Synthesis of Triaxial LiFePO₄ Nanowire with a VGCF Core Column and a Carbon Shell through the Electrospinning Method

National Institute of Advanced Industrial Science and Technology.

The University of Tokyo.

A triaxial LiFePO₄ nanowire with a multi wall carbon nanotube (VGCF:Vapor-grown carbon fiber) core column and an outer shell of amorphous carbon was successfully synthesized through the electrospinning method. The carbon nanotube core oriented in the direction of the wire played an important role in the conduction of electrons during the charge−discharge process, whereas the outer amorphous carbon shell suppressed the oxidation of Fe²⁺. An electrode with uniformly dispersed carbon and active materials was easily fabricated via a single process by heating after the electrospinning method is applied. Messbauer spectroscopy for the nanowire showed a broadening of the line width, indicating a disordered coordination environment of the Fe ion near the surface. The electrospinning method was proven to be suitable for the fabrication of a triaxial nanostructure.