Facile synthesis of a three-dimensional Ln-MOF@FCNT composite for the fabrication of a symmetric supercapacitor device with ultra-high energy density: overcoming the energy storage barrier

In order to quench the thirst for efficient energy storage devices, a novel praseodymium-based state-of-the-art three-dimensional metal-organic framework (MOF), {[Pr(pdc)2]Me2NH2}n (YK-1), has been synthesized by using a simple solvothermal method employing a readily available ligand. YK-1 was characterised by single-crystal XRD and crystallographic analysis. The electrochemical measurements of YK-1 show that it exhibits a specific capacitance of 363.5 F g-1 at a current density of 1.5 A g-1 with 83.8% retention after 5000 cycles. In order to enhance its electrochemical performance for practical application, two composites of YK-1 with graphene oxide (GO) and functionalised multi-walled carbon nanotubes (FCNTs), namely YK-1@GO and YK-1@FCNT, were fabricated by employing a facile ultrasonication technique. The as-synthesized MOF and the composites were characterized by PXRD, FTIR, SEM, and TEM techniques. YK-1@GO and YK-1@FCNT offer enhanced specific capacitances of 488.2 F g-1 and 730.2 F g-1 at the same current density with 93.8% and 97.7% capacity retention after 5000 cycles, respectively (at 16 A g-1). Fascinated by the outstanding results shown by YK-1@FCNT, a symmetric supercapacitor device (SSC) based on it was fabricated. The assembled SSC achieved a remarkable energy density (87.6 W h kg-1) and power density (750.2 W kg-1) at a current density of 1 A g-1, along with very good cycling stability of 91.4% even after 5000 GCD cycles. The SSC device was able to power up several LED lights and even operated a DC brushless fan for a significant amount of time. To the best of our knowledge, the assembled SSC device exhibits the highest energy density among the MOF composite-based SSCs reported so far.

Recent progress in 1D MOFs and their applications in energy and environmental fields

Metal organic frameworks (MOFs) are porous coordination polymers with adjustable nanostructure, high porosity and large surface areas. These features make MOFs, their derivates and composites all delivered remarkable potential in energy and environmental fields, such as rechargeable batteries, supercapacitors, catalysts, water purification and desalination, gas treatment, toxic matter degradation, etc. In particular, one-dimensional (1D) MOFs have generated extensive attention due to their unique 1D nanostructures. To prepare 1D MOF nanostructures, it is necessary to explore and enhance synthesis routes. In this review, the preparation of 1D MOF materials and their recent process applied in energy and environmental fields will be discussed. The relationship between MOFs' 1D morphologies and the properties in their applications will also be analyzed. Finally, we will also summary and make perspectives about the future development of 1D MOFs in fabrication and applications in energy and environmental fields.

A novel self-supported structure of Ce-UiO-66/TNF in a redox electrolyte with high supercapacitive performance

A novel self-supported structure of Ce-UiO-66/TNF was firstly synthesized by growing Ce-UiO-66 on a TNF substrate. This novel Ce-UiO-66/TNF material was proved to possess a high supercapacitive performance in the redox electrolyte of Fe(CN)₆^3-/^4-, and it was also the first study for Ce-UiO-66 material on the supercapacitor application. High specific capacitances of 6.9 and 2.5 Fcm^-2 can be achieved at large current densities of 20 and 80 mAcm^-2, respectively. After 10,000 charge-discharge cycles, the capacitance retention can be kept at 95% and the coulomb efficiency can be maintained over 98%. Such outstanding electrochemical performance may be related to the redox property of the electrolyte, high specific surface area of the Ce-UiO-66 material, porous characteristic of the TNF substrate and self-supported structure of the whole electrode.

Dual Functionalized CuMOF-Based Composite for High-Performance Supercapacitors

Herein, we utilized our previously reported highly porous CuMOF, {[Cu₂(L)(H₂O)₂]·(5DMF)·(4H₂O)}_n, decorated with amine and trifluoromethyl functional groups for energy storage application. This robust framework in CuMOF enhances the chemical and thermal stabilities as well as improves the interfacial binding interactions. The poor conductivity of CuMOF usually restricts its practical utility in energy storage systems, due to which rGO was introduced along with CuMOF to form a CuMOF/rGO composite (1) through a facile ultrasonication technique. The synergistic effects between CuMOF and rGO induce a dramatic enhancement in specific capacitance (462 F g^-1 at 0.8 A g^-1) of 1 with a cycle life of 93.75% up to 1000 cycles. The results highlight 1 as an emerging contestant for next generation supercapacitors.

A silver nanoparticle-anchored UiO-66(Zr) metal–organic framework (MOF)-based capacitive H2S gas sensor

Metal–organic frameworks anchored with metal oxide nanoparticles for the detection of H₂S gas with enhanced sensitivity.

Engineering PPy decorated MnCo2O4 urchins for quasi-solid-state hybrid capacitors

In this work, three dimensional PPy decorated MnCo₂O₄ urchins on Ni foam are fabricated via a hydrothermal strategy and an electro-polymerization process.

Optimizing crystallinity and porosity of hierarchical Ni(OH)2 through conformal transformation of metal–organic framework template for supercapacitor applications

Conformal hydrolysis of MOFs (metal–organic frameworks) yields high-performance supercapacitor electrodes.