-1 when a lower cutoff voltage was applied.
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U2 - 10.1021/acsami.2c07337
DO - 10.1021/acsami.2c07337
M3 - Article
AN - SCOPUS:85135237334
SN - 1944-8244
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
ER -
