In Situ Growth of Ni-Doped Co-MOF-74 on Ni Foam for High-Performance Electrochemical Energy Storage

The application of conventional metal organic frameworks (MOFs) as a battery-type electrode is largely hindered by their poor conductivity, low capacity and weak adhesion to substrate. To overcome these obstacles, Ni-doped MOF-74 containing Co (Ni/Co-MOF-74) are in situ grown on Ni foam by one-step solvothermal method as binder-free electrode for electrochemical energy storage. In the three-electrode system, the Ni/Co-MOF-74 electrode (Ni: Co = 5: 10) exhibits larger specific capacity (433.5 C g−1 at 1 A g−1) and better rate capability (359.1 C g−1 at 10 A g−1). Such a superior electrochemical performance may be attributed to the rich porous structure, good conductivity, and sufficient redox reaction through synergistic effect of Ni and Co dual-metal, as well as the good mechanical adhesion to Ni foam. Furthermore, a hybrid device based on porous Ni/Co-MOF-74 and activated carbon (AC) exhibits high specific capacity of 117.0 C g−1 at a current density of 1 A g−1, and shows an high energy density of 24.4 W h kg−1 at a power density of 784.2 W kg−1. Additionally, two hybrid devices in series can light up a red light-emitting diode (LED) for more than 60 s.