Bi-metal organic framework nanosheets assembled on nickel wire films for volumetric-energy-dense supercapacitors

Metal organic frameworks are regarded as promising electrode material for supercapacitors, however, low conductivity and pulverization hinder their application as free-standing film electrodes for high-performance supercapacitors. Herein, we demonstrate a core-sheath structured film electrode based on bi-metal organic framework nanosheets assembled on Ni wire for energy-dense supercapacitors. Dual metal-based vertically oriented metal organic frameworks nanosheets assembled on Ni wires can offer high surface areas, structure stability, as well as high conductivity, capacity, and rate capability. The as-fabricated Ni@CoNi-MOF film electrode delivers a specific capacity of 813C cm(-3) at 0.5 A cm(-3) and a high rate performance of 325C cm(-3) at 5 A cm(-3). Moreover, the assembled hybrid supercapacitor based on Ni@CoNi-MOF film (positive electrode) and graphene/carbon nanotube hybrid film (negative electrode) exhibits a high volumetric capacitance of 100 F cm(-3) at 0.5 A cm(-3) and an high energy density of 31.3 mWh cm(-3) with the power density of 3769.4 mW cm(-3). Remarkably, capacitance of as-assembled hybrid supercapacitor device retains 100% after 10000 cycles at 3 A cm(-3), indicating a long cycling stability. The concept design of this work can give an insight for engineering metal organic frameworks based or other similar electrode materials for volumetric-energy dense supercapacitors.