Pre-Activated Cascade Redox Enables High-Voltage Multi-Electron Anion Storage in Graphite

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Graphite cathodes are crucial for high-voltage dual-ion batteries.
• Current graphite cathodes are limited by single-electron transfer and slow anion intercalation.

Purpose of the Study:

• To overcome the limitations of conventional graphite cathodes.
• To develop a new cathode material enabling multi-electron redox pathways for enhanced energy storage.

Main Methods:

• Intercalation of iron-chloride into graphite stabilized by oxygen functional groups.
• Investigating sequential oxidation of iron and chlorine for synergistic activation.
• Analyzing anion (PF6-) intercalation facilitated by expanded interlayer spacing.

Main Results:

• A pre-activated, cascade multi-electron redox pathway was established.
• An average of 2.61 electrons per redox event was achieved, exceeding the single-electron limit.
• The novel cathode delivered 52 mAh g-1 at 5 V (vs. Na/Na+) and 3 A g-1, outperforming conventional graphite.

Conclusions:

• The developed cathode material unlocks a new direction for high-power electrochemical energy storage.
• Integrating multi-electron redox chemistry with anion storage significantly enhances battery performance.
• This approach offers a promising strategy for next-generation dual-ion batteries.