Ionization-bombardment assisted deposition of MXene/SiC heterostructure for micro-supercapacitor with enhanced sodium storage

Improving the energy density of MXene micro-supercapacitors (MSCs) is still a challenge because the MXene nanosheets will easily agglomerate, leading to irreversible reduction of capacity. We present SiC/MXene heterostructure by ionization-bombardment assisted deposition synthesis. Under high voltage, C–C bond and Si-O bond are broken by electron bombardment. After arc sintering, C atom and Si atom form stable Si-C bond with lower bond energy, and then form SiC nanocrystals. Furthermore, SiC nanocrystals were patterned into mesoporous SiC nanonesh to enhance the specific surface area. The surface of SiC framework is full of charge, which makes the MXene nanosheets uniformly deposited and self-assembled to form heterostructure. SiC/MXene heterostructure has low barrier, strong bonding force and fast electron migration rate. SiC nanomesh provide a conductive network, and also serve as a framework to support the MXene film, increasing ion storage space, creating an interconnected path for the conduction of Na ions. The specific capacity of the MXene/SiC MSC is up to 97.8 mF cm−2 at a current density of 1 A cm−2. The fabrication of high-performance nanostructures leads to large-scale production and micro-energy storage devices.