Na 3 V 2 (PO 4 ) 2 F 3 @bagasse carbon as cathode material for lithium/sodium hybrid ion battery.

The nano-scale spherical Na 3 V 2 (PO 4 ) 2 F 3 with a NASICON structure phase was prepared with a spray drying technique, and the bagasse in Guangxi, China was selected as the carbon source to prepare Na 3 V 2 (PO 4 ) 2 F 3 /C. The optimal preparation conditions of the composite determined using thermogravimetry, X-ray diffraction, scanning electron microscopy and electrochemical testing were: a calcination temperature of 650 °C and a 20% carbon source. The Na 3 V 2 (PO 4 ) 2 F 3 /C has obvious redox peaks, determined by cyclic voltammetry (CV), at 3.90 V and 3.75 V, 4.32 V and 4.15 V. These two pairs of redox peaks correspond to the escape/intercalation of the two pairs of Li + /Na + . Notably, compared with pure Na 3 V 2 (PO 4 ) 2 F 3 , the specific discharge capacity of Na 3 V 2 (PO 4 ) 2 F 3 /C-20%, which were used as a cathode material for lithium-sodium hybrid ion batteries, increased from 55 mA h g -1 to 125 mA h g -1 , which was an improvement of twofold.