Assembly of flower-like Mn3O4/NiCo-LDH@carbon nanotube nanocomposites on Ni foam for binder-free capacitor electrode

Abstract

In this work, the direct assembly of flower-like Mn3O4/NiCo-layered double hydroxide@multiwalled carbon nanotube nanocomposites on Ni foam (Mn3O4/NiCo-LDH@MWCNT/Ni foam) was achieved with a novel two-step method. MWCNTs, which were uniformly coated with NiCo-LDH and chitosan (CS), were electrodeposited on Ni foam from an acidic aqueous solution of CS, cobalt nitrate and nickel nitrate under a constant potential of − 2.0 V vs. SCE. The obtained electrode was denoted as CS/NiCo-LDH@MWCNT/Ni foam. Then, CS/NiCo-LDH@MWCNT/Ni foam was heated in potassium permanganate (KMnO4) solution. During the hydrothermal process, CS/NiCo-LDH@MWCNT/Ni foam was transformed into Mn3O4/NiCo-LDH@MWCNT/Ni foam via an in-situ redox reaction between KMnO4 and CS. Mn3O4/NiCo-LDH@MWCNT/Ni foam exhibits excellent charge storage capability as characterized by the cyclic voltammetry (CV) and galvanostastic charge/discharge (GCD) techniques. The successful applications of asymmetric supercapacitor device (ASC) assembled with Mn3O4/NiCo-LDH@MWCNT/Ni foam and activated carbon (AC) as positive and negative electrodes illustrate the great application prospect of Mn3O4/NiCo-LDH@MWCNT/Ni foam.