Coordination-tuned Na₃V₂(PO₄)₃ cathodes for low-temperature sodium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Sodium-ion batteries (SIBs) are promising energy storage solutions.
• Na3V2(PO4)3 (NVP) is a potential cathode material for SIBs.
• Improving NVP's low-temperature performance and cycling stability is crucial for practical applications.

Purpose of the Study:

• To develop a synergistic doping and substitution strategy for Na3V2(PO4)3 (NVP) cathodes.
• To precisely tune the local coordination environment of NVP.
• To enhance the structural stability and electrochemical performance of NVP, particularly at low temperatures.

Main Methods:

• Synergistic doping with Nb5+ and substitution with SiO44- were employed.
• The local coordination environment of NVP was precisely tuned.
• Electrochemical performance, including cycling stability and rate capability at low temperatures, was evaluated.

Main Results:

• The optimized NVP cathode exhibited enhanced structural integrity.
• Exceptional cycling stability was achieved: 96% capacity retention after 3000 cycles at 10 A g-1 and -20 °C.
• Remarkable fast-charging capability was demonstrated: 60% state of charge in 14.1 minutes at -20 °C.

Conclusions:

• The Nb5+ doping and SiO44- substitution strategy effectively optimizes NVP structure and performance.
• This approach significantly enhances low-temperature cycling stability and fast-charging capabilities of NVP cathodes.
• The findings offer a viable pathway for developing high-performance SIBs for cold environments.