Facile synthesis of cobalt, nickel and manganese-based metal organic framework derived layered double hydroxides on Ni foam as effective binder-free electrodes of energy storage devices

Metal organic framework (MOF) derivatives have attracted intensive attention as the active material of energy storage devices. Layered double hydroxide (LDH) with large surface area, high redox capability and good cycling stability is regard as one of efficient active materials. Developing MOF-derived LDH with multiple metals can possibly achieve excellent surface properties, high electrical conductivity and abundant redox reactions. However, synthesizing MOF-derived LDH is time-consuming and requires high temperature environments. In this work, a simple and time-effective precipitation and etching process is proposed to synthesize MOF-derived LDH on nickel foam (NF) as binder-free electrodes of energy storage devices. The cobalt, nickel and manganese are utilized to design MOF-derived LDH with different metal species and numbers. The trimetallic MOF-derived LDH based on Co, Ni and Mn presents a high specific capacitance (C_F) of 1113.7 F/g at 20 mV/s, due to abundant electroactive sites and multiple redox states for carrying out large numbers of redox reactions. The energy storage device composed of the trimetallic MOF-derived LDH and carbon on NF as electrodes presents the maximum energy density of 61.5 Wh/kg at the power density of 750 W/kg, and the C_F retention of 92.5% and Coulombic efficiency of 95% after 10,000 charge/discharge cycles.