Preparation of partially-cladding NiCo-LDH/Mn3O4 composite by electrodeposition route and its excellent supercapacitor performance

A NiCo-LDH/Mn3O4 composite is synthesized on nickel foam substrate though a two-step electrodepositon process. The growth of Mn3O4 nanoneedles on NiCo-LDH nanosheets can greatly reduce the transport pathway of electrons and ions. Meanwhile, abundant active sites for redox reactions are generated and the structural endurance together with chemical stability of material is improved, thus strongly enhancing the electrochemical characteristics. When measured in a typical three-electrode cell, NiCo-LDH/Mn3O4 demonstrates a high specific capacity of 1.86 C cm−2 (1034.33 C g−1) at the current density of 1 mA cm−2, a superior rate capability of maintaining 76.88% at 20 mA cm−2 and 17.98% capacity loss after 5000 cycles. In addition, an all-solid-state hybrid supercapacitor device (HSC) is fabricated with NiCo-LDH/Mn3O4 as the cathode and commercially-used active carbon as the anode, which delivers a superior energy density of 57.03 Wh kg−1 at the power density of 765.8 W kg−1 and maintains 20.98 Wh kg−1 even when the power density increases to 9681.6 W kg−1. Therefore, the satisfactory electrochemical property enables NiCo-LDH/Mn3O4 to become a prospective electrode material in energy storage field. •We first synthesize a 3D partially-cladding NiCo-LDH/Mn3O4 composite.•The integration of nanosheets and nanoneedles improves the stability.•We first define and use the curve of accumulative contribution versus potential.•The NiCo-LDH/Mn3O4//AC HSC device shows high energy density and power density.