Dual-Carbon-Decorated Na3V2(PO4)3 Material for Sodium-Ion Batteries

Sodium superionic conductor (NASICON)-type phosphate Na3V2(PO4)(3) has been actively explored as a prospective cathode material for sodium-ion batteries, which serve as a cost-effective alternative to the current lithium-ion batteries. However, the electrochemical sodium storage performance of phosphates is far from expectation due to the intrinsic limitation in electron conduction. Herein, we design and fabricate Na3V2(PO4)(3) material modified with dual-carbon decoration. In this material, Na3V2(PO4)(3) particles coated with amorphous carbon are further integrated into carbon nanofibers, resulting in a dual-carbon-decorated heterostructure. As dual-carbon decoration offers an avenue for electron transport, this Na3V2(PO4)(3) cathode material exhibits an initial capacity of 109.7 mA h g(-1) and retains 73.2 mA h g(-1) at a high rate of 20 C after 1000 cycles, demonstrating robust performance for sodium storage. In situ galvanostatic intermittent titration and electrochemical impedance spectroscopy measurements reveal a significant improvement in the electronic and ionic conductivity of the dual-carbon-decorated Na3V2(PO4)(3), which contributes to superior performance of the cathode material. In general, this work provides a simple but promising solution to phosphate materials for high-performance sodium-ion batteries.