Open-Pore Skeleton Prussian Blue as a Cathode Material to Achieve High-Performance Sodium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Prussian blue analogs (PBAs) are promising cathode materials for sodium-ion batteries (SIBs).
• Challenges include defect vacancies, high water content, and lattice instability during ion cycling, hindering performance.
• Stress accumulation during sodium ion insertion/extraction degrades electrochemical performance.

Purpose of the Study:

• To develop a high-performance and stable cathode material for SIBs.
• To address the limitations of conventional PBAs in SIB applications.
• To investigate a novel iron-based Prussian blue with an open-pore structure.

Main Methods:

• A facile template method using polyvinylpyrrolidone (PVP) and sodium citrate was employed.
• Controlled crystallization rate and particle morphology adjustment were key.
• Ex situ X-ray diffraction (XRD) was used to study the sodium ion insertion/extraction mechanism.

Main Results:

• The prepared iron-based Prussian blue (PB-3) exhibited an open-pore skeleton structure.
• PB-3 demonstrated excellent kinetic properties and mitigated volume changes during ion cycling.
• Superior rate performance (92 mAh g⁻¹ at 2000 mA g⁻¹) and cycling stability (90.2% retention after 600 cycles at 500 mA g⁻¹) were achieved.

Conclusions:

• The stabilized lattice structure of PB-3 enhances long-term cycling performance in SIBs.
• The material's considerable capacitance contributes to its excellent rate capability.
• This study offers insights for developing advanced, stable cathodes for SIBs.