A bifunctional VS2–Ti3C2 heterostructure electrocatalyst for boosting polysulfide redox in high performance lithium–sulfur batteries. Issue 36 (31st August 2022)

• Record Type: Journal Article
• Authors: Wang, Yueyue; Xiong, Yuting; Huang, Qingyi; Bi, Zixuan; Zhang, Zexian; Guo, Zhenzhen; Wang, Xianbao; Mei, Tao
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 36(2022)
• Page Start: 18866
• Page End: 18876
• Publication Date: 2022-08-31
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta05604f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A bifunctional VS2 –Ti3 C2 heterostructure electrocatalyst is designed and applied in LSBs, combining suitable adsorption capacity, enhanced catalytic activity, and open channels to achieve a balanced and efficient "capture-diffusion-catalysis" process. Abstract : The commercial development of lithium–sulfur batteries (LSBs) is extremely hindered due to the shortcomings of sluggish reaction kinetics and the lithium polysulfide (LiPS) shuttling effect. For overcoming these limitations, a bifunctional VS2 –Ti3 C2 heterostructure electrocatalyst is designed as a sulfur host material in LSBs, combining suitable adsorption capacity, enhanced catalytic activity, and layer-by-layer interstitial channels to achieve a balanced and efficient "capture-diffusion-catalysis" process. Density functional theory (DFT) calculations indicate that the intrinsically conductive VS2 –Ti3 C2 possesses an elevated d-band center, improving interaction with LiPSs and accelerating interfacial electron transfer. In addition, the layer interstitial spaces of the 3D lamellar interspersed network facilitate lithium ion diffusion. As a result, LSBs assembled with VS2 –Ti3 C2 /S exhibit a high reversible discharge capacity (1237 mA h g −1 at 0.2C), excellent rate performance (559 mA h g −1 at 10C), and robust cycle stability (0.024% decay rate after 500 cycles at 1C). Moreover, even at a high sulfur loading of 4.0 mg cm −2, a favorable capacity of 852 mA h g −1 with a capacity retention of 90.5% is still maintained after 150 cycles. This work provides inspiring insights into heterostructure materials with a high rate and sulfur loading in mediating conversions and migrations of matter toward LSBs with promising performance.