A Polysulfides‐Confined All‐in‐One Porous Microcapsule Lithium–Sulfur Battery Cathode

Abstract

Developing emerging materials for high energy‐density lithium–sulfur (Li–S) batteries is of great significance to suppress the shuttle effect of polysulfides and to accommodate the volumetric change of sulfur. Here, a novel porous microcapsule system containing a carbon nanotubes/tin dioxide quantum dots/S (CNTs/QDs/S) composite core and a porous shell prepared through a liquid‐driven coaxial microfluidic method as Li–S battery cathode is developed. The encapsulated CNTs in the microcapsules provide pathways for electron transport; SnO2 QDs on CNTs immobilize the polysulfides by strong adsorption, which is verified by using density functional theory calculations on binding energies. The porous shell of the microcapsule is beneficial for ion diffusion and electrolyte penetration. The void inside the microcapsule accommodates the volumetric change of sulfur. The Li–S battery based on the porous CNTs/QDs/S microcapsules displays a high capacity of 1025 mAh g−1 after 100 cycles at 0.1 C. When the sulfur loading is 2.03 mg cm−2, the battery shows a stable cycling life of 700 cycles, a Coulombic efficiency exceeding 99.9%, a recoverable rate‐performance during repeated tests, and a good temperature tolerance at both −5 and 45 °C, which indicates a potential for applications at different conditions.

Realizing fast polysulfides conversion within yolk-shelled NiO@HCSs nanoreactor as cathode host for high-performance lithium-sulfur batteries

“…In addition, the Li–O and Ni–S bond accumulated charge density of the differential charge density indicate the promoted conversion of lithium polysulfide. 53 The calculation results are in tune with the LiPS adsorption experiment, which additionally exhibits the stronger LiPS anchoring ability of YS NiO@HCSs.…”

A graphene oxide scaffold-encapsulated microcapsule for polysulfide-immobilized long life lithium–sulfur batteries

“…48 In i = k 1 v + k 2 v 1/2 , the k 1 v and k 2 v 1/2 represent the surface capacitive contribution and diffusion contribution, respectively. 49 The results are summarized in Fig. 4c, g, and k.…”

Advances in Microfluidic Technologies for Energy Storage and Release Systems

“…At the outlet, the inner phase will be wrapped by the outer phase which formed the microcapsules continuously under the shear action of the driving fluids. [ 113 ] The same concept of coaxial droplet microfluidics has been applied to fabricate metal–organic framework‐derived nanocage microcapsules [ 114 ] and polysulfide‐confined all‐in‐one porous microcapsules ( Figure a) [ 115 ] for lithium–sulfur battery cathodes, with the latter achieving a high capacity of 1025 mAh g −1 and stable cycling life of 700 cycles. [ 115 ] Moving to sodium‐ion batteries, Zheng et al proposed a microfluidic reactor method of fabricating sodium vanadium fluorophosphate (Na 3 V 2 O 2 (PO 4 ) 2 F) for sodium‐ion battery cathodes (Figure 7b).…”

“…[ 113 ] The same concept of coaxial droplet microfluidics has been applied to fabricate metal–organic framework‐derived nanocage microcapsules [ 114 ] and polysulfide‐confined all‐in‐one porous microcapsules ( Figure a) [ 115 ] for lithium–sulfur battery cathodes, with the latter achieving a high capacity of 1025 mAh g −1 and stable cycling life of 700 cycles. [ 115 ] Moving to sodium‐ion batteries, Zheng et al proposed a microfluidic reactor method of fabricating sodium vanadium fluorophosphate (Na 3 V 2 O 2 (PO 4 ) 2 F) for sodium‐ion battery cathodes (Figure 7b). Conventional ways to fabricate Na 3 V 2 O 2 (PO 4 ) 2 F requires an extremely high temperature of up to 600 °C and long processing of 1 h. [ 116 ] However, with the proposed microfluidic technique, the whole fabrication process can be completed in just 6.3 s at a low heating temperature of 240 °C, clearly showing the superiority of this unprecedented, rapid, and controllable microfluidic fabrication strategy.…”

“…Reproduced with permission. [ 115 ] Copyright 2021, Wiley‐VCH GmbH. b) A microfluidic reactor method of fabricating sodium vanadium fluorophosphate for sodium‐ion battery cathodes which require significantly shorter fabrication time when compared to traditional methods.…”