Effects of nickel-doping on the microstructure and electrochemical performances of electrospun Li3V2(PO4)3/C fiber membrane cathode

Metal ion-doping and fibrosis treatment are important ways to improve the conductivity of lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 ) electrode materials. However, the traditional casting preparation method could reduce the electronic and ionic conductivities of Li 3 V 2 (PO 4 ) 3 electrodes. In this work, the nickel (Ni)-doped Li 3 V 2 (PO 4 ) 3 /C nanofiber membrane with a three-dimensional network structure was prepared by an electrospinning technique, which was directly used for self-standing cathodes in lithium-ion batteries. The effects of Ni-doping on the morphology, structure, and electrochemical properties of Li 3 V 2 (PO 4 ) 3 /C nanofiber membrane were studied. The results show that the Ni-doping not only changes the crystal structure and morphology of Li 3 V 2 (PO 4 ) 3 /C fibers, but also affects the electrochemical performances of the Li 3 V 2 (PO 4 ) 3 /C electrodes. 1‰ Ni-doping has slightest effect on the crystal structure compared with other ratios, and the catalytic effect of Ni nanoparticles makes Li 3 V 2 (PO 4 ) 3 /C grow directionally to form a hybrid membrane containing Li 3 V 2 (PO 4 ) 3 /C nanofibers and Li 3 V 2 (PO 4 ) 3 /C nanowires. The hybrid membrane electrode possesses good electrochemical performances at the current densities of 1C and 5C owing to the long-range continuous electron conductive networks, high porosity to favor the electrolyte permeation and Li-ion transport, and stable integrated-electrode structure to enhance the redox reaction. This self-standing Li 3 V 2 (PO 4 ) 3 /C nanofiber membrane cathode is expected to be used in high-energy lithium-ion batteries.