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

Highly integrated and interconnected carbon nanotube (CNT) hybrid nanofibers decorated with α-Fe 2 O 3 (denoted hereafter as HI-CNT/Fe 2 O 3 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/Fe 2 O 3 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 LiFePO 4 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. Highly integrated and interconnected CNT hybrid nanofibers decorated with α-iron oxide are prepared. The formation mechanism of the unique nanostructure is investigated, and their flexible Li + ion storage properties as anode materials and the full-cell properties are studied in detail.