Design Principles of Quinone Redox Systems for Advanced Sulfide Solid-State Organic Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state batteries offer a solution to dissolution issues in high-capacity quinone redox systems.
• Integrating quinone redox systems with argyrodite-type Li6PS5Cl solid-state electrolytes is challenging due to reactivity.
• Developing stable and efficient solid-state organic lithium metal batteries (LMBs) is crucial for next-generation energy storage.

Purpose of the Study:

• To identify critical factors governing the electrochemical compatibility between quinone derivatives and Li6PS5Cl.
• To establish a general principle for selecting quinone derivatives for Li6PS5Cl-based solid-state organic LMBs.
• To demonstrate the performance of novel solid-state organic LMBs utilizing compatible quinone derivatives.

Main Methods:

• Screening a library of quinone derivatives as model electrode materials.
• Analyzing electrochemical compatibility based on molecular orbital energy levels (LUMO and HOMO).
• Fabricating and testing solid-state organic LMBs with selected quinone derivatives.

Main Results:

• Electrochemical compatibility is achieved when the quinone derivative's LUMO is sufficiently higher than the Li6PS5Cl's HOMO.
• The energy difference between LUMO and HOMO is critical for electrode preparation and battery performance.
• Two novel solid-state organic LMBs based on 2,5-diamino-1,4-benzoquinone and 2,3,5,6-tetraamino-1,4-benzoquinone were successfully developed and tested.

Conclusions:

• A general principle for selecting quinone derivatives compatible with Li6PS5Cl was proposed and validated.
• This work provides critical insights for designing organic electrode materials for sulfide-based solid-state batteries.
• The findings are expected to accelerate the development of high-efficiency, long-cycle-life solid-state organic batteries.