Electrospinning Synthesis of Wire-Structured LiCoO2 for Electrode Materials of High-Power Li-Ion Batteries

Abstract

An application of the Li-ion batteries to advanced transportation systems essentially requires the enhancement of the rate capability; thus, the fabrication of nanostructured cathode materials with the large surface area and short Li-ion diffusion length is particularly important. In this study, an electrospinning method was adopted for the synthesis of wire-structured LiCoO2. The diameter of the as-spun fiber obtained from the precursor solution with multiwalled carbon nanotubes (vapor-grown carbon fiber, VGCF) was thinner than that of as-spun fiber obtained from the solution without VGCF. After the heat treatment, wire-structured LiCoO2 was successfully obtained regardless of the existence of dispersed VGCF in the precursor solution, although the particle size of LiCoO2 fabricated with VGCF was smaller than that of LiCoO2 fabricated without VGCF. The charge/discharge and rate-capability experiments revealed that both resulting materials show the reversible Li-ion insertion/extraction reaction. However, due to the existence of a small irreversible capacity at the initial cycles, the interfacial resistance increases, resulting in the poor cyclability and lower charge/discharge rate capability, especially for nanowire LiCoO2 fabricated with VGCF.