A Polymer-Infused Solid-State Synthesis of a Long Cycle-Life Na3V2(PO4)3/C Composite

The cost of large-scale battery-based energy storage systems can be substantially reduced by using long cycle-life active battery materials which can be easily synthesized. This paper describes the synthesis of a sodium vanadium phosphate (Na3V2(PO4)3, NVP)/carbon composite as the sodium ion battery (NIB) cathode material by a facile solid-state method which can increase the cost competitiveness of NIBs relative to the lithium ion batteries (LIBs). The NVP synthesized as such features NVP particles tethering to a cellular carbon network formed in situ by the carbonization of a low melting polymer percolating the NVP particles. The immobilization of the NVP particles can better preserve their electrical integration within the electrode, the loss of which is conjectured to be the major cause of capacity loss. The hypothesis was validated by performance comparison with a conventional carbon-coated NVP/C composite with the same initial discharge capacity but which showed a more severe capacity fading in extended cycling. This study presents not only a new strategy to extend the cycle life of cathode materials but also a cost-effective way to produce them.