All Si3N4 Nanowires Membrane Based High‐Performance Flexible Solid‐State Asymmetric Supercapacitor

Abstract

Recently, much attention has been drawn in the development of flexible energy storage devices due to the increasing demands for flexible/portable electronic devices with high energy density, low weight, and good flexibility. Herein, vertically oriented graphene nanosheets (VGNs) are in situ fabricated on the surface of free‐standing and flexible Si₃N₄ nanowires (NWs) membrane by plasma‐enhanced chemical vapor deposition (PECVD), which are directly used as flexible nanoscale conductive substrates. NiCo₂O₄ hollow nanospheres (HSs) and FeOOH amorphous nanorods (NRs) are finally prepared on Si₃N_4NWs@VGNs, which are served as the positive and negative electrodes, respectively. Profiting from the structural merits, the synthesized Si₃N_4NWs@VGNs@NiCo₂O_4HSs and Si₃N_4NWs@VGNs@FeOOH_NRs membrane electrodes exhibit remarkable electrochemical performance. Using Si₃N_4NWs membrane as the separator, the assembled all Si₃N_4NWs membrane‐based flexible solid‐state asymmetric supercapacitor (ASC) with a wide operating potential window of 1.8 V yields the outstanding energy density of 96.3 Wh kg⁻¹, excellent cycling performance (91.7% after 6000 cycles), and good mechanical flexibility. More importantly, this work provides a rational design strategy for the preparation of flexible electrode materials and broadens the applications of Si₃N_4NWs in the field of energy storage.