Electrochemically primed functional redox mediator generator from the decomposition of solid state electrolyte.

Area of Science:

• Solid-state battery technology
• Materials science
• Electrochemistry

Background:

• Sulfide solid electrolytes are promising for batteries but face oxidative decomposition challenges.
• This decomposition of phosphorus and sulfur-based electrolytes hinders practical application.

Purpose of the Study:

• To demonstrate leveraging oxidative decomposition for lithium sulfide activation.
• To present a novel method for generating redox mediators in situ.

Main Methods:

• Electrochemical activation using lithium thiophosphate as a redox mediator generator.
• X-ray adsorption near-edge spectroscopy (XANES) for chemical state analysis.
• Electrochemical impedance spectroscopy (EIS) and Raman spectroscopy for performance evaluation.

Main Results:

• Lithium thiophosphate acts as an electrochemically switched-on mediator generator.
• Catalytic effect of generated redox mediators on initial lithium sulfide charging.
• Successful activation of bulk lithium sulfide at high electrode content (up to 70 wt.%).

Conclusions:

• The study overcomes limitations of pre-solvated redox mediators by decoupling activation from electrolyte content.
• This approach enables efficient lithium sulfide activation, paving the way for advanced solid-state batteries.
• Demonstrated reasonable performance under stringent testing conditions.