Membranes of carbon nanofibers with embedded MoO3 nanoparticles showing superior cycling performance for all-solid-state flexible supercapacitors

Abstract

Flexible, free-standing and binder-free membranes of carbon nanofibers with embedded α-MoO3 nanoparticles (MoO3-CNF) were fabricated by electrospinning. Benefiting from the spatial isolation of the ultrasmall α-MoO3 nanoparticles (5–10 nm) in the conductive carbon matrix, the storage of electrolytic cations in the layered structure of α-MoO3 results in a fast intercalation pseudocapacitance and a confinement of the material volume change during cycling, and consequently a high specific capacitance (544 mF cm−2 at 1 mA cm−2) and an excellent cycling stability (106.7% retention after 20,000 cycles). All-solid-state flexible supercapacitors were constructed with the MoO3-CNF membrane electrodes and KOH-PVA gel electrolyte, and good rate capability and long cycle life were achieved as well. This work provides a solution for improving the rate and cycling performance of pseudocapacitors with transition metal oxide electrodes. In addition to the superior electrochemical performance of the MoO3-CNF membrane, the preparation route, which is facile and suitable for mass production, make such kind of supercapacitors promising for the next-generation energy storage devices.