J. Mater. Sci. Technol. ›› 2021, Vol. 84: 124-132.DOI: 10.1016/j.jmst.2020.11.073

• Research Article • Previous Articles     Next Articles

Dealloying-derived nanoporous deficient titanium oxide as high-performance bifunctional sulfur host-catalysis material in lithium-sulfur battery

Ning Liua, Heng Maa, Lu Wanga, Yan Zhaoa,*(), Zhumabay Bakenovb, Xin Wangc,*()   

  1. aSchool of Materials Science and Engineering, Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology, Hebei University of Technology, Tianjin 300130, China
    bInstitute of Batteries LLC, Department of Chemical and Materials Engineering, National Laboratory Astana, Nazarbayev University, 53 Kabanbay Batyr Avenue, Nur-Sultan 010000, Kazakhstan
    cSouth China Academy of Advanced Optoelectronics, International Academy of Optoelectronics at Zhaoqing, South China Normal University, Guangzhou 510006, China
  • Received:2020-09-16 Revised:2020-11-22 Accepted:2020-11-27 Published:2021-09-10 Online:2021-02-05
  • Contact: Yan Zhao,Xin Wang
  • About author:wangxin@scnu.edu.cn (X. Wang).
    * E-mail addresses: yanzhao1984@hebut.edu.cn (Y. Zhao),

Abstract:

In this work, we report a facile dealloying strategy to tailor the surface state of nanoporous TiO2 towards high-efficiency sulfur host material for lithium-sulfur (Li-S) batteries. When used as a sulfur cathode material, the oxygen-deficient TiO2-x exhibits enhanced lithium polysulfides (LiPS) adsorption and conversion kinetics that effectively tackle the shuttle effect in lithium-sulfur batteries. The excellent ability of the oxygen vacancy sites on TiO2-x surface to trap LiPS is proved by experimental observations and density functional theory (DFT) calculations. Meanwhile, it also promotes conversion kinetics of lithium polysulfides, as verified by the asymmetric cell experiment. Accordingly, compared with the S/TiO2 cathode, the oxygen-deficient S/TiO2-x electrode exhibits preeminent rate and cycling performance in lithium-sulfur batteries: it delivers an ultra-low capacity decay of 0.039 % per cycle after 1000 cycles at 1 C. Tunning the surface state of metal oxides by dealloying method offers a new facile strategy to design efficient sulfur cathode materials for lithium-sulfur batteries.

Key words: Li-S battery, Oxygen defects, TiO2-x, Dealloying, Cathode