Mesoporous 3D NiCo2O4/MWCNT nanocomposite aerogels prepared by a supercritical CO2 drying method for high performance hybrid supercapacitor electrodes

A facile sol-gel route is developed to build mesoporous 3D NiCo2O4/MWCNT nanocomposite aerogels. The crystal structure, surface morphology and electrochemical performance of the aerogel composites are investigated by X-ray diffraction (XRD), Field-emission scanning electrochemical spectroscopy (FE-SEM) and electrochemical measurements. The effects of MWCNT concentration on the capacitance performance of MWCNT/NiCo2O4 aerogels are studied. It is found that the NiCo2O4/ MWCNT nanocomposite aerogels with MWCNTs similar to 2.1 wt% reach the maximum specific capacitance of up to 1010 F g(-1) at a discharge current density of 0.1 A g(-1) with excellent cyclic stability. Further, these materials are applied for solid-state asymmetric supercapacitors and show higher areal capacitance value (471.8 mF cm(-2)) at a current density of 5 mA cm(-2) with good cycle stability and glowing red LED for 3mins. The superior electrochemical performance is due to the mesoporous structure and well-connected metal nanoparticles with MWCNT in the nanocomposite aerogels, which can provide more active sites to enhance the electrochemical performance of the device.