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

Abstract

In this work, a new 3D metal–organic framework (MOF) {[Co3(μ4-tpa)3(μ-dapz)­(DMF)2]·2DMF} n (Co­(II)-TMU-63; H2tpa = 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 (μ4-tpa2– and μ-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 Whkg–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.

Synthesis, structure and magnetic properties of a cobalt(II) mesoxalate 1D coordination polymer

“…The intensity of the magnetic coupling in 1 is comparable to that of [Ln 2 (H 2 mesox) 6 ] ⋅ 6H 2 O with the same bridging mode of the ligand. Finally, the obtained compound extends the family of functional Co(II) and Co(III) carboxylate‐driven coordination polymers [21–23] …”

Supercapacitor electrodes based on metal‐organic compounds from the first transition metal series

“…For SCs based on monometallic organic compounds, cobalt is the most commonly used metal in the first transition metal series 25,27,50,67,69,72,73,97‐134 . Summarized in Tables 3 and 4 are the electrode and SC performances of cobalt‐organic compounds and their composites ( 12 ‐ 92 ).…”

“…Cobalt polycarboxylate MOFs are the most popular cobalt‐organic compounds as electrode materials in SCs 25,27,50,67,72,73,97,99‐116,132 . H 2 BDC (Figure 4A) is one of the most typical polycarboxylate ligands and has been widely used to fabricate SC electrodes based on Co‐MOFs and their composites ( 13 ‐ 16 , 18 , 19 , 25 ).…”

Cd‐Based Metal–Organic Framework for Selective Turn‐On Fluorescent DMSO Residual Sensing

“…Compared with non‐porous sensors, MOFs are a new burgeoning crystalline material with metal nodes and organic ligands orderly assembled, featuring permanent porosity, extraordinarily high surface areas, tunable pore size, adjustable pore function etc., [10–14] attracting more and more attention in many fields such as gas adsorption, [15–17] catalysis, [18–23] energy storage, [24–25] drug delivery [26] and fluorescence detection [27–30] . Specifically, MOFs have proved to be promising sensors for detecting various analytes like metal ions, [31–36] inorganic anions [37–39] and small organic molecules [40–45] .…”