Lithium–sulfur batteries are one of the most promising alternatives for advanced battery systems due to the merits of extraordinary theoretical specific energy density, abundant resources, environmental friendliness, and high safety. However, the sluggish sulfur reduction reaction (SRR) kinetics results in poor sulfur utilization, which seriously hampers the electrochemical performance of Li–S batteries. It is critical to reveal the underlying reaction mechanisms and accelerate the SRR kinetics. Herein, the critical issues of SRR in Li–S batteries are reviewed. The conversion mechanisms and reaction pathways of sulfur reduction are initially introduced to give an overview of the SRR. Subsequently, recent advances in catalyst materials that can accelerate the SRR kinetics are summarized in detail, including carbon, metal compounds, metals, and single atoms. Besides, various characterization approaches for SRR are discussed, which can be divided into three categories: electrochemical measurements, spectroscopic techniques, and theoretical calculations. Finally, the conclusion and outlook part gives a summary and proposes several key points for future investigations on the mechanisms of the SRR and catalyst activities. This review can provide cutting‐edge insights into the SRR in Li–S batteries.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aenm.202202094

Sulfur Reduction Reaction in Lithium–Sulfur Batteries: Mechanisms, Catalysts, and Characterization

3D ordered macroporous Pt/ZnS@ZnO core-shell heterostructure for highly effective photocatalytic hydrogen evolution

The lithium polysulfides (LiPS) dissolution into electrolyte as well as consequent shuttle behavior seriously exacerbate the electrochemical performance of lithium–sulfur batteries. Herein, the intrinsic defect of graphene has been tailored by using plasma irradiation. The topological defective carbon structure is demystified into monovacancy and divacancy which effectively promote Li–S redox kinetics by selectively decelerating the generation of soluble high-order LiPSs and passingly promoting the conversion to final solid products. Theoretical prediction uncovers the selective manipulation of Li–S redox kinetics by defective graphene, facilitating the reduced overpotential effect and uniform deposition of Li2S. Moreover, the divacancy presents a higher activity for Li–S chemistry in contrast with monovacancy. Therefore, the battery achieves superior cyclability with a capacity retention of 88.6% at 1.0 C over 300 cycles. Furthermore, it yields an areal capacity up to 8.5 mAh cm−2 with a sulfur loading of 13.3 mg cm−2. 

Deciphering the defect
 micro‐environment
 of graphene for highly efficient Li–S redox reactions

Facilitating Catalytic Activity of Indium Oxide in Lithium-Sulfur Batteries by Controlling Oxygen Vacancies

Lithium-sulfur (Li-S) batteries are promising candidates for next-generation energy storage systems owing to their high energy density and low cost. However, critical challenges including severe shuttling of lithium polysulfides (LiPSs) and sluggish redox kinetics limit the practical application of Li-S batteries. Carbon nitrides (CxNy), represented by graphitic carbon nitride (g-C3N4), provide new opportunities for overcoming these challenges. With a graphene-like structure and high pyridinic-N content, g-C3N4 can effectively immobilize LiPSs and enhance the redox kinetics of S species. In addition, its structure and properties including electronic conductivity and catalytic activity can be regulated by simple methods that facilitate its application in Li-S batteries. Here, the recent progress of applying CxNy-based materials including the optimized g-C3N4, g-C3N4-based composites, and other novel CxNy materials is systematically reviewed in Li-S batteries, with a focus on the structure-activity relationship. The limitations of existing CxNy-based materials are identified, and the perspectives on the rational design of advanced CxNy-based materials are provided for high-performance Li-S batteries. 

https://link.springer.com/content/pdf/10.1007/s40820-022-00954-x.pdf

Carbon-Nitride-Based Materials for Advanced Lithium–Sulfur Batteries

Nitrogen-doped carbon embedded with Ag nanoparticles for bidirectionally-promoted polysulfide redox electrochemistry

Ordered macroporous V-doped ZnO framework impregnated with microporous carbon nanocages as multifunctional sulfur reservoir in lithium-sulfur batteries

Altmishov Bobur Sunnatbekovich

Papers

Nitrogen-doped carbon embedded with Ag nanoparticles for bidirectionally-promoted polysulfide redox electrochemistry

Ordered macroporous V-doped ZnO framework impregnated with microporous carbon nanocages as multifunctional sulfur reservoir in lithium-sulfur batteries

Nitrogen-doped carbon embedded with Ag nanoparticles for bidirectionally-promoted polysulfide redox electrochemistry