| Supercapacitors,also known as ultracapacitors or electrochemical capacitors（ECs）,are electrochemical devices that stores charge at the interface between the electrode and the solution through a polarized electrolyte.As a new type of energy storage device,it has attracted much attention in the field of communication equipment,wearable electronic devices,backup power systems and hybrid vehicles due to its unique high power density,fast charge and discharge speed,long cycle life,and low pollution.Electrode material is one of the important components of supercapacitors,and also an important factor affecting the performance of supercapacitors.With the rapid development of nanocomposite materials,the construction of novel and multi-functions electrode materials has become the trend of supercapacitors.Metal-organic frameworks（MOFs）,are a class of crystalline material formed by the coordination of metal ions and organic polydentate ligands,MOFs has always been regarded as the excellent electrode material for series energy storage devices such as supercapacitors and batteries,due to its controllable morphology,abundant pores,large specific surface area,and functional diversity.Unfortunately,most of the MOFs have low electrical conductivity,which greatly limits their applications in the field of supercapacitors.In this paper,we prepared a series of MOFs-based electrode materials and explored their electrochemical properties as electrode materials in supercapacitors.The main content is as follows:1.Two-dimensional conductive MOFs of two different metals,HTTP-Co-CC,HTTP-Ni-CC,with hexamercaptotriphenylene as an organic polydentate ligand were designed and synthesized,and the prepared material were characterized and identified,the structural characteristics of conductive MOFs were determined through scanning electron microscopy（SEM）and high-resolution transmission electron microscopy（TEM）,combined with the detection of XRD patterns,Raman spectra,infrared spectra and XPS energy spectra,further,we investigated electrochemical properties of conductive MOFs as electrode materials in supercapacitors in the-60 to 20oC temperature range.MOFs nanoparticles are pressed into microchips with high packing density close to crystals(1.35-1.39 g·cm-3)by isostatic pressing technology,and monitored the resistivity of the electrode material at different temperatures of HTTP-Co,found that the material exhibits good conductivity at low temperatures,compared with traditional electrode material activated carbon electrode（AC）,at-60oC,HTTP-Co-CC(90.75 F·g-1),HTTP-Ni-CC(119.05 F·g-1)are all exhibited better capacitance performance than AC(28.3 F·g-1),Compared with the room temperature capacitance,the HTTP-M-CC capacitance retention rate is about 92%and 97%,while the AC only reaches 22%of the initial capacitance.These results indicate that the multilayer pore size conductive MOFs as electrode materials dispaly excellent electrochemical performance for low-temperature capacitors,providing a certain experimental basis for realizing the reliable operation of electric double-layer capacitors in a larger temperature range.2.Design a simple and controllable electrochemical co-deposition method to prepare the multi-component hierarchical hollow microcapsule nanocomposite PCN-224@PEDOT/PMo12-CC.We skillfully intorducted conductive polymer PEDOT to improve the overall conductivity of the electrode material,at the same time,the introduction of the"electron sponge"polyoxometalate phosphomolybdic acid[PMo12O40]3-(PMo12),which has a large electron transfer ability,is also regarded as a contributor to capacitance.PEDOT and[PMo12O40]3-(PMo12)are co-woven with the ultra-stable and high-porosity MOFs（PCN-224）to form microcapsules,this microcapsules provides additional specific surface area for the material,and a buffer space for the volume expansion caused by the reaction of the electrode material.The unique structural characteristics make PCN-224@PEDOT/PMo12-CC material show excellent electrochemical performance,When the current density is 5 m A·cm-2,the area capacitance can reach 4077.8 m F·cm-2,in addition,the PCN-224@PEDOT/PMo12-CC is assembled into an all-solid symmetrical flexible supercapacitor as electorde material,which exhibits high energy density and power density.The device shows excellent cycle stability performance,after 10,000 cycles,the capacitance is only 15.41%attenuation.This work proposes a one-step electrodeposition synthesis strategy for the design and construct high-capacitance electrode materials based on MOFs,and shows great prospects in the design of high-performance materials and the production of advanced energy.3.Hollow POMs@MOFs nanocomposites grown in situ on a conductive substrate was prepared,which based on molybdenum-containing heteropolyacids（Mo-POMs,polyoxometalates）and zirconium-based metal organic framework,and POMs@MOFs was used as a template to recombine the classic covalent organic framework（COFs）Tp Pa-1material and then pyrolysis treatment,the Mo O2@Zr O2@NAWS nanocomposites with Mo2C doped nanowire arrays wrapped in core-shell structure was prepared.The electrochemical performance test shows that,the area specific capacitance of Mo O2@Zr O2@NAWS/CC-II is 4380.5 m F·cm-2 at the current density is 2 m A·cm-2.Subsequently,the electrode materials were assembled into an all-solid asymmetric supercapacitor.At a current density of 6 m A·cm-2,the area specific capacitance was 987.3m F·cm-2,and the capacitance retention rate after 10,000 cycles of charging and discharging was 88.64%,it shows that the asymmetric supercapacitor Mo O2@Zr O2@NAWS//PVA（KOH）//AC has excellent rate discharge performance and cycle stability. |
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