Co-W bimetallic carbides as sulfur host for high-performance lithium–sulfur batteries

Abstract

Due to the low conductivity of sulfur and the dissolution of polysul des, the research and application of lithium-sulfur (Li-S) batteries have encountered certain resistance. Increasing conductivity and introducing polarity into the sulfur host can effectively overcome these long-standing problems. Herein, We rst prepared Co 3 W 3 C@ C@ CNTs / S material and used it in the cathode of lithium-sulfur batteries,The existence of carboxylated CNTs can form a conductive network, accelerate the transmission of electrons and improve the rate performance, and polar Co 3 W 3 C can form a strong interaction with polysul de intermediates, effectively inhibiting its shuttle effect, improving the utilization of sulfur cathode electrodes, and improving the capacity and cycle stability. The Co 3 W 3 C@C@CNTs / S electrode material has a capacity of 1,093 mA h g-1 at a 0.1 A g − 1 and 482 mA h g-1 at 5 A g − 1 . Even after 500 cycles of 2 A g − 1 , the capacity of each cycle is only reduced by 0.08%. The excellent stability of this material can provide a new idea for the future development of lithium-sulfur batteries.

Dual‐Functional Hosts for Polysulfides Conversion and Lithium Plating/Stripping towards Lithium‐Sulfur Full Cells

“…The design and engineering of sulfur hosts anchoring polysulfides have been proven to be a feasible approach to improve the performances of sulfur cathodes. In comparisons with non‐polar carbon‐based hosts, polar hosts are regarded as chemical‐type materials to retard the shuttling of polysulfides because of their stronger chemical binding with polysulfides and superior adsorption ability [27,29] . Besides, their catalytic behaviors in the conversion reaction between S/Li 2 S and Li 2 S n (2≤n≤8), [30] could significantly decrease the polysulfides accumulation and inhibit the polysulfides shuttle.…”

“…In comparisons with non-polar carbon-based hosts, polar hosts are regarded as chemical-type materials to retard the shuttling of polysulfides because of their stronger chemical binding with polysulfides and superior adsorption ability. [27,29] Besides, their catalytic behaviors in the conversion reaction between S/Li 2 S and Li 2 S n (2 � n � 8), [30] could significantly decrease the polysulfides accumulation and inhibit the polysulfides shuttle. Moreover, the sulfur hosts are also responded to promote the conversion kinetics by facilitating the electron transfer on their surface, which could enhance the electrical conductivity of the S cathode (Figure 2).…”