Freestanding hierarchical nickel molybdate@reduced graphene oxide@nickel aluminum layered double hydroxides nanoarrays assembled from well-aligned uniform nanosheets as binder-free electrode materials for high performance supercapacitors

Herein, the hierarchical nickel molybdate@reduced graphene oxide@nickel aluminum layered double hydroxides (NiMoO4@rGO@NiAl-LDHs) architecture assembled from well-aligned nanosheets is successfully constructed on Ni-foam through a three-step strategy. For the first time, ultrathin graphene nanosheets are introduced by a novel spraying process to avoid the stack. NiAl-LDHs is prepared via situ growth procedure in which NiAl-LDH self-assembles on the surface of graphene to prevent graphene from aggregating, resulting in an enlarged specific surface area. Electrochemical analysis manifests that NiMoO4@rGO@NiAl-LDHs yields exceptional specific capacitance (3396 Fg(-1) at 1 Ag-1), favorable charge/discharge rate and approving long-term stability. Furthermore, the NiMoO4@rGO@NiAl-LDHs//AC device delivers superior specific capacitance (137.2 Fg(-1) at 1 Ag-1), high energy density (48.7 Whkg(-1)) associated with pleasurable power output (7987 Wkg(-1)). Importantly, the well-aligned NiMoO4@rGO@NiAl-LDHs provides a prospective conception constructing hierarchical structural materials in the area of supercapacitor. (C) 2019 Elsevier Inc. All rights reserved.