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Transition metal sulfides derived from metal‐organic frameworks (MOFs) have received increasing attention as a potential energy storage electrode material. Here, a series of NiS2/CoS2/NC‐T (T=temperature) have been successfully constructed by carbonizing and sulfuring the precursor of Ni/Co‐MOF. It is worth emphasizing that N‐doped carbon materials improve the conductivity of the electrode material. Moreover, NiS2/CoS2/NC‐500 maintains the rod‐like structure of the precursor and exhibits a high specific capacitance of 1325 F g−1 at a current density of 1 A g−1. Apart from high capacitance, the NiS2/CoS2/NC‐500 also demonstrated excellent cycling stability with retention rate of 75 % after 5000 cycles at a current density of 5 A g−1. The good performance could be attributed to the unique rod‐like structure and pore‐size distribution of NiS2/CoS2/NC‐500. Moreover, an assembled asymmetric supercapacitor NiS2/CoS2/NC‐500//AC displays a high energy density of 53.93 Wh kg−1 at a power density of 800 W kg−1 and good cycle stability with capacitance retention of 85.71 % after 20,000 cycles at 5 A g−1. In particular, a red LED can be illuminated by the assembled ASC, indicating that as‐synthesized NiS2/CoS2/NC‐500 hold great potential for practical applications. [ABSTRACT FROM AUTHOR]

Polyoxometalates (POMs), as multinuclear metal oxide clusters, possess natural multi-electron redox properties and high electrical conductivity. However, their susceptibility to leaching and agglomeration limits their application in energy storage. MOF materials provide a solution to the limitation of POMs due to their controllable pore sizes, big surface areas and strong adsorption properties. The synergistic effect between the two components greatly improves the electrochemical properties of the composites. In view of this, PMo 12 is encapsulated in ZIF-67 to form PMo 12 @ZIF-67 by in situ self-assembly, and benefitted from this unique precursor, MoSe 2 /(Ni, Co)Se 2 hollow structures assembled by nanoparticles are synthesized though Ni2+ etching and selenization process. At the same time, the PMo 12 content is optimized to get the best performance of 60-MoSe 2 /(Ni, Co)Se 2. In the three-electrode test, the developed 60-MoSe 2 /(Ni, Co)Se 2 electrode material exhibits an excellent specific capacity of 359.9 mA h g−1 at a current density of 1 A g−1, and a capacitance retention rate of 83.7 % after 10,000 cycles. In addition, the asymmetric supercapacitor (ASC) assembled with a positive electrode of 60-MoSe 2 /(Ni, Co)Se 2 and a negative electrode of activated carbon exhibits an excellent energy density of 40.3 W h kg−1 at a power density of 800.9 W kg−1. These superior electrochemical properties are attributed to the unique electronic structure of PMo 12 , which further demonstrates the feasibility of constructing hollow multicomponent selenides as energy storage materials using PMo 12 -ZIF-67 as a precursor. [Display omitted] • Successful construction of hollow MoSe 2 /(Ni, Co)Se 2 nanomaterial by in situ self-assembly. • 60-MoSe 2 /(Ni,Co)Se 2 exhibits a high specific capacitance of 359.9 mA h g−1 at 1 A g−1. • The ASC device displays a high energy density of 40.3 Wh kg−1 at 800.9 W kg−1. • The assembled ASC device keeps 89.6 % of its initial capacity after 10,000 cycles. [ABSTRACT FROM AUTHOR]

As a kind of energy storage device, supercapacitors have attracted the attention of researchers, and the development of high-performance electrode materials is also the focus of attention. In this paper, template synthesis and pyrolysis were combined to prepare high performance porous carbon electrode materials. The carbonized electrode material effectively increased the capacitance storage capacity and charge transfer rate. The results revealed that the derivative had a relatively low charge-transfer resistance and high specific capacitance of 1059 F·g−1 at a current density of 1.0 A·g−1 in a three-electrode system. To further exploring practical application, a device based on the derivative and hemp-activated carbon asymmetric supercapacitor was assembled in 0.1 M Na 2 SO 4 neutral electrolyte, which exhibited an energy density of 20.35 Wh·kg−1 at a power density of 400 W·kg−1. Interestingly, it showed capability retention of nearly of 91.7% and columbic efficiency of 100% even after 10000 charging/discharging cycles in the neutral electrolyte. Image 1 • The aqueous NPCZ-3//HAC ASC is assembled in 0.1 M Na 2 SO 4 neutral electrolyte. • Both cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) curves of ASC display pip symmetric characteristic. • The as-assembled ASC delivers a nearly of 91.7% capability retention after 10000 cycles. • The ASC delivers has a coulomb efficiency of 100% after 10000 cycles in a neutral electrolyte. [ABSTRACT FROM AUTHOR]

In this article, a trimesic acid-mediating control synthesis strategy was proposed for preparing the NiCo-MOF composition structure of microsphere and nanosheet by substituting 1,4-dicarboxybenzene with trimesic acid. Then the pre-synthesized MOF, as a precursor and template, was further vulcanized by a facile hydrothermal method to obtain hollow microsphere and nanosheet interleaved nickel and cobalt bimetallic sulfide materials (NiCo-S) while these microspheres and nanosheets were composed of smaller nanoparticles. This unique structure endowed quick electron/ion transport and electrolyte penetration as well as abundant redox active sites, significantly facilitating electrochemical performance. The obtained NiCo-S-2 showed higher specific capacitance (1790.4 F g−1) than its precursor NiCo-MOF-2 and other molar ratios of counterparts. Using it as an positive electrode and activated carbon (AC) as negative electrode, the assembled asymmetric supercapacitor NiCo-S-2//AC also delivered a high specific capacitance of 114.4 F g−1 and big specific energy of 35.5 Wh kg−1 at 799.99 W kg−1. • A ligand mediated control synthesis strategy was used for NiCo-MOF preparation. • Hollow microsphere and nanosheet interleaved structural NiCo-S had high specific capacitance (1790.4 F g−1). • NiCo-S-2//AC ASC delivered a high energy density of 35.5 Wh kg−1 at at 799.99 W kg−1. [ABSTRACT FROM AUTHOR]

Considering the high electrical conductivity of carbon dots (CDs) and good oxidation-reduction property of polyoxometalates (POMs), a novel CDs coated POMs /metal organic frameworks (POMOFs) composition structure, CDs@PMo 12 /Ni-MOF, was prepared by hydrothermal reaction in this work. PMo 12 was encapsulated in the Ni-MOF framework to form the POMOF composite material, which realized the fixation of water-soluble [PMo 12 O 40 ]3- (PMo 12). A comparison study on the cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) of the resulting CDs@PMo 12 /Ni-MOF with different compositions revealed that 6CDs@PMo 12 /Ni-MOF was better formulation in terms of specific capacity (748.8 C·g−1 at 1 A·g−1) and rate performance (75.93 % at 10 A·g−1). Furthermore, a hybrid supercapacitor device was assembled using 6CDs@PMo 12 /Ni-MOF as positive electrode and activated carbon (AC) as negative electrode, which showed an high energy density of 39.22 Wh·kg−1 under 749.9 W·kg−1 and excellent cyclic stability (98.4 % for 20000 cycles at 5 A·g−1). [Display omitted] • Fixation of water-soluble PMo 12 was realized to form POMOF composite material. • CDs@PMo 12 /Ni-MOF has excellent rate performance and cycle stability. • 6CDs@PMo 12 /Ni-MOF exhibits high specific capacitance and energy density. [ABSTRACT FROM AUTHOR]

• A simple ultrasound-assisted method was used to synthesize nitrogen-containing p - π conjugated-organic ligands. • Nitrogen-containing conjugated organic ligands have good conductivity. • Carbon-enriched MOFs and derived porous carbon have excellent electrochemical performance. • The change law of electrochemical performance was explored with gradient temperature. • The MOF-B-600//AC ASC device exhibits a high energy density of 63.62 Wh·kg−1 at power density of 400 W·kg−1. [Display omitted] This article aims to use nitrogen-doped metal p - π conjugated-organic frameworks and derived carbon-rich electrode materials for high-performance electrode materials. Nitrogen-doped contributes to the energy storage performance, and the p-π conjugated-organic ligands of the conjugated system can not only improve the stability of the structure, but increase the conductivity of the material. Gradient carbonization can explore the maximum electrochemical potential of MOF-B, from which the previous 1271.0 increased to 2727.5 F·g−1 at a current density of 1.0 A·g−1. The excellent capacitance retention rate is 86.67% of the initial value at a high current density after 20,000 cycles. Besides, the MOF-B-600//AC also shows a high energy density of 63.62 Wh·kg−1 at a power density of 400 W·kg−1 and good coulomb efficiency of 90.7%. As a result, the excellent electrochemical performance of the nitrogen-doped and carbon-enriched MOF-B-600 has potential application prospects in energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS 2 @Ni-MOF was prepared and alkalized to obtain MoS 2 /Ni(OH) 2. • MoS 2 /Ni(OH) 2 has high specific capacitance and long cycling life for supercapacitor. • MoS 2 /Ni(OH) 2 was used to construct electrochemical sensor for HQ and CC. A nickel-based metal-organic framework (Ni-MOF) layer was in situ grown on the surface of the sheet MoS 2 to synthesize MoS 2 @Ni-MOF as a precursor. In order to improve the properties of the precursor material, the final MoS 2 /Ni(OH) 2 material was obtained by alkalizing the precursor material. Supercapacitors and electrochemical sensors were prepared by MoS 2 /Ni(OH) 2 composite material. The test indicates that alkaline treatment of Ni-MOF materials is helpful to improve electrochemical performance. MoS 2 /Ni(OH) 2 material used as supercapacitor electrode has a high specific capacitance of 2192 F g−1 and excellent cyclic stability (the capacitance retention rate remains 85.19% after 10,000 charge/discharge cycles). The hybrid supercapacitor (HSC) was assembled with MoS 2 /Ni(OH) 2 as the positive electrode and activated carbon as the negative electrode. The MoS 2 /Ni(OH) 2 //AC HSC device shows an excellent energy density of 50.58 Wh kg−1 at the power density of 800 W·Kg−1. In addition, the MoS 2 /Ni(OH) 2 modified GCE electrode is an excellent electrochemical sensor for the simultaneous determination of hydroquinone (HQ) and catechol (CC). The modified electrode provides wide linear ranges of 1 ∼ 500 and 2 ∼ 400 μM and low detection limits of 0.43 and 0.48 μM for HQ and CC, respectively (S/N=3). The MoS 2 /Ni(OH) 2 material can be applied to supercapacitors and electrochemical sensors, indicating that the material has great potential application value in energy storage and biosensing. [ABSTRACT FROM AUTHOR]