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

A NiCo-LDH/Mn 3 O 4 composite is synthesized on nickel foam substrate though a two-step electrodepositon process. The growth of Mn 3 O 4 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/Mn 3 O 4 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/Mn 3 O 4 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/Mn 3 O 4 to become a prospective electrode material in energy storage field. • We first synthesize a 3D partially-cladding NiCo-LDH/Mn 3 O 4 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/Mn 3 O 4 //AC HSC device shows high energy density and power density. [ABSTRACT FROM AUTHOR]