Efficient Ultrasonic Synthesis of Ni‐Based Metal–Organic Framework for High Performance Battery‐Type Supercapacitor Electrodes

Abstract

Metal-organic frameworks (MOFs) as an emerging kind of poriferous crystalline compounded material, the preparation and applications including gas storage, [1,2] catalysis, [3] separation, [4] drug delivery, [5,6] and chemical sensors [7] of its new porous structure has achieved tremendous development in the past few decades. Co8-MOF-5 was first reported as electrode materials for supercapacitors (SCs). MOFs with large specific surface area attribute to high rate of holes that can reserve ample electric charge and promote the dispersion of electrolyte ions as well as provide plentiful faradaic redox centers. [8] Therefore, more and more MOFs used as electrode materials have been rapidly developed. It was Yang et al. first published that a 2D nickel-based MOF has excellent current capability (providing a high specific volume of 1127 F g À1 at 0.5 A g À1 ) and outstanding cycle durability (over 90% capacitance retention after cycling 3000 times). [9] The synthesis of unique flower-like structure Ni-MOFs has been reported, which produced a high pseudo capacity of 1457.7 F g À1 at 1 A g À1 . [10] However, currently, most Ni-MOFs with high capability and unique morphology are synthesized by solvothermal method. On various occasions, solvothermal requires a long reaction time of up to several days. Moreover, the reaction of the frame members must be carried out at high temperatures (usually 373-523 K) and pressure (1-10 MPa). Considering the great capability of MOFs to be used in SCs in the future, some more effective and new synthesis techniques for substitution should be developed as soon as possible. What is more, the adoption of high-duty ultrasound (US) can provide a convenient, environmental, and commonly used compositing tool for MOFs materials.US causes chemical changes based on cavitation phenomena, involving the sequential generation, rising, and succedent collapse of bubbles in hot spots. [11][12][13] More specifically, when radiated by the US, the alternating expansion sound wave and compression sound wave will produce bubbles, and the vibratory blisters can amass US power to a particular amount (tens of millimeters). The bubbles will grow excessively in a very short life (heating and cooling rates > 1010 K s À1 ) and then collapse. [14][15][16] A great concentration of energy was obtained in the course of the eruption, bringing a certain temperature at a certain part of about 5000 K and a pressure of about 1000 bar. This power will be diffused into the surroundings during the collapsing, so the temperature of the gas at the important point will quickly renew to the value of the surroundings and its rates of heating/cooling will return to up 1010 K s À1 . [17] Because of such factors, US irradiation make it possible to get sufficient amounts of energy to achieve the reaction which is previously hard to get with other approaches. even macroscopically at room temperature. In detail, the first synthesis material came into being in 2008 by Qiu et al. with (Zn 3 BTC 2 12H 2 O). [18]

Conductive Bismuth-Catecholate Metal–Organic Frameworks Grown on Ti3C2Tx Nanosheets for High-Performance Supercapacitors

“…In GCDs (Figure 5d), all curves exhibit similar plateaus, which closely correspond to the redox peaks observed in CVs. 59 According to the GCDs, the specific capacitances in the two-electrode system are calculated to be 71.3, 53.3, 53.3, 50.0, 39.5, and 32 F g −1 at current densities of 1, 2, 4, 5, 8, and 10 A g −1 , respectively, as shown in Figure 5e. The EIS plot of the aqueous device reveals an ESR of 2.4 Ω cm −2 and a quasivertical low-frequency straight line (Figure 5f), a typical characteristic of supercapacitors meaning the facile accessibility between the electrolyte and the electrodes.…”

Advances of Electroactive Metal–Organic Frameworks

“…[128,130] Particularly, pristine MOF electrode materials with Faradic reactions have developed rapidly over past years. Among which, monometallic MOFs including Ni MOFs, [263][264][265][266] Co MOFs, [267][268][269] Fe MOFs, [270] Mn MOFs, [271] and Zr MOFs [272] and bimetallic MOFs such as NiCo MOFs [273][274][275][276] were heavily investigated. Organic linkers were narrowly targeted at carboxylic acids with a focus on either H 2 BDC, L1, or H 3 BTC, L8, in addition to a few less commonly studied carboxylic acid linkers.…”

Recent Developments in Sonochemical Synthesis of Nanoporous Materials

“…Moreover, sonochemical methods are often utilized for the preparation of MOF-containing composites, e.g., with graphene derivatives [ 114 , 115 ]. SSA values and potential applications of MOFs and COFs obtained via sonochemical-assisted methods are summarized in Table 4 [ 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 ].…”