One-Step Electrochemical Synthesis of Co_0.8Fe_0.2Se@NiF Spheres Enclosed with Nanoparticles and Integrated Porous FeSe₂@NiF as Electrode Materials for High-Performance Asymmetric Supercapacitor

Herein, we offer a new method to prepare Co0.8Fe0.2Se spheres enclosed with nanoparticles (Co0.8Fe0.2Se@NiF) as a cathode electrode and integrated porous FeSe2 (FeSe2@NiF) as an anode electrode to construct a high-performance asymmetric supercapacitor. The Co0.8Fe0.2Se@NiF electrochemical energy storage material shows a remarkable improvement of electrochemical performance containing low internal resistance, fast kinetics, good reversibility, considerable durability, and significant specific capacity (SC) of 309.31 mAh g–1. The advancement in electrochemical performance of the FeSe2@NiF subtends a good SC of 227.34 mAh g–1 and favorable durability. An asymmetric supercapacitor (ASC) device comprised of Co0.8Fe0.2Se@NiF as a cathode and FeSe2@NiF as an anode was assembled and evaluated. The assembled device shows an SC of 108.52 mAh g–1 and energy density (ED) of 89.53 Wh kg1– at a power density (PD) of 824.95 W kg1–. This improved electrochemical performance is dependent on the structural and intrinsic properties of both electrode materials, which can guarantee a hopeful potential for later generations of electronic systems

Cobalt-molybdenum selenide double-shelled hollow nanocages derived from metal-organic frameworks as high performance electrodes for hybrid supercapacitor

In this paper, we developed a sequential chemical etching and selenization processes to synthesize Co-MoSex double-shelled hollow nanocages (CMS DSHNCs) as high performance electrode materials for supercapacitor applications. Co-MoOx yolk-shelled hollow nanocages were firstly synthesized using a solvothermal process through facile ion-exchange reactions between zeolitic imidazolate framework-67 (ZIF-67) and MoO42- ions. By applying a solvothermal temperature of 160 oC in the presence of SeO32- and subsequently annealing strategy, CMS-DSHNCs were successfully synthesized with a yolk-shell hierarchically hollow and porous morphology of mixed metal selenides. The CMS-DSHNCs exhibit superior electrochemical properties as electrode materials for supercapacitor: e.g., a specific capacity of 1029.8 C g-1 at 2 A g-1 (3.089 C cm-2 at 6mA cm-2), a rate capability of ~76.14, a capacity retention at 50 A g-1, and a good cycle stability (95.2 capacity retention over 8000 cycles). A hybrid supercapacitor was constructed using the CMS-DSHNCs as the cathode and activated carbon (AC) as the anode in a solution of 3 M KOH, and achieved a high specific energy of 45 Wh kg−1, and a specific power up to 2222 W kg−1 with a good cycling stability of 94 after 8000 cycles

Evaluation of charge storage ability of chrome doped Mn2O3 nanostructures derived by cathodic electrodeposition

A facile synthetic route has been proposed to prepare cauliflower-like nanostructures of Cr doped Mn2O3. The synthesis was carried out by constant current cathodic electrodeposition from Mn2+ nitrate solutions containing minor amounts of dichromate. It was found that the presence of Cr mediates the formation of cathodic MnO2 which then reacts with the excess Mn2+ species to form Mn2O3 nanostructures. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to characterize the nanostructures. The storage ability of the obtained nanostructures was investigated by cyclic voltammetry (CV) in 0.5 M Na2SO4 solution. The results indicated that the Cr doped manganese oxide material shows better performance than the non-doped one, and the charge capacity (SC) of doped manganese oxide (218 F/g) was higher than pure manganese oxide (208 F/g)