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Nano Research

Article Title

Bonding VSe2 ultrafine nanocrystals on graphene toward advanced lithium-sulfur batteries

Authors

Wenzhi Tian, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Baojuan Xi, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Yu Gu, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Qiang Fu, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Zhenyu Feng, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Jinkui Feng, Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan 250061, China
Shenglin Xiong, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China

Keywords

sulfiphilic VSe2, lithium–sulfur batteries, nucleation and growth of Li2S, polysulfide electrocatalysis, shuttle effect

Abstract

Lithium–sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causing rapid capacity degradation. Herein, we report the first example of sulfiphilic VSe2 ultrafine nanocrystals immobilized on nitrogen-doped graphene to modify the battery separator for alleviating the shuttling problem. VSe2 nanocrystals provide numerous active sites for chemisorption of polysulfides as well as benefit the nucleation and growth of Li2S. Furthermore, the kinetic reactions are accelerated which is confirmed by higher exchange current density and higher lithium ion diffusion coefficient. And the first-principles calculations further show that the exposed sulfiphilic planes of VSe2 boost the redox of Li2S. When used as separators within the lithium sulfur batteries, the cell indicates greatly enhanced electrochemical performances with excellent long cycling stability and exceptional rate capability up to 8 C. Moreover, it delivers a higher areal capacity of 4.04 mAh·cm−2 as well as superior cycling stability with sulfur areal loading up to 6.1 mg·cm−2. The present strategy can encourage us in engineering novel multifunctional separators for energy-storage devices.

Graphical Abstract

Publisher

Tsinghua University Press

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