In-situ synthesis of Ni-MOF@CNT on graphene/Ni foam substrate as a novel self-supporting hybrid structure for all-solid-state supercapacitors with a high energy density

Abstract

A new hybrid structure of Ni-MOF and CNT (Ni-MOF@CNT) was firstly in-situ synthesized on the graphene/Ni foam (GN) substrate and a novel self-supporting material of Ni-MOF@CNT/GN was obtained. Furthermore, its application as a new electrode material for all-solid-state supercapacitors was also investigated for the first time. An ultrahigh energy density of 0.3396 mWhcm−2 can be achieved as the best value reported for MOF-based all-solid-state supercapacitors to date. Moreover, high capacitance values of 898 and 230 mFcm−2 can be obtained at 1 and 20 mAcm−2, respectively, and a high retention value of 93% can be also maintained even after 4000cycles. Such a high electrochemical performance may be ascribed to high conductivity of the CNT, electron transport effect of the graphene layer, porous characteristic of the Ni-MOF@CNT/GN material and changes of oxygen-containing groups in the hybrid structure.