Thiosulfate-Mediated Polysulfide Redox for Energetic Aqueous Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Sulfur-based aqueous batteries (SABs) offer a safe, low-cost, and high-energy storage solution.
• Sluggish redox kinetics of polysulfides limit the practical performance of SABs.
• Developing strategies to accelerate polysulfide redox processes is crucial for advancing SAB technology.

Purpose of the Study:

• To investigate a novel redox regulation strategy using thiosulfate to enhance polysulfide redox kinetics in SABs.
• To elucidate the mechanism of thiosulfate-mediated ligand-chain interaction for accelerating the S⁰/S^2- redox process.
• To evaluate the electrochemical performance and energy density of thiosulfate-mediated SABs.

Main Methods:

• Electrochemical characterization of sulfur-based aqueous batteries utilizing a K₂S₂O₃ electrolyte.
• Investigation of thiosulfate-mediated ligand-chain interaction for polysulfide redox process acceleration.
• Analysis of the contribution of the thiosulfate redox pair (S₂O₃ ^2-/S₄O₆ ^2-) to battery capacity.

Main Results:

• Thiosulfate (S₂O₃ ^2-) species facilitate rapid polysulfide reduction and reversible short-chain sulfide oxidation.
• The thiosulfate redox pair contributes additional capacity at a higher potential (>0 V vs SHE).
• The developed SAB achieved a high K⁺ storage capacity (2470 mAh g_s^-1), long cycling life (>1000 cycles), and high energy density (616 Wh kg_S+Zn^-1).

Conclusions:

• Thiosulfate-mediated redox regulation effectively accelerates polysulfide kinetics in SABs.
• This strategy leads to significantly improved capacity, cycling stability, and energy density compared to existing systems.
• The findings open a new avenue for developing high-energy aqueous batteries.