Sulfur-functionalized vanadium carbide MXene (VCS) as a promising anchoring material for lithium-sulfur batteries

The development of lithium-sulfur (Li-S) batteries is hindered by capacity loss due to lithium polysulfide (LIPS) dissolution into electrolyte solutions (known as the "shuttle effect"). MXenes with excellent electrical conductivity, high mechanical strength and multiple possible active two...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2019-08, Vol.21 (34), p.18559-18568
Main Authors: Wang, Yatong, Shen, Jiale, Xu, Li-Chun, Yang, Zhi, Li, Rong, Liu, Ruiping, Li, Xiuyan
Format: Article
Language:English
Subjects:
Anchoring
Decomposition
Diffusion barriers
Dynamic stability
Electrical resistivity
Lithium
Lithium sulfur batteries
MXenes
Performance enhancement
Phase transitions
Sulfur
Thermal stability
Vanadium carbide
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Summary:The development of lithium-sulfur (Li-S) batteries is hindered by capacity loss due to lithium polysulfide (LIPS) dissolution into electrolyte solutions (known as the "shuttle effect"). MXenes with excellent electrical conductivity, high mechanical strength and multiple possible active two-dimensional surface terminations are attracting much attention as anchoring materials of Li-S batteries. Here, the S-functionalized V 2 C (V 2 CS 2 ) is designed and demonstrated to have not only dynamic and thermal stability, but also metallic character. Compared with bare V 2 C and V 2 CO 2 , V 2 CS 2 exhibits a moderate adsorption effect to suppress the "shuttle effect" and can preserve the structure of LIPSs without any decomposition. Moreover, the metallic properties of V 2 CS 2 are maintained after LIPSs are adsorbed, which can promote the electrochemical activity during the charge and discharge process. The low energy barriers of Li 2 S decomposition and Li diffusion on the V 2 CS 2 surface promise the phase transformation of LIPSs and assist the electrochemical process. Based on these remarkable results, we can conclude that V 2 CS 2 is a promising anchoring material for lithium-sulfur batteries. Our work may also inspire the exploration of other MXenes and new surface functionalization methods to improve the performance of MXenes as host materials for high performance Li-S batteries. S-functionalized V 2 C (V 2 CS 2 ) was designed and the properties of it act as anchoring material for Li-S batteries' cathode were investigated by first-principles calculations. Compared with bare V 2 C and V 2 CO 2 , V 2 CS 2 is more suitable as anchoring material.
ISSN:1463-9076
1463-9084
DOI:10.1039/c9cp03419f