In situ hydrothermal fabrication of a MnO2@CoMoO4@Ni nanohybrid electrode and ultrahigh energy density of ASCs

Abstract

It still remains a big challenge to fabricate a high-energy-density supercapacitor (SC). Herein, an in situ hydrothermal method is developed to fabricate the high-performance MnO₂@CoMoO₄@Ni electrode, in which the high capacitance of MnO₂ and the high electrical conductivity of CoMoO₄ nanowires are fully utilized through the closely-contacted core@shell nanostructure. Amazingly, a flexible AC@Ni//MnO₂@CoMoO₄@Ni asymmetric supercapacitor (ASC) has been fabricated, which delivers an ultrahigh energy density (2.63 mW h cm⁻³) at a power density of 4 mW cm⁻³; after being charged for 10 s, the device assembled in series by two ASCs can efficiently power 15 light emitting diodes (LEDs, 5 mm-diameter red) for more than 5 minutes. Moreover, the ASC still retains 91.28% capacitance after 10 000 cycles. We hold that a hybrid nanostructure from a high-energy-density material with a high-electric-conductivity material is a promising strategy to acquire high-performance SCs.