All Si₃ N₄ Nanowires Membrane Based High-Performance Flexible Solid-State Asymmetric Supercapacitor.

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Growing demand for flexible and portable electronic devices necessitates advanced energy storage solutions.
• Existing flexible energy storage often compromises on energy density, weight, or durability.
• Vertically oriented graphene nanosheets (VGNs) offer potential as conductive substrates for flexible electrodes.

Purpose of the Study:

• To develop a novel flexible electrode material for high-performance energy storage devices.
• To investigate the electrochemical properties of silicon nitride nanowires (Si3N4 NWs) functionalized with VGNs and metal oxides.
• To fabricate and characterize a flexible solid-state asymmetric supercapacitor (ASC) based on these materials.

Main Methods:

• In situ fabrication of VGNs on Si3N4 NWs membrane via plasma-enhanced chemical vapor deposition (PECVD).
• Preparation of NiCo2O4 hollow nanospheres (HSs) and FeOOH amorphous nanorods (NRs) as electrode materials on Si3N4 NWs@VGNs.
• Assembly of an all Si3N4 NWs membrane-based flexible solid-state ASC using the prepared electrodes and NWs as a separator.

Main Results:

• The synthesized Si3N4 NWs@VGNs@NiCo2O4 HSs and Si3N4 NWs@VGNs@FeOOH NRs electrodes demonstrated excellent electrochemical performance.
• The assembled ASC achieved a high energy density of 96.3 Wh kg−1 with a wide operating potential window of 1.8 V.
• The flexible ASC exhibited outstanding cycling stability (91.7% after 6000 cycles) and good mechanical flexibility.

Conclusions:

• This study presents a viable strategy for designing flexible electrode materials using Si3N4 NWs and VGNs.
• The developed flexible solid-state ASC shows promising potential for next-generation portable electronic applications.
• The findings broaden the application scope of Si3N4 NWs in the field of flexible energy storage.