Catalytic Interfaces‐Enriched Hybrid Hollow Spheres Sulfur Host for Advanced Li–S Batteries

Abstract

Lithium–sulfur (Li–S) batteries are considered as a promising next‐generation energy storage technology due to its high energy density over 2500 Wh kg−1 and low cost. Its development and application require to overcome several obstacles including the large volume change, the low electrical conductivity of S/Li2S, and the shuttle effect of lithium polysulfides (LIPSs). In this work, the hollow N‐doped carbon spheres (NHCS) decorated with nanosized SnS2 (NHCS‐SnS2) are synthesized and investigated to host sulfur used as the cathode for Li–S batteries. Highly conductive NHCS offer a large specific surface area and robust confinement for active material S, while SnS2 nanoparticles provide efficient chemisorption of LIPSs and promote the deposition of solid Li2S. The NHCS‐SnS2/S cathode materials deliver a high discharge capacity 1344 mAh g−1 at 0.2 C and a low capacity decay over 200 cycles at 0.5 C. The outstanding cycling stability at 0.2 C with high sulfur loading of 3.0–3.1 mg cm−2 can also be readily attained. The excellent electrochemical performance is attributed to possible triple phase catalytic effect of NHCS‐SnS2 and electrolyte, and such structure permits the full utilization of active materials from S8 to Li2S.

Significant Constraints of SnO2, SnS2, and SnS2/SnO2 Heterostructures on Mitigating Polysulfide Shuttle Effects in Lithium‐Sulfur Batteries

“…From the above research, [56,57,60] it can be noticed that the proportion of SnS 2 in the sulfur host material is more appropriate within the range of 10-25 wt%. This proportion can provide enough active sites to inhibit the shuttle effect of polysulfides without affecting the conductivity of the cathode material and the content of elemental sulfur, so that the batteries are able to provide the high energy density and cycle stability.…”

“…When cycling at current densities of 0.2, 0.5, 1 and 2 C, the discharge capacities of NHCS-SnS 2 /S are 1344, 921, 822 and 757 mAh g À 1 , respectively. [56] After activation at 0.1 C, the NHCS-SnS 2 /S electrode shows a discharge capacity of approximately 970 mAh g À 1 at 0.5 C, and can still maintain a capacity of 713 mAh g À 1 till the 200 th cycle with the 0.133 % of capacity decay per each cycle. This cathode exhibits excellent electrochemical performance for LSBs, including high capacity, cycle stability, rapid kinetic conversion of lithium polysulfide and controlled deposition of solid Li 2 S.…”

“…[54,55] Yang et al synthesized N-doped hollow carbon spheres decorated with SnS 2 and loaded with sulfur (NHCS-SnS 2 /S), which were used as cathode materials for LSBs. [56] This structured sulfur cathode as shown in Figure 9a provides a porous 3D conductive network to promote electron transport and electrolyte penetration, while N atoms in NHCS can promote the chemical adsorption of lithium polysulfides. The internal void space in NHCS is able to accommodate the volume expansion of discharge products.…”

Recent Progress in High‐Performance Lithium Sulfur Batteries: The Emerging Strategies for Advanced Separators/Electrolytes Based on Nanomaterials and Corresponding Interfaces

“…The unstable (electro) chemistry at cathode-electrolyte interface is one of the major causes that plague the commercialization of LiÀ S batteries [52,53] (Figure 4a). To proceed the discharge/charge reaction, elemental sulfur needs to be tightly attached to a host with sustainable conduction of Li + and e À , and the cathode reaction actually occurs at the host/elemental sulfur/liquid electrolyte three-phase interface.…”

Confining sulfur in intact freestanding scaffold of yolk-shell nanofibers with high sulfur content for lithium-sulfur batteries

“…Accordingly, great effort s have been devoted to developing novel strategies to address the above issues. Among these attempts, employing the composites of carbonaceous materials and polar groups as sulfur hosts were widely reported [9][10][11][12] . For example, Wang's group reported a porous freestanding S/TiO 2 -CNFs composite as a cathode [13] .…”