Design of ZnSe-CoSe heterostructure decorated in hollow N-doped carbon nanocage with generous adsorption and catalysis sites for the reversibly fast kinetics of polysulfide conversion

• Published in: Journal of energy chemistry 2023-11, Vol.86, p.135-145
• Main Authors: Feng, Junan, Shi, Chuan, Dong, Hanghang, Zhang, Chaoyue, Liu, Wendong, Liu, Yu, Wang, Tianyi, Zhao, Xiaoxian, Chen, Shuangqiang, Song, Jianjun
• Format: Article
• Language: English
• Subjects: Bi-directional catalysis; Conversion Kinetics; Heterostructure; Hollow structure; Lithium-sulfur batteries
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2023.07.007

The ZnSe-CoSe heterojunction with enhanced conductivity and robust adsorption-catalytic effect on polysulfide is rationally constructed and significantly improves the electrochemical performance of lithium-sulfur batteries under high S loading and low E/S. [Display omitted] Although lithium-sulfur batteries (LiSBs) are regarded as one of the most promising candidates for the next-generation energy storage system, the actual industrial application is hindered by the sluggish solid–liquid phase conversion kinetics, severe shuttle effect, and low sulfur loadings. Herein, a zeolitic imidazolate framework (ZIF) derived heterogeneous ZnSe-CoSe nanoparticles encapsulated in hollow N-doped carbon nanocage (ZnSe-CoSe-HNC) was designed by etching with tannic acid as a multifunctional electrocatalyst to boost the polysulfide conversion kinetics in LiSBs. The hollow structure in ZIF ensures large inner voids for sulfur and buffering volume expansions. Abundant exposed ZnSe-CoSe heterogeneous interfaces serve as bifunctional adsorption-catalytic centers to accelerate the conversion kinetics and alleviate the shuttle effect. Together with the highly conductive framework, the ZnSe-CoSe-HNC/S cathode exhibits a high initial reversible capacity of 1305.3 mA h g−1 at 0.2 C, high-rate capability, and reliable cycling stability under high sulfur loading and lean electrolyte (maintaining at 745 mA h g−1 after 200 cycles with a high sulfur loading of 6.4 mg cm−2 and a low electrolyte/sulfur ratio of 6 μL mg−1). Theoretical calculations have demonstrated the heterostructures of ZnSe-CoSe offer higher binding energy to lithium polysulfides than that of ZnSe or CoSe, facilitating the electron transfer to lithium polysulfides. This work provides a novel heterostructure with superior catalytic ability and hollow conductive architecture, paving the way for the practical application of functional sulfur electrodes.