A heterogeneous NiCo2O4@2D-carbyne nanohybrid – a new electrode material for robust and high energy density hybrid supercapacitors

Abstract

NiCo₂O₄ nanoparticles anchored onto 2D-carbyne nanosheets is prepared to use as a new nanohybrid electrode to enhance the capacitive performance of hybrid supercapacitors. The developed heterogeneous nanohybrid takes advantage of 2D-carbyne with high electrical conductivity and NiCo₂O₄ with a short ion diffusion pathway and hence the synergy between 2D-carbyne and NiCo₂O₄ enhances the capacitive performance with a specific capacitance of around 1766.7 F g⁻¹. Furthermore, the hybrid supercapacitor device with a maximum voltage of about 1.7 V is fabricated using NiCo₂O₄@2D-carbyne and activated carbon as the positive electrode and negative electrode. The hybrid supercapacitor device exhibits a high energy density of 62 W h kg⁻¹ at a power density of 5.31 kW kg⁻¹ over 3000 cycles with a capacity retention of about 81%. This outcome provides a new approach to develop hybrid supercapacitors with superior characteristics.