Zeolitic imidazolate framework-7 textile-derived nanocomposite fibers as freestanding supercapacitor electrodes

Abstract

Zeolitic imidazole frameworks (ZIFs) are a class of metal organic frameworks (MOFs) with diverse energy-related applications. High-surface area materials derived from ZIFs can serve as electrodes with good long-term capacity retention. Herein, we demonstrate an electrospun ZIF7/carbon nanofiber (CNF) derived nanocomposite as a freestanding electrode for supercapacitors with excellent capacitance retention. The optimal ZIF7 composite nanofiber carbonized at 950 degrees C exhibited a specific capacitance of 202 F.g(-1) at a current density of 1 kg(-1) and similar to 98% specific capacitance retention after 5000 charge-discharge cycles. N-doped nanoporous C and the Zn framework of ZIF7 composite fibers delivered an energy density of 42 W.h.kg(-1) at a power density of 0.6 kW.kg(-1). These scalable ZIF7/CNF composite textiles (30 x 10 cm(2)) can be used as freestanding super capacitor electrodes without a separate substrate or current collector.