An Asymmetric Supercapacitor Based on a Non-Calcined 3D Pillared Cobalt(II) Metal-Organic Framework with Long Cyclic Stability

In this work, a new 3D metal-organic framework (MOF) {[Co-3(mu(4)-tpa)(3)(mu-dapz)(DMF)(2)]center dot 2DMF}(n) (Co(II)-TMU-63; H(2)tpa = terephthalic acid, dapz = pyrazine-2,5-diamine, DMF = dimethylformamide) containing low-cost and readily available ligands was generated, fully characterized, and used as an electrode material in supercapacitors without the need for a calcination process. Thus, the synthesis of this material represents an economical and cost-effective method in the energy field. The crystal structure of Co(II)-TMU-63 is assembled from two types of organic building blocks (mu(4)-tpa(2-) and mu-dapz ligands), which arrange the cobalt nodes into a complex layer-pillared net with an unreported 4,4,4,6T14 topology. The presence of open sites in this MOF is promising for studying electrochemical activity and other types of applications. In fact, Co(II)-TMU-63 as a novel electrode material when comparing with pristine MOFs shows great cycling stability, large capacity, and high energy density and so acts as an excellent supercapacitor (384 F g(-1) at 6 A g(-1)). In addition, there was a stable cycling performance (90% capacitance) following 6000 cycles at 12 A g(-1) current density. Also, the Co(II)-TMU-63//activated carbon (AC) asymmetric supercapacitor acted in a broad potential window of 1.7 V (0-1.7 V), exhibiting a high performance with 4.42 kW kg(-1) power density (PD) and 24.13 Wh kg(-1) energy density (ED). These results show that the pristine MOFs have great potential toward improving different high-performance electrochemical energy storage devices, without requiring the pyrolysis or calcination stages. Hence, such materials are very promising for future advancement of the energy field.