Lychee-like TiO 2 @TiN dual-function composite material for lithium-sulfur batteries

• Published in: RSC advances 2020-01, Vol.10 (5), p.2670-2676
• Main Authors: Xu, Wei, Pang, Huimei, Zhou, Heliang, Jian, Zhixu, Hu, Riming, Xing, Yalan, Zhang, Shichao
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra09534a

Lithium-sulfur (Li-S) batteries are promising candidates for next generation rechargeable batteries because of their high energy density of 2600 W h kg . However, the insulating nature of sulfur and Li S, the "shuttle effect" of lithium polysulfides (LiPSs), and the volumetric change of sulfur electrodes limit the practical application of Li-S batteries. Here, lychee-like TiO @TiN hollow spheres (LTTHS) have been developed that combine the advantages of high adsorption TiO and high conductivity TiN to achieve smooth adsorption/spread/conversion of LiPSs and use them as a sulfur host material in Li-S batteries for the first time. The cathode exhibits an initial specific capacity of 1254 mA h g and a reversible capacity of 533 mA h g after 500 cycles at 0.2C, which corresponds to an average coulombic efficiency up to 99%. The cell with the LTTHS@S cathode achieved an extended lifespan of over 1000 cycles. Such good performance can be assigned to the good adsorption and catalysis of the dual-function TiO @TiN composite. This work proved that the TiO @TiN composite can be an attractive matrix for sulfur cathodes.