Tuning spatial distribution of graphene sheets composited with polyaniline nanofiber array on carbon cloth towards ultrahigh areal energy density flexible supercapacitors

Flexible supercapacitors with high areal energy density are promising energy storage devices to meet the increasing demands for wearable and portable electronic products. Herein, three kinds of flexible electrodes were fabricated electrochemically through tuning spatial distribution of graphene sheets composited with polyaniline (PANi) nanofiber array on carbon cloth, in which graphene sheets were used as the efficient growing substrate or protecting layer for the arrays and directly inserted into the arrays. It is found that the charge storage ability of all the PANi arrays could be enhanced significantly that depended greatly on the spatial distribution of graphene sheets composited with the array. The composite electrodes composing of graphene inserted PANi array on the graphene covered carbon cloth possesses the highest areal energy density among all the electrodes. More clearly, the corresponding all−solid−state supercapacitor devices can reach outstanding performances with a maximum energy density of 313 μWh cm−2 and capacitance retention of 92.7% after 5000 cycles could be achieved in the electrolyte containing Fe3+. This work is believed to provide a new thought for fabricating cost–effective and flexible electrodes with ultrahigh areal energy density, excellent flexibility and cycle stability endow for high−energy wearable/portable energy storage devices.