3D Holey Graphene/Polyacrylonitrile Sulfur Composite Architecture for High Loading Lithium Sulfur Batteries

Abstract

Lithium sulfur (Li–S) batteries have attracted considerable interest as next‐generation high‐density energy storage devices. However, their practical application is limited by low capacity and rapid capacity fading at commerical‐level mass loadings, which is largely attributed to the inferior electron/ion conduction, as well as severe the shuttling effect of soluble polysulfide species. To address these issues, a three‐dimensional holey graphene/polyacrylonitrile sulfur (3DHG/PS) composite cathode is developed for high‐mass‐loading Li–S batteries. The unique architectural design with the 3D holey graphene framework ensures fast electron and ion transport within the thick electrode, and affords enough space for mitigating the volume expansion of the electrode. Moreover, in situ Raman results demonstrate that covalent sulfur within 3DHG/PS fundamentally avoids forming soluble lithium polysulfides, which effectively reduces the undesired shuttling effect. With these advantages, the 3DHG/PS cathode exhibits an ultra‐low capacity fading rate of 0.012% per cycle after continuous 1500 cycles, as well as high specific capacity and superior rate capability with a high mass loading of 15.2 mg cm–2, which offers a promising avenue to construct future Li–S batteries with superior performance at mass loadings that exceed commercial levels.

In Situ/Operando Raman Techniques in Lithium–Sulfur Batteries

“…[ 62 ] Wang et al synthesized graphene/polyacrylonitrile sulfur composite as cathodes (3DHG/PS) for Li–S batteries and explored the reason why such cathode reduced the shuttle effect by in situ Raman measurements ( Figure a). [ 63 ] According to the Raman spectra, no peak assigning to long‐chain LiPSs appears during the whole operating processes of the battery using 3DHG/PS (Figure 6b–e), implying that the formation of soluble LiPSs is avoided. Huang et al designed sulfurized polyacrylonitrile (S‐cPAN) as the active material and investigated the reaction mechanism by in situ Raman combined with in situ XAS and DFT.…”

“…Reproduced with permission. [ 69 ] Copyright 2020, American Chemical Society. In situ Raman spectra and potential dependence of Raman peak intensities of Li–S battery d–f) with and g–i) without CIS.…”

Uniformly Controlled Treble Boundary Using Enriched Adsorption Sites and Accelerated Catalyst Cathode for Robust Lithium–Sulfur Batteries

“…[ 1 ] Rechargeable lithium–sulfur batteries (LSBs) are among the best candidates for next‐generation energy storage devices owing to their outstanding theoretical energy density (2600 Wh kg −1 ), high theoretical specific capacity (1675 mAh g −1 ), abundant material with low cost, and environmentally friendly process. [ 2,3 ] However, LSBs are impeded from commercialization due to insulating issues of final charge and discharge products (S and Li 2 S 2 /Li 2 S) and the dissolution of intermediate LiPS species in the electrolyte which make shuttle effect of polysulfides (LiPSs). [ 4,5 ] These barriers lead to reduced sulfur utilization, decreased Coulombic efficiency, and rapid degradation of cell capacity.…”

Multiscale Understanding of Covalently Fixed Sulfur–Polyacrylonitrile Composite as Advanced Cathode for Metal–Sulfur Batteries

“…The sulfur was covalently adopted as short chains of elemental sulfur (C—S structure) in the PAN matrix, while the long chains containing lithium PSs (Li 2 S n = 2….8 ) [ 92 , 93 ] were soluble in the electrolyte, thereby resulting in the shuttling effect leading to fatal capacity fading. [ 94 ]…”

“…Additionally, oxidized form of graphene (GO) might be able to minimize the polysulfides’ dissolution and their shuttle. [ 94 ] Furthermore, the use of graphene in sulfur composite preparation could confirm the maximum utilization of sulfur moiety. [ 113 ] A sulfur/dehydrogenated polyacrylonitrile (S/DPAN) composite was dispersed on rGO via self‐assembly in the presence of cetyltrimethylammonium bromide under simple sonication treatment, and the final product is denoted as S/DPAN/rGO.…”