Facile Preparation of a Ni/Mn-LDH Nanosheet @Graphene Foam Hierarchical Structure for High-performance Flexible Supercapacitors

Abstract In this study, a novel Ni/Mn-LDH nanosheets array @graphene foam nanocomposite is fabricated via an in-situ self-assembled strategy through the facile hypothermal chemical coprecipitation, which can work at relatively low temperature (55 °C) and atmospheric pressure distinct from common hydrothermal process. Neither surfactant nor stabilizer is employed to produce the three-dimensional hierarchical architecture, which is composed of interconnected nanosheets network encapsulating graphene foam. The prepared mechanism is ascribed to stepwise reaction of nanoparticles growing to nanopetals and then assembling into nanosheets-network. Benefiting from the special configuration, the electrode demonstrates favorable electrochemical properties with a capacitance of 2380 F·g−1 (1 A·g−1) and 1315 F·g−1 reserved even at 20 A·g−1. The derivative all-solid-state asymmetric supercapacitor displays high energy density and power density of 134.83 Wh·kg-1 and 1.01 kW·kg-1 with cycling stability of 94.9% remaining after 1000 cycles. That performance makes it be of great prospects of the application in future wearable devices.