One-step synthesis of a sulfur-impregnated graphene cathode for lithium–sulfur batteries

Abstract

A practical route is introduced for synthesizing a sulfur-impregnated graphene composite as a promising cathode material for lithium-sulfur batteries. Sulfur particles with a size of a few microns are successfully grown in the interior spaces between randomly dispersed graphene sheets through a heterogeneous crystal growth mechanism. The proposed route not only enables the control of the particle size of active sulfur but also affords quantitative yields of composite powder in large quantities. We investigate the potential use of the sulfur-impregnated graphene composite as a cathode material owing to its advantages of confining active sulfur, preventing the dissolution of soluble polysulfides, and providing sufficient electrical conduction. A high discharge capacity of 1237 mA h g(-1) during the first cycle and a good cyclic retention of 67% after 50 cycles are attained in a voltage range of 1.8-2.6 V vs. Li/Li(+). These results emphasize the importance of tailoring cathode materials for improving the electrochemical properties of lithium-sulfur batteries. Our results provide a basis for further investigations on advanced lithium batteries.

Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries

“…An additional peak at 163.8 eV (Fig. 2f) is at the same energy for elemental sulphur supported on carbon (S 0 -C) 37 . Similar results were obtained for Li 2 S 4 /graphite ( Supplementary Fig.…”

Electrochemical Reduction Mechanism of Sulfur Particles Electrically Isolated from Carbon Cathodes of Lithium-Sulfur Cells

“…During the first cycle, the discharge capacities of 800 ∼ 1350 mAh/g (48 ∼ 81% of theoretical capacity) have been reported in previous papers. 8,[22][23][24][25] It is thought that sulfur utilization of Li-S batteries differs depending on a number of factors including chemical nature of electrolyte solution, sulfur loading, polysulfide concentration, type of carbon in cathode, and structure of cathode materials. A similar electrochemical behavior was also observed when graphite was used instead of mesoporous carbon (Fig.…”

“…[1][2][3][4][5][6][7][8][9] Despite significant progress over the past two decades, inadequate cycle life and rate capability of Li-S batteries, which have been considered to be strongly related to the insulating nature of sulfur and the high solubility of long chain polysulfides, are slowing down their practical implementation. 1,2 To address these issues, a strategy of using sulfur composites combined with a conducting agent as the active material, instead of pure sulfur, has attracted a great deal of interest, leading to the proposal of a large number of sulfur composites with carbon or conducting polymers.…”

Lithium/Sulfur Secondary Batteries: A Review

“…Graphene is a twodimensional one-atom-thick conductor with good chemical stability, mechanical strength and flexibility and high electric conductivity. Its application in sulfur composite is proved to enhance the electrochemical performance of Li/S cells [68,[80][81][82]. Chen et al further reported a hierarchical architecture S/ MWCNT nanomicrosphere with large pores and they stated the functionalized MWNT can trap polysulfides in the electrode thus achieving higher sulfur utilization and cycle retention [83].…”

“…It is subjected to an unprecedented development in Li/S batteries recent years involving numerous innovative researches around the globe. Carbon structures such as porous carbons [65][66][67], graphene [68] or graphene oxide [69], hollow carbons [70], and carbon fibers [71,72] have been applied to be nano-adsorption materials with high levels of electrical conductivity. These carbons commonly have nanosized pores inside and sulfur exists in the pores of the materials.…”