Defective VSe2-Graphene Heterostructures Enabling In Situ Electrocatalyst Evolution for Lithium-Sulfur Batteries.

作者：Haina Ci, Jingsheng Cai, Hao Ma, Zixiong Shi, Guang Cui, Menglei Wang, Jia-Mei Jin, Nan Wei, Chen Lu, Wen Zhao, Jingyu Sun, Zhongfan Liu · 发表于：ACS Nano · 年份：2020 · DOI：10.1021/acsnano.0c05030 · 被引用次数：174 · 研究领域：Medicine、Materials Science

Electrocatalysts remain of vital importance for the rational management of intermediate polysulfides (LiPSs) in the realm of Li-S batteries. In terms of the transition metal-based candidates, in situ evolution of electrocatalysts in the course of electrochemical process has been acknowledged; Nevertheless, consensus has not yet been reached on their real functional states as well as catalytic mechanisms. Herein, we report an all-chemical vapor deposition design of defective vanadium diselenide (VSe2)-vertical-graphene (VG) heterostructure on carbon cloth (CC) targeting high-performance sulfur host. The electrochemistry would induce the sulfurization of VSe2 to VS2 at Se vacancy sites, which propels the adsorption and conversion of LiPSs. Accordingly, the VSe2-VG@CC/S electrode harvests an excellent cycling stability at 5.0 C with a capacity decay of only 0.039% per cycle over 800 cycles, accompanied by a high areal capacity of 4.9 mAh cm-2 under an elevated sulfur loading of 9.6 mg cm-2. Theoretical simulation combined with operando characterizations reveal the key role played by the Se vacancy with respect to the electrocatalyst evolution and LiPS regulation. This work offers insight into the rational design of heterostructure sulfur hosts throughout defect engineering.