An active bifunctional natural dye for stable all-solid-state organic batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Organic electrode materials offer sustainable lithium-ion battery solutions but suffer from shuttle effects.
• All-solid-state batteries (ASSBs) are promising but face compatibility issues between organic electrodes and inorganic solid electrolytes.
• Existing challenges limit areal capacity and cycling stability in organic electrode-based ASSBs.

Purpose of the Study:

• To develop a bifunctional indigo natural dye for use as both an active material and solid molecular catalyst in sulfide-based ASSBs.
• To address the chemical and mechanical incompatibility challenges between organic electrode materials and sulfide solid electrolytes.
• To demonstrate a novel strategy for enhancing the performance of organic electrode materials in practical battery applications.

Main Methods:

• Investigated the use of indigo natural dye as a bifunctional component in Li6PS5Cl sulfide-based ASSBs.
• Optimized electrode microstructures to control the reaction between indigo and the solid electrolyte.
• Characterized the synergistic redox process and electrochemical performance.

Main Results:

• Achieved a high reversible capacity of 583 mAh g⁻¹ (379 mAh g⁻¹ from Li6PS5Cl) at 0.1 C.
• Demonstrated a high areal capacity of 3.84 mAh cm⁻².
• Exhibited good cycling stability at room temperature (25°C).
• Revealed that controlled reactions between indigo and Li6PS5Cl can catalyze synergistic redox processes.

Conclusions:

• Bifunctional indigo dye effectively functions as both an active material and catalyst in sulfide-based ASSBs.
• Controlled interfacial reactions enhance performance, challenging the notion that such reactions are detrimental.
• This strategy offers a pathway to overcome key limitations of organic electrode materials for practical ASSB applications.