Chemistry - A European Journal
Chemistry - A European Journal
5 years ago

Oxygen-Deficient Titanium Dioxide Nanosheets as More Effective Polysulfide Reservoirs for Lithium-Sulfur Batteries

Oxygen-Deficient Titanium Dioxide Nanosheets as More Effective Polysulfide Reservoirs for Lithium-Sulfur Batteries
Xing-Long Wu, Yan-Ping Zheng, Ling-Na Sun, Jing-Ping Zhang, Xiao-Hua Zhang, Chao-Ying Fan, Han-Chi Wang, Hai-Zhu Sun, Si-Yu Liu, Wen-Hao Li
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. Oxygen-deficient cathode: A sulfur cathode modified with oxygen-deficient anatase TiO2 nanosheets (A-TiO2−xNSs-S cathode) performs better in lithium-sulfur batteries than the A-TiO2NSs-S cathode (see figure). Oxygen vacancies on the surface of the A-TiO2−xNSs provide robustly interactional active sites for lithium polysulfides, which efficiently relieve the shuttle effect, so the A-TiO2−xNSs-S cathode shows superior electrochemical properties to the A-TiO2NSs-S cathode.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701580

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.