Tungsten Carbide as a Highly Efficient Catalyst for Polysulfide Fragmentations in Li–S Batteries

Abstract

The sluggish disproportionation of short-chain lithium polysulfides, Li 2 S x , is known to be one of the major causes to limit the rate capability of lithium−sulfur batteries. Herein, we report that tungsten carbide not only affords strong sulfiphilic surface moieties but also provides an efficient catalysis to enhance the polysulfide fragmentation, leading to a drastic improvement in the electrode kinetics. We show that tungsten carbide acts as a superb anchoring material for the long-chain polysulfide and also promotes the dissociation of short-chain polysulfide during the electroreduction process. This leads to a high-rate performance of the composite cathode loaded with tungsten carbide, delivering a markedly enhanced discharge capacity of 780 mA h g −1 at a high current rate of 5 C, when it is applied with a combination of a carbon-coated separator for the polysulfide confinement. Hence, this work presents a new strategic approach for a high-power lithium−sulfur battery.

Adsorption‐Catalysis Design in the Lithium‐Sulfur Battery

“…[62] Spired by good performance delivered by carbide with low cost, Huang and co-workers found another material (Mo 2 C) as catalyst and absorbent for LiPSs. [62] Spired by good performance delivered by carbide with low cost, Huang and co-workers found another material (Mo 2 C) as catalyst and absorbent for LiPSs.…”

“…In order to anchor LiPSs effectively, Kim et al showed that tungsten carbides (WC) can not only catalyze the disproportionation of polysulfide but also capture the soluble LiPSs. Further study indicated that WC could accelerate the reaction which is the “bottleneck” reaction of the three main reactions during the discharge process . Spired by good performance delivered by carbide with low cost, Huang and co‐workers found another material (Mo 2 C) as catalyst and absorbent for LiPSs.…”

Recent advances in chemical adsorption and catalytic conversion materials for Li–S batteries

“…Metal carbides and other metal compounds: The surface of WC is sulfiphilic, and WC could be used as effective catalyst to improve the electrode reaction kinetics by modulating the LiPS fragmentation [203] . As presented in Fig.…”

Advances in Cathode Materials for High-Performance Lithium-Sulfur Batteries

“…Copyright 2015, Wiley-VCH.(C) Schematic drawing describing the enhanced kinetics of composite electrode with WC used as additive.(D) Rate capability of the bare electrode, WC electrode, WC electrode with C-coated separator and WC electrode with C/WC-coated separator cells. Reprinted with permission from (Choi et al., 2018). Copyright 2018, American Chemical Society.…”

“…reported that tungsten carbide (WC) was used as a cathode additive to enhance the electrochemical performance (reversible capacity and rate capability) of LSBs (Choi et al., 2018). This study demonstrated that WC could offer the strong sulfiphilic surface moieties to entrap dissolved polysulfides.…”