SiC-induced modification of MnCo2O4 nanoneedles fabricated on Ni foam for binder-free electrodes in high-performance asymmetrical supercapacitors

• The SiC is prepared in situ on the Ni-foam by a simple DC sputtering method. • The MnCo 2 O 4 /SiC composites are synthesized in situ on the SiC/Ni-foam via hydrothermal method . • The capacitance performance of the MnCo 2 O 4 /SiC composites is better than others. • The MnCo 2 O 4 /SiC||AC asymmetrical supercapacitors (ASCs) deliver an energy density of 90.3 Wh/kg. • The ASCs also exhibit good stability with 92.1% retention after 10,000 cycles. Supercapacitors with large energy densities are required for commercial applications. Herein, the urchin-like and hexagonal MnCo 2 O 4 /SiC composite is prepared in situ on Ni foam. The urchin-like MnCo 2 O 4 /SiC consists of nanoneedle clusters with a length of about 10 μm and a diameter of 20 nm. The MnCo 2 O 4 /SiC||AC asymmetrical supercapacitor (ASCs) shows an energy density of 90.3 Wh/kg (1.73F cm −2 ) at a power density of 1.25 kW/kg together with 92.1 % retention of the specific capacitance after 10,000 cycles. The results reveal excellent properties and large commercial potential.