Fabrication of multi-walled carbon nanotubes modified Na3V2(PO4)3/C and its application to high-rate lithium-ion batteries cathode

• Multi-walled carbon nanotubes are used to modify Na3V2(PO4)3/C for lithium-ion batteries.
• The material is successfully synthesized via a microwave solid-state route.
• The obtained product shows excellent high-rate capability.

To further improve the rate performance and cycling stability of Na3V2(PO4)3/C for lithium-ion batteries cathode, multi-walled carbon nanotubes (MWCN) have been adopted to enhance the electronic conductivity of the material. Here, the MWCN modified Na3V2(PO4)3/C composite is successfully synthesized via a microwave solid-state route. The influences of MWCN added on Na3V2(PO4)3/C are studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The obtained composite shows excellent C-rate performance, delivered capacities of 146.5, 142.3, 135.2, 126.7, 114.6 and 101.8 mAhg− 1 at 0.1, 0.5, 1.0, 2.0, 5.0 and 10.0 °C in the voltage range of 2.5–4.6 V, respectively. Moreover, the capacity retention is 92.5% with the discharge capacity of 94.2 mAhg− 1 at 10.0 °C after 20 cycles. Electrochemical impedance spectroscopy profiles reveal that the charge-transfer resistance of Na3V2(PO4)3/C is remarkably reduced after MWCN were added. In all, these results suggest that MWCN should be a promising carbon supporter for Na3V2(PO4)3/C electrode.