Laser‐Induced Graphene Assisting Self‐Conversion Reaction for Sulfur‐Free Aqueous Cu‐S Battery

Abstract

In aqueous/nonaqueous metal-sulfur batteries, sulfur-based redox couple exhibits significant challenges mainly due to its low electrochemical kinetics, potential shuttle effect, and large volume change. Although massive researches have been conducted to optimize or replace metal anode and cathode composite, major challenges caused by the dependency on sulfurbased redox couple still remain. In this study, a novel redox couple of CuS/ Cu 2 S, which provides the same theoretical capacity (based on conventional S/S 2− redox couple) by changing the valence of ion charge carrier, is proposed. For achieving high reversibility, commercially viable laser-induced graphene (LIG) is fabricated and used for the first time in aqueous metalsulfur batteries. By virtue of the synergism between novel redox couple and LIG, aqueous CuS/Cu 2 S battery delivers a highly reversible capacity of 1654.9 mAh g −1 in the initial cycle and retains 91.2% with 1509.5 mAh g −1 after 328 cycles. When being cycled at 2.8 A g −1 , its reversible capacity still retains 92.1% after 410 cycles. This study provides a new choice by using a sulfur-free redox couple from screening thermodynamic parameters and analyzes the functional mechanism of LIG by density functional theory, aiming to innovate the energy storage mechanism of aqueous metal-sulfur batteries.

Research Progress on the Preparation and Applications of Laser-Induced Graphene Technology

“…Moreover, the authors concluded that the large number of defects and heteroatoms in the LIG lowered the nucleation potential barrier of Li, thus promoting stable cycling of the Li-metal anode. As a result, this approach allowed the Li-metal anode to achieve a high coulombic efficiency of 99% at 1 mA cm −2 and a high cycle life of 400 h. Yang et al [ 149 ] proposed a novel CuS/Cu 2 S aqueous solution cell. They used a composite of LIG mixed with sulfur as the cathode of this cell.…”

Synergistic dual conversion reactions assisting Pb-S electrochemistry for energy storage

“…However, the limitations of the organic electrolyte itself (e.g., low ionic conductivity, flammability, and volatility) ( 6 – 8 ), the shuttle effect of polysulfide, the lithium dendrite, and large-volume changes of the battery system in the process of discharge and charge are all urgent problems to be solved in organic Li-S batteries ( 9 – 12 ). In this case, researchers have begun to focus on high ionic conductivity, nonflammable, and chemically mild aqueous metal-sulfur batteries in recent years ( 13 – 20 ). In these studies of aqueous metal-sulfur batteries, Cu-S, Fe-S, and Zn-S systems have attracted much attention due to their high reversible capacity and excellent cycling performance in aqueous electrolyte.…”

“…In these studies of aqueous metal-sulfur batteries, Cu-S, Fe-S, and Zn-S systems have attracted much attention due to their high reversible capacity and excellent cycling performance in aqueous electrolyte. Meanwhile, optimization of the cathode material ( 14 ) and electrolyte ( 17 ) of aqueous metal-sulfur batteries is also being carried out gradually. However, no new metal-sulfur chemistry was found to undertake the energy storage task, and the exploration of new systems seems to have entered a bottleneck period.…”

Gadolinium oxide nanorods decorated Ketjen black@sulfur composites as functional catalyzing polysulfides conversion in lithium/sulfur batteries

“…To address the above‐mentioned issues, many functional carbonaceous composites (carbon nanotubes/fibers, 6,7 graphene 8 and nonmetal elements doped carbonaceous 9 ) have been designed as sulfur host materials for enhancing electron transfer and dissolved polysulfides confinement. Although these well‐designed host materials can impressively improve the electrochemical properties of sulfur cathode, the weak physical interaction between the non‐polar carbon surface and the polar polysulfides can only decrease the diffusion rate and eventually the polysulfides still migrate out of the carbon host to cause shuttle effect, which resulting in sluggish redox kinetics of the lithium polysulfides 10 …”

“…1,2 However, the poor conductivity of sulfur in LSBs, the tricky polysulfides shuttle can cause loss of active sulfur mass and corrosion of the lithium anode, and the migration of polysulfides can damage the electrode structure, further causing degradation of electrochemical performance and rapid decay of capacity. [3][4][5] To address the above-mentioned issues, many functional carbonaceous composites (carbon nanotubes/ fibers, 6,7 graphene 8 and nonmetal elements doped carbonaceous 9 ) have been designed as sulfur host materials for enhancing electron transfer and dissolved polysulfides confinement. Although these well-designed host materials can impressively improve the electrochemical properties of sulfur cathode, the weak physical interaction between the non-polar carbon surface and the polar polysulfides can only decrease the diffusion rate and eventually the polysulfides still migrate out of the carbon host to cause shuttle effect, which resulting in sluggish redox kinetics of the lithium polysulfides.…”