Self-limiting lithiation of vanadium diboride nanosheets as ultra-stable mediators towards high-sulfur loading and long-cycle lithium sulfur batteries

• Published in: Sustainable energy & fuels 2021-06, Vol.5 (12), p.3134-3142
• Main Authors: Zhao, Yuwei, Yin, Hao, Zhang, Zhe, Lyu, Chongguang, Zhao, Xuan, Xu, Huakai, Lu, Gang, Qin, Tianshi, Ouyang, Gang, Zha, Chenyang, Wang, Lin
• Format: Article
• Language: English
• Subjects: Boron; Constraining; Density functional theory; Electrochemistry; Ion transport; Lithium; Lithium sulfur batteries; Nanosheets; Reaction kinetics; Sulfur; Vanadium
• ISSN: 2398-4902; 2398-4902
• DOI: 10.1039/d1se00466b

The high performance of lithium-sulfur (Li-S) batteries generally suffers from the sluggish reaction kinetics and notorious shuttle effect, resulting from the multi-phase/interface evolution and multistep electron-transfer/non-transfer processes. In this article, the novel vanadium diboride (VB 2 ) nanosheet shows the self-limiting lithiation property in the 1.5-2.8 V polysulfide reaction range, which can afford better electron/ion transport under the stable reaction interface of the catalytic mediator in the Li-S cell cycling. Moreover, electrochemical measurements and density-functional theory calculations reveal that the boron sites of VB 2 have a strong surface interaction with Li 2 S 4 , which can further improve the conversion rate between Li 2 S 4 and Li 2 S 2 /Li 2 S. Thereinto, these VB 2 -based Li-S cells possess high sulfur loading (4 mg cm −2 ), impressive current rate (2C), excellent cycling stability (1000 cycles), and great rate capability (1013 mA h g −1 at 5 mA cm −2 ). This work provides insight into the stable structure to support the advancement of electrocatalysis technology. This work on the "interface is the device" strategy provides insight into interfacial engineering to support the advancement of lithium-sulfur batteries.