Fabrication of multi-walled carbon nanotubes modified Na sub(3)V sub(2)(PO sub(4)) sub(3)/C and its application to high-rate lithium-ion batteries cathode

To further improve the rate performance and cycling stability of Na sub(3)V sub(2)(PO sub(4)) sub(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 Na sub(3)V sub(2)(PO sub(4)) sub(3)/C composite is successfully synthesized via a microwave solid-state route. The influences of MWCN added on Na sub(3)V sub(2)(PO sub(4)) sub(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 super(-1) at 0.1, 0.5, 1.0, 2.0, 5.0 and 10.0 [degrees]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 super(-1) at 10.0 [degrees]C after 20 cycles. Electrochemical impedance spectroscopy profiles reveal that the charge-transfer resistance of Na sub(3)V sub(2)(PO sub(4)) sub(3)/C is remarkably reduced after MWCN were added. In all, these results suggest that MWCN should be a promising carbon supporter for Na sub(3)V sub(2)(PO sub(4)) sub(3)/C electrode.