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

Sodium superionic conductor (NASICON)-type phosphate Na 3 V 2 (PO 4 ) 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 Na 3 V 2 (PO 4 ) 3 material modified with dual-carbon decoration. In this material, Na 3 V 2 (PO 4 ) 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 Na 3 V 2 (PO 4 ) 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 Na 3 V 2 (PO 4 ) 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.