Highly integrated and interconnected CNT hybrid nanofibers decorated with α-iron oxide as freestanding anodes for flexible lithium polymer batteries

Abstract

Highly integrated and interconnected carbon nanotube (CNT) hybrid nanofibers decorated with α-Fe₂O₃ (denoted hereafter as HI-CNT/Fe₂O₃ nanofibers) were first introduced for potential use as freestanding anodes in flexible lithium polymer batteries. CNTs were modified to have a carboxyl group attached. Polyacrylonitrile (PAN) was also hydrolyzed, forming sulfonated polyacrylamide. Dipole–dipole interactions and hydrogen bonding between CNTs and PAN can form Fe(acac)₃–PAN–CNT complexes, thus allowing for the formation of highly integrated CNTs in a stable jet without being aggregated during electrospinning. The discharge capacity of a freestanding HI-CNT/Fe₂O₃ nanofiber anode after 100 cycles at 100 mA g⁻¹ was 651 mA h g⁻¹. The specific capacity of a flexible full-cell combined with a LiFePO₄ cathode was maintained at 148.5 mA h g⁻¹ (cathode-based) even after bending for 10 cycles as compared with 148.9 mA h g⁻¹ before bending.