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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.)