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Oxygen‐Deficient Titanium Dioxide Nanosheets as More Effective Polysulfide Reservoirs for Lithium‐Sulfur Batteries
Author(s) -
Wang HanChi,
Fan ChaoYing,
Zheng YanPing,
Zhang XiaoHua,
Li WenHao,
Liu SiYu,
Sun HaiZhu,
Zhang JingPing,
Sun LingNa,
Wu XingLong
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701580
Subject(s) - polysulfide , anatase , faraday efficiency , materials science , cathode , electrochemistry , lithium (medication) , oxygen , dissolution , titanium dioxide , chemical engineering , sulfur , titanium , inorganic chemistry , rutile , adsorption , oxygen evolution , electrode , electrolyte , chemistry , catalysis , photocatalysis , metallurgy , organic chemistry , medicine , engineering , endocrinology
In this work, oxygen‐deficient anatase TiO 2 nanosheets (A‐TiO 2− x NSs) are proposed as a substrate to improve the electrochemical properties of sulfur electrodes for lithium‐sulfur (Li‐S) batteries. The A‐TiO 2− x NSs are prepared by partly reducing pristine TiO 2 nanosheets (A‐TiO 2 NSs) in NaBH 4 solution. With some oxygen vacancies on the surface of the TiO 2 nanosheets, A‐TiO 2− x NSs not only promote electronic transfer, but also act as more effective polysulfide reservoirs to minimize the dissolution of lithium polysulfides (LiPSs) than the A‐TiO 2 NSs control. Hence, upon utilization as modifiers for cathodes of Li‐S batteries, the A‐TiO 2− x NSs‐modified sulfur (A‐TiO 2− x NSs‐S) cathode exhibits a higher reversible specific capacity and greater cycling performance and rate capability than the A‐TiO 2 NSs‐modified one (A‐TiO 2 NSs‐S). For example, A‐TiO 2− x NSs‐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‐TiO 2 NSs‐S. The enhanced electrochemical properties of the A‐TiO 2− x NSs‐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.