Enhanced Electrochemical Kinetics with Highly Dispersed Conductive and Electrocatalytic Mediators for Lithium–Sulfur Batteries. Issue 25 (13th May 2021)

• Record Type: Journal Article
• Authors: Qian, Ji; Xing, Yi; Yang, Yong; Li, Yu; Yu, Kaixin; Li, Wanlong; Zhao, Teng; Ye, Yusheng; Li, Li; Wu, Feng; Chen, Renjie
• Is Part Of: Advanced materials. Volume 33:Issue 25(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-13
• Subjects: electrocatalysis -- Li 2S 2/Li 2S deposits -- lithium polysulfides -- lithium–sulfur batteries -- molybdenum carbide; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202100810
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Lithium–sulfur (Li–S) batteries are promising energy‐storage devices because of their high theoretical energy densities. However, the practical application of Li–S batteries is still impeded by the poor cycling performance and rate capability at practical conditions. In order to improve the performance of practical Li–S batteries, a hierarchical Mo2 C nanocluster/carbon nanosheets hybrid based hollow spherical material (Mo2 C/CHS) is designed and prepared. The hollow spheres composed of stacked carbon nanosheets can facilitate the infiltration of electrolyte. The ultrasmall and highly conductive Mo2 C nanocrystals are confined in the carbon nanosheets and expose more active sites for anchoring and conversion of lithium polysulfides and increase the number of the nuclei for Li2 S2 /Li2 S precipitation. Benefitting from the synergistic effects, Mo2 C/CHS greatly promotes electrochemical kinetics in Li–S batteries with high sulfur loading (5 mg cm −2 ). Even under lean electrolyte conditions (E/S = 7 μL mgsulfur −1 ), the Li–S batteries with Mo2 C/CHS added exhibit a discharge capacity of 904 mAh g −1 at the high current rate of 0.5 C, and with 894 mAh g −1 maintained after 200 cycles. This work provides a fundamental understanding of the electrochemical processes and guides the rational design of host and additive materials for practical Li–S batteries. Abstract : A hierarchical Mo2 C nanocluster/carbon nanosheets hybrid material is prepared to improve the performance of practical Li–S batteries. The ultrasmall and highly conductive Mo2 C nanocrystals can effectively promote anchoring and conversion of lithium polysulfides and increase the number of the nuclei for Li2 S2 /Li2 S precipitation. Benefitting from the synergistic effects, the electrochemical performance of Li–S batteries is greatly improved.