Construction of 3D Pomegranate-Like Na3V2(PO4)3/ conducting carbon composites for high power sodium ion batteries
Even though Na3V2(PO4)3 (NVP) is regarded as one of the next-generation cathode materials in sodium ion batteries (SIBs), the undesirable rate performance, due to the inherent low electrical conductivity, has limited its application in demanding fields such as electric vehicles. Motivated by this fact, the present study profitably exploits an in situ grown conducting carbon to obtain a pomegranate-like construction NVP@C composite, by a simple sol-gel assisted hydrothermal technique. The as-prepared NVP@C composite consists of small carbon-coated NVP particles (~200 nm) embedded in conducting carbon matrix, which is sure to offer short ion diffussion distance, percolating electron/ion conducting pathways and stable structural integrity. As a result, the pomegranate-structured NVP@C composite displays remarkable overall electrochemical performances: a high discharge capacity (110 mAhg-1 at 1C), an excellent rate capability (92 mAhg-1 even at 50C) and an impressive cycling stability (91.3% capacity retention over 2000 cycles at 10C). Such a feasible and beneficial design provides a good strategy to other materials that require both size reduction and high electronic/ionic conductivity.