A High-Voltage Cathode Material with Ultralong Cycle Performance for Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Vanadium-based polyanionic materials are promising for sodium-ion batteries (SIBs) due to high voltage and stability.
• Carbon covering and doping enhance performance and cycling stability in polyanionic compounds.

Purpose of the Study:

• To improve the electrochemical properties of vanadium-based polyanionic materials for SIBs.
• To investigate the effects of carbon capping and bulk-phase nitrogen doping on Na3V2(PO4)3.

Main Methods:

• Synthesis of Na3V(PO3)3N/C via carbon capping and bulk-phase nitrogen doping.
• Electrochemical testing of the modified material in SIBs, including cycling at 2 C and 10,000 cycles.
• Analysis of structural stability and volume change during cycling.

Main Results:

• The optimized Na3V(PO3)3N/C exhibits enhanced electromagnetic induction strength and structural stability.
• Exceptional cycling capability of 96.11% after 500 cycles at 2 C with a 4 V voltage platform.
• Impressive capacity retention of 70.26% after 10,000 cycles at 2 C due to quasi-zero strain property (0.12% volume change).

Conclusions:

• Carbon capping and bulk-phase nitrogen doping significantly enhance the electrochemical performance of vanadium-based phosphate materials.
• The developed Na3V(PO3)3N/C demonstrates excellent cycling stability and capacity retention for SIBs.
• A facile and cost-effective synthesis method for stable vanadium-based phosphate materials is presented.