Microwave-assisted synthesis of high-performance Na₃V₂(PO₄)₃/C cathode for sodium-ion batteries

As a promising next-generation energy storage system, sodium-ion batteries (SIBs) have attracted significant research attention following the commercialization of lithium-ion batteries, despite their current pre-commercialization status. The electrochemical performance of SIBs critically depends on cathode materials, among which polyanionic compounds have shown particular promise. Sodium vanadium phosphate (Na₃V₂(PO₄)₃) with an open three-dimensional framework has emerged as a competitive cathode candidate due to its structural stability, high theoretical capacity (117.6 mAh·g⁻¹), and elevated operating voltage (3.4 V vs. Na⁺/Na). This study presents a novel synthesis strategy for carbon-coated Na₃V₂(PO₄)₃ composites, demonstrating remarkable electrochemical performance. The optimized material exhibits an initial discharge capacity of 119.2 mAh·g⁻¹ at 0.5 C rate, approaching its theoretical limit. More importantly, it maintains 96.6 % capacity retention after 100 cycles, showcasing exceptional cycling stability. The rational material design and enhanced sodium-ion diffusion kinetics achieved through carbon modification provide valuable insights for developing high-performance polyanionic cathode materials, potentially accelerating the practical implementation of SIB technology.