Addition of dissimilar metal nodes to improve the electrochemical performance of MOF as a supercapacitor

• A new trimetallic MOF with Ni 2+ , Co 2+ and Mn 2+ was hydrothermally synthesized. • The 3-D structure was elucidated via single crystal XRD technique. • MnCoNi-MOF has excellent electrochemical performance as a battery-type hybrid supercapacitor. Supercapacitors benefit from their high power density and long cycle life and are on the road of rapid development. Metal-organic framework (MOF) with abundant energy storage active sites (metal nodes, benzene-containing functional groups, pores and surface structure) has become a member of the library of supercapacitor electrode materials. However, the poor conductivity of most MOFs leads to unsatisfactory rapid charge and discharge capabilities and instability in cycles caused by uneven electron transfer. Here, we newly reported a three-dimensional trimetallic MOF (MnCoNi-MOF) based on 1,2,4,5-benzenetetracarboxylic acid ligand, which has better conductivity and larger specific surface area than monometallic MOF (Ni-MOF). Attributable to more active sites, MnCoNi-MOF as an electrode material has a specific capacitance of 655 F g −1 at 1 A g −1 , which is much higher than Ni-MOF (95 F g −1 ). In addition, benefiting from the multi-metal synergistic effect, MnCoNi-MOF also exhibits excellent rate performance and durability (92.3% capacity retention after 10,000 cycles). After assembled into a hybrid capacitor with activated carbon, it delivers an energy density of 61 Wh kg −1 at 844 W kg −1 , accompanied by a capacity decay of only 1.7% after 2000 cycles. The promising results prove that increasing the metal active center of MOF can greatly improve the energy storage performance. In the long term, this research would be expandable to a wide range of transition-organometallic materials for energy storage paradigm.