A new dual-ion battery based on amorphous carbon

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-based dual-ion batteries (NDIBs) offer abundant resources, low cost, and high energy density but suffer from low capacity and poor cycling.
• Existing NDIBs typically use graphite cathodes, limiting ion accommodation to anions like PF6-.

Purpose of the Study:

• To introduce a novel amorphous carbon (AOMC) cathode material for high-performance NDIBs.
• To investigate a new ion storage mechanism in NDIBs utilizing AOMC's unique properties.
• To enhance the capacity and cycling stability of NDIBs.

Main Methods:

• Fabrication and electrochemical testing of NDIBs with AOMC cathodes.
• Ex-situ characterization using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy.
• Analysis of ion storage mechanisms and structural evolution of AOMC during cycling.

Main Results:

• AOMC demonstrates a dual-ion storage mechanism, accommodating both Na+ cations and PF6- anions.
• The amorphous structure of AOMC facilitates partial graphitic stacking upon cycling, enhancing performance.
• Achieved a high reversible capacity of 136 mAh/g over 800 cycles at 2.0 A/g, surpassing existing NDIBs.
• Demonstrated the potential for generalization to high-performance dual-ion full cells.

Conclusions:

• Amorphous carbon is a promising cathode material for developing high-performance NDIBs.
• The dual-ion storage mechanism in AOMC significantly improves capacity and cycling stability.
• This work provides a new conceptual framework for designing advanced dual-ion battery systems.