All Si<sub>3</sub>N<sub>4</sub> Nanowires Membrane Based High‐Performance Flexible Solid‐State Asymmetric Supercapacitor
Xuemin Yin, Hejun Li, Liyuan Han, Jiachen Meng, Jinhua Lu, Qiang Song
Abstract
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 Si 3 N 4 nanowires (NWs) membrane by plasma‐enhanced chemical vapor deposition (PECVD), which are directly used as flexible nanoscale conductive substrates. NiCo 2 O 4 hollow nanospheres (HSs) and FeOOH amorphous nanorods (NRs) are finally prepared on Si 3 N 4NWs @VGNs, which are served as the positive and negative electrodes, respectively. Profiting from the structural merits, the synthesized Si 3 N 4NWs @VGNs@NiCo 2 O 4HSs and Si 3 N 4NWs @VGNs@FeOOH NRs membrane electrodes exhibit remarkable electrochemical performance. Using Si 3 N 4NWs membrane as the separator, the assembled all Si 3 N 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 Si 3 N 4NWs in the field of energy storage.