Hierarchical network-like Ni-Mn-S/NiMn-LDH nanostructure as efficient electrode material for high-rate and long cycle life hybrid supercapacitors

Abstract

In the present work, we have developed a facile binder-free approach to design a hierarchical network-like nanostructure electrode onto the nickel foam (NF) using the combination of hydrothermal synthesis followed by an electrochemical deposition route. Based on the physicochemical properties and the electrochemical measurements, the integrated Ni-Mn-S/NiMn-LDH electrode delivers an extremely good specific capacitance of 2611.8F/g at 1 A/g and superior cyclic stability with 90.7 % capacitance retention after 10,000 cycles, along with 98.9 % coulomb efficiency. Accordantly, benefiting from the combination of structural and compositional advantages along with the multivalent state of Ni and Mn elements provide more active sites, prominent synergy, and short ion transport paths, which impressively improved the electrochemical performance of Ni-Mn-S/NiMn-LDH. Likewise, the assembled Ni-Mn-S/NiMn-LDH/NF//AC asymmetric device displays an excellent electrochemical behavior with a high energy density of 60.9 Wh kg−1 at a significant power density of 800 W kg−1 alongside the superior life-stability. Furthermore, nine blue LED indicators can be lit up for 1500 s when two ASCs connected in parallel. These results render an optimistic prospect of the Ni-Mn-S/NiMn-LDH in electrode materials for practical application in developing energy storage systems.