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The carbon nanotubes attached mesoporous Ag3O4-coated NiO nanosheets were prepared successfully through hydrothermal method. The structural, morphological and electrochemical properties of the prepared nanocomposite have been studied. The X-ray diffraction and Raman analysis confirms the presence of NiO, Ag3O4 and carbon nanotubes in the prepared sample. HRTEM images clearly show the coating of Ag3O4 on the NiO and attachment of carbon nanotubes. BET surface area analysis confirms the mesoporous nature of the prepared composite. The cyclic voltammetric (CV), galvanostatic charge-discharge (GCD) and impedance analysis were made to explore the electrochemical nature of the composite. Cyclic voltammograms reveals the maximum specific capacity of 415.86 mAh g−1 at the scan rate of 3 mV s−1 and GCD analysis exhibits the specific capacity of 416.63 mAh g−1 at 1 A g−1. The prepared nanocomposite retained 97% of maximum capacity even after 1500 cycles. [ABSTRACT FROM AUTHOR]

Transition metal oxide-based magnetic nanocomposites attract great attention due to their unique properties and applications in the field of energy storage. Herein, we present a facile microwave procedure for the synthesis of CuFe2O4 (CF) and CuFe2O4 incorporated with reduced graphene oxide CuFe2O4/rGO (CG) as potential electrode materials for hybrid supercapacitor. The structure and morphology of CF and CG nanoparticles are examined. The electrochemical performance is studied in 6 M aqueous KOH electrolyte using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The attractive CG nanocomposite exhibits high specific capacity of 800 C/g at a current density of 2 A/g and better cycling stability when compared to pure CF, due to the formation of nanostructure composed of ferrite nanoparticles homogeneously incorporated onto rGO sheets. Furthermore, the practicability of CG electrode is investigated by the fabrication of CG and activated carbon. The hybrid supercapacitor device shows excellent electrochemical performance with specific energy of 18.3 Wh/kg and a specific power of 455 W/kg. It is noteworthy that the cyclic stability is excellent with a capacity retention of ~98% after 3000 cycles manifesting the superiority of CG electrode. The proposed device demonstrates the potential to fabricate other metal oxides with activated carbon via a facile synthesis method for promoting application in energy storage materials and promoting new opportunities of binary nanocomposite. [ABSTRACT FROM AUTHOR]

Bismuth-based semiconductors have attracted significant attention in rechargeable batteries and supercapacitor devices. In this study, layered structured bismuth germanate (Bi12GeO20) was synthesized using hexamine as a surfactant, at 850 °C, and utilized as electro-active material for supercapacitor and sodium ion (NaB) storage applications. The physical characterization of the prepared Bi12GeO20 was studied with various characterization and microscopic analyses such as XRD, FT-IR, FESEM with EDS, HRTEM, and XPS analysis. The XRD analysis exposed the successful formation of a highly crystalline sillenite phase of Bi12GeO20. The surface morphology analysis FE-SEM and HR-TEM revealed the effective construction of the 2D layered structure of Bi12GeO20. The EDS results profound that uniform distribution of the Bi, Ge, and O elements with good elemental stoichiometry. The supercapacitor properties of the prepared Bi12GeO20 were evaluated with the help of three electrode method using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance (EIS) techniques in the aqueous solution of 3.0 M KOH. The prepared Bi12GeO20 architecture shows a higher specific capacitance of 355 F g−1, with a current density of 1 A g−1. Finally, the sodium-ion storage capacity of Bi12GeO20 was evaluated using a coin cell-type electrode. The as-synthesized Bi12GeO20 material was utilized as an anode for Na ion storage and demonstrated a high specific capacity of 740 mAh g−1 at 0.1 C rate. With these appreciable electrochemical performances, the single component Bi12GeO20 holds an ideal alternative electrode material to develop high-performance power and energy storage devices. [ABSTRACT FROM AUTHOR]

The study presents the binder-free synthesis of mixed metallic organic frameworks (MMOFs) supported on a ternary metal oxide (TMO) core as an innovative three-dimensional (3D) approach to enhance electron transport and mass transfer during the electrochemical charge-discharge process, resulting in high-performance hybrid supercapacitors. The research demonstrates that the choice of organic linkers can be used to tailor the morphology of these MMOFs, thus optimizing their electrochemical efficiency. Specifically, a NiCo-MOF@NiCoO 2 @Ni electrode, based on terephthalic linkers, exhibits highly ordered porosity and a vast internal surface area, achieving a maximum specific capacity of 2320 mC cm -2 , while maintaining excellent rate capability and cycle stability. With these performances, the hybrid supercapacitor (HSC) achieves a maximum specific capacitance of 424.6 mF cm -2 (specific capacity 653.8 mC cm -2 ) and 30.7 F cm -3 with energy density values of 10.1 mWh cm -3 at 167.4 mW cm -3 (139.8 µWh cm -2 at 2310 µW cm -2 ), which are higher than those of previously reported MMOFs based electrodes. This research introduces a novel approach for metal organic framework based HSC electrodes, diverging from the traditional emphasis on metal ions, in order to achieve the desired electrochemical performance., (© 2023 Wiley‐VCH GmbH.)

Supercapacitors (SCs) have emerged as attractive energy storage devices due to their rapid charge/discharge rates, long cycle life, and high-power density. However, the development of innovative electrode materials to achieve high-performance remains crucial to meet future requirements in supercapacitor technology. In this work, we have explored the potential of a microwave-engineered NiZrO 3 @GNP composite as a promising electrode material for SCs. A microwave assisted hydrothermal approach was adopted for the fabrication of the NiZrO 3 @GNP nanocomposite. Structural and morphological investigations showed its structural richness and its chemical compositions. When applied as a SC electrode, this innovative combination exhibits battery-like behaviour with higher specific capacity (577.63 C g -1 ) with good cyclic stability, and good performance. We have assembled an asymmetric-type two-electrode SC device and analysed its electrochemical features. This NiZrO 3 @GNP device exhibits the specific capacity of 47 C g -1 with capacitance retention of 70% after 2000 charge-discharge cycles. Further research on optimizing the synthesis process and exploring different device configurations could pave the way for even higher-performance supercapacitors in the future., Competing Interests: All authors declare that they have no conflicts to declare., (This journal is © The Royal Society of Chemistry.)