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- Title
Oxygen-Deficient Titanium Dioxide Nanosheets as More Effective Polysulfide Reservoirs for Lithium-Sulfur Batteries.
- Authors
Wang, Han‐Chi; Fan, Chao‐Ying; Zheng, Yan‐Ping; Zhang, Xiao‐Hua; Li, Wen‐Hao; Liu, Si‐Yu; Sun, Hai‐Zhu; Zhang, Jing‐Ping; Sun, Ling‐Na; Wu, Xing‐Long
- Abstract
In this work, oxygen-deficient anatase TiO2 nanosheets (A-TiO2− xNSs) are proposed as a substrate to improve the electrochemical properties of sulfur electrodes for lithium-sulfur (Li-S) batteries. The A-TiO2− xNSs are prepared by partly reducing pristine TiO2 nanosheets (A-TiO2NSs) in NaBH4 solution. With some oxygen vacancies on the surface of the TiO2 nanosheets, A-TiO2− xNSs not only promote electronic transfer, but also act as more effective polysulfide reservoirs to minimize the dissolution of lithium polysulfides (LiPSs) than the A-TiO2NSs control. Hence, upon utilization as modifiers for cathodes of Li-S batteries, the A-TiO2− xNSs-modified sulfur (A-TiO2− xNSs-S) cathode exhibits a higher reversible specific capacity and greater cycling performance and rate capability than the A-TiO2NSs-modified one (A-TiO2NSs-S). For example, A-TiO2− xNSs-S delivers an initial specific capacity of 1277.1 mAh g−1 at 0.1 C and maintains a stable Coulombic efficiency of approximately 99.2 % after the first five cycles; these values are higher than those of 997.3 mAh g−1 and around 96.7 %, respectively, for A-TiO2NSs-S. The enhanced electrochemical properties of the A-TiO2− xNSs-S cathode can be ascribed mainly to the more effective adsorption of dissolvable and diffused LiPSs by the oxygen vacancies. Therefore, utilization of the structure of oxygen vacancies in Li-S batteries demonstrates great prospects for practical application.
- Subjects
LITHIUM sulfur batteries; TITANIUM dioxide nanoparticles; POLYSULFIDES; ELECTROCHEMICAL analysis; DISSOLUTION (Chemistry)
- Publication
Chemistry - A European Journal, 2017, Vol 23, Issue 40, p9666
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.201701580