Zero-Waste Polyanion and Prussian Blue Composites toward Practical Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Achieving closed-loop transformations of raw materials into high-value products is crucial for societal sustainability but remains challenging.
• Current methods for producing battery materials often involve significant waste and resource consumption.

Purpose of the Study:

• To develop a low-cost, solvent-free, and "zero-waste" mechanochemical protocol for the large-scale preparation of sodium-ion battery (SIB) cathode materials.
• To investigate the synergistic effects in the synthesized composite for enhanced electrochemical performance.

Main Methods:

• A solvent-free mechanochemical grinding technique was employed for material synthesis.
• In situ characterizations and density functional theory (DFT) calculations were used to elucidate synergistic effects.
• The process was scaled up to kilogram-grade production.

Main Results:

• The mechanochemical protocol ensured full raw material utilization, reduced water consumption, and simplified operations.
• The composite cathode material, featuring cubic Prussian blue analogs (c-NFFHCF) and dehydrated polyanionic sulfates (m-NFS), demonstrated promising wide-temperature electrochemical performance.
• Synergistic effects between c-NFFHCF and m-NFS were confirmed, highlighting their contribution to performance.

Conclusions:

• The proposed mechanochemical strategy offers a sustainable and scalable approach for SIB cathode material preparation.
• This method provides a viable route for the value-added utilization of by-products from Prussian blue analog synthesis.
• The developed "zero-waste" cathode materials show significant potential for low-cost, practical SIB applications.