Introduced Hierarchically Ordered Porous Architecture on a Separator as an Efficient Polysulfide Trap toward High-Mass-Loading Li–S Batteries

Abstract

The severe shuttle effect and the depletion of active sulfur result in performance deterioration, presenting two formidable issues that must be overcome to achieve high-mass-loading lithium−sulfur batteries. Herein, we reported a composite separator by introducing carbon photonic crystals with a hierarchically ordered porous structure on a commercial separator. The ordered structure and interconnected hierarchical macro−meso−micropore network of the composite separator facilitate efficient trapping of polysulfides and rapid transport of lithium ions. The high ion diffusivity promotes the conversion of polysulfides enhancing sulfur utilization and mitigating the occurrence of "dead sulfur" on the surface of the separator. Impressively, under a high sulfur loading of 3 mg cm −2 , the lithium−sulfur battery with the composite separator displayed a high reversible capacity of 1582 mA h g −1 at 0.1 C and an excellent long-term cycling performance with a decay rate of as low as 0.033% per cycle over 1500 cycles at 1 C. Surprisingly, the battery represented a high reversible capacity of 935 mA h g −1 at 0.2 C even at a sulfur loading of 6.71 mg cm −2 . The design of the composite separator underscores the pivotal role of carbon architecture in improving battery performance and brings a bright prospect to enable the commercialization of high-mass-loading lithium−sulfur batteries.

Multifunctional Lithium Phytate/Carbon Nanotube Double-Layer-Modified Separators for High-Performance Lithium–Sulfur Batteries

“…The dramatically decreased contact angle indicates the enhanced wettability of the LP/CNT-modified separator toward the electrolyte, which benefits from the polar groups LP (phosphate). The enhanced wettability can reduce the interface impedance of cathode and accelerate Li ion migration across the separator. , To evaluate the Li ion conducting behavior, Li ion transference numbers ( t Li + ) were tested by the potentiostatic polarization method. A polarization potential of 10 mV was applied on Li||Li symmetrical cells with different separators, and contact resistance is established through impedance measurements conducted before and after potentiostatic polarization.…”

“…Modification of separators in LSBs has been confirmed to be an effective strategy to suppress the shuttle effect and boost sulfur utilization. Currently, high-electronic-conductivity carbon materials including graphene, graphite, carbon nanotubes, active carbon, porous carbon, and their hybrids have been widely investigated for separator modification. However, the poor polarization of carbon materials makes these separators suffer poor Li ion conductivity and limited efficiency to block soluble polysulfides.…”

Advanced Separator Materials for Enhanced Electrochemical Performance of Lithium–Sulfur Batteries: Progress and Prospects

“…It physically and chemically captures soluble LiPSs and accelerates their redox transformation to inhibit the shuttle effect. Zhang et al used silica as a template to prepare a CPC layer to be used as a separator with a porous structure and a large–medium microporous network to achieve strong adsorption and rapid conversion.…”