Centrifugal Spinning: An Alternative for Large Scale Production of Silicon-Carbon Composite Nanofibers for Lithium Ion Battery Anodes

摘要

Composites made of silicon nanostructures in carbon matrixes are promising materials for anodes in Li ion batteries given the synergistic storage capacity of slicon combined with the chemical stability and electrical conductivity of carbonaceous materials. This work presents the development of Si/C composite fine fiber mats produced by carbonization of pory(vinyl alcohol) (PVA)/Si composites. PVA has a high carbon content (ca. 54.5%) and, being water-soluble, it promotes the development of environmentally friendly materials. Si nanoparticles were dispersed in PVA solutions and transformed into fine fibers using a centrifugal spinning technique given its potential for large scale production. The Si/PVA fibers mats were then subjected to dehydration by exposing them to sulfuric acid Vapor. The dehydration improved the thermal and chemical stability of the PVA matrix, allowing further carbonization at 800 degrees C. The resulting Si/C composite fibers produced binder-free anodes for lithium ion batteries that delivered specific discharge and charge capacities of 952 mA h g(-1) and 862 mA g(-1), respectively, with a Columbic efficiency of 99% after 50 cycles.