Three-Dimensional Sulfur/Graphene Multifunctional Hybrid Sponges for Lithium-Sulfur Batteries with Large Areal Mass Loading

Abstract

In this communication, we introduce the concept of three dimensional (3D) battery electrodes to enhance the capacity per footprint area for lithium-sulfur battery. In such a battery, 3D electrode of sulfur embedded into porous graphene sponges (S-GS) was directly used as the cathode with large areal mass loading of sulfur (12 mg cm−2), approximately 6–12 times larger than that of most reports. The graphene sponges (GS) worked as a framework that can provide high electronic conductive network, abilities to absorb the polysulfides intermediate, and meanwhile mechanical support to accommodate the volume changes during charge and discharge. As a result, the S-GS electrode with 80 wt.% sulfur can deliver an extremely high areal specific capacitance of 6.0 mAh cm−2 of the 11th cycle, and maintain 4.2 mAh cm−2 after 300 charge−discharge cycles at a rate of 0.1C, representing an extremely low decay rate (0.08% per cycle after 300 cycles), which could be the highest areal specific capacity with comparable cycle stability among the rechargeable Li/S batteries reported ever.

Sulfur–Graphene Nanostructured Cathodes via Ball-Milling for High-Performance Lithium–Sulfur Batteries

“…Thus, the ball-milling technique effectively combines both the physical and chemical routes into one-step process for low-cost, scalable, and eco-friendly production of highly-efficient LSB 11,25,28,37 attributable to its 3D porous 'sandwich-like' structure (vide infra), coupled with the newlydiscovered 'spin-effect' induced by S-doping, leading to enhanced ionic conductivity and lithium insertion/extraction during the discharge-charge process.…”

“…To overcome the above-mentioned obstacles, carbon based materials with various hierarchical structures, including meso-/micro-porous carbons [6][7][8][9][10][11] , hollow carbon spheres [12][13][14] , carbon nanotubes/nanofibers [15][16][17][18][19] , graphene derivatives [20][21][22][23][24][25][26][27][28][29][30] , and flexible carbon membranes 31 6 C with a low decay rate of 0.039% per cycle over 1500 cycles) 25 , a sulfur-graphene composite with ~ 63.6 wt% sulfur uniformly coated on graphene through reduction of GO and concomitant sulfurization (440 mAh g -1 after 500 cycles at 0.75 C) 22 , and polyvinylpyrrolidone (PVP)-encapsulated hollow S nanospheres (i.e., S@PVP nanospheres) from the reaction of Na2S2O3 and…”

High Mass-Loading of Sulfur-Based Cathode Composites and Polysulfides Stabilization for Rechargeable Lithium/Sulfur Batteries

“…Sulfur/micro-mesoporous carbon (MC)/Teflon (PTFE)/CNT free-standing sheets (80 µm thick) offer 2.3 mAh/cm 2 , and the preparation process of the sheets (roll-press) is suitable for mass production (Thieme et al, 2013); however, the free-standing cathode sheet was laminated onto a carbon-coated expanded aluminum current collector in order to reduce contact resistance. Lu et al (2014) reported that sulfur/graphene oxide (GO) sponges can offer a 12 mg/cm 2 of mass-loading and a 4.5 mAh/cm 2 or higher capacity at 0.1 C up to 300 cycles; however, the preparation method of the sponge (hydrothermal reduction of GO hydrogel in an autoclave) is problematic for the mass production of electrodes.…”

Application of GO in Energy Conversion and Storage

“…RGO-based sulfur cathode has also received intense attentions since it possesses comparable advantages with GO while prevailed by better electronic conductivity [111][112][113][114]. The S@RGO composites with a unique saccule-like structure can provide buffer space to accommodate stress and volumetric expansion of sulfur during the charge-discharge process, which displays a discharge capacity of 724.5 mAh g −1 (sulfur mass only) at a current rate of 1 C (1 C = 1675 mA g −1 ) between 1.2 and 3.0 V [111].…”