High-performance double ion-buffering reservoirs of asymmetric supercapacitors based on flower-like Co3O4-G>N-PEGm microspheres and 3D rGO-CNT>N-PEGm aerogels

Design of Hollow Porous P-NiCo2O4@Co3O4 Nanoarray and Its Alkaline Aqueous Zinc-Ion Battery Performance

Alkaline aqueous zinc-ion batteries possess a wider potential window than those in mildly acidic systems; they can achieve high energy density and are expected to become the next generation of energy storage devices. In this paper, a hollow porous P-NiCo2O4@Co3O4 nanoarray is obtained by ion etching and the calcination and phosphating of ZiF-67, which is directly grown on foam nickel substrate, as a precursor. It exhibits excellent performance as a cathode material for alkaline aqueous zinc-ion batteries. A high discharge specific capacity of 225.3 mAh g-1 is obtained at 1 A g-1 current density, and it remains 81.9% when the current density is increased to 10 A g-1. After one thousand cycles of charging and discharging at 3 A g-1 current density, the capacity retention rate is 88.8%. Even at an excellent power density of 25.5 kW kg-1, it maintains a high energy density of 304.5 Wh kg-1. It is a vital, promising high-power energy storage device for large-scale applications.

Optimization and analytical behavior of a morphine electrochemical sensor in environmental and biological samples based on graphite rod electrode using graphene/Co3O4 nanocomposite

In this research, a new sensor based on graphene/Co₃O₄ (Gr/Co₃O₄) nanocomposite was employed for electrochemically determination of morphine (MOR). The modifier was synthesized with a simple hydrothermal technique and well characterized using X-ray difraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) tools. The modified graphite rod electrode (GRE) was revealed a high electrochemical catalytic activity for the MOR oxidation and employed for the electroanalysis of trace MOR concentration by means of differential pulse voltammetry (DPV) technique. At the optimum experimental factors, the resulting sensor offered a good response for MOR in the concentration range of 0.5-100.0 μM with a detection limit of 80 nM. In addition, the modified electrode demonstrated an acceptable selectivity, stability and reproducibility. This assay was also provided a valid platform for the detection of MOR in environmental and biological samples with acceptable recoveries and RSD in the range of 97.2-102.8% and 1.7-3.4%, respectively. Taking to the simplicity, low cost and short analysis time, this approach is suggested for clinical, environmental and forensic testing of MOR.

A Simple Route to Produce Highly Efficient Porous Carbons Recycled from Tea Waste for High-Performance Symmetric Supercapacitor Electrodes

High-performance porous carbons derived from tea waste were prepared by hydrothermal treatment, combined together with KOH activation. The heat-treatment-processed materials possess an abundant hierarchical structure, with a large specific surface of 2235 m² g⁻¹ and wetting-complemental hydrophilicity for electrolytes. In a two-electrode system, the porous carbon electrodes’ built-in supercapacitor exhibited a high specific capacitance of 256 F g⁻¹ at 0.05 A g⁻¹, an excellent capacitance retention of 95.4% after 10,000 cycles, and a low leakage current of 0.014 mA. In our work, the collective results present that the precursor crafted from the tea waste can be a promising strategy to prepare valuable electrodes for high-performance supercapacitors, which offers a practical strategy to recycle biowastes into manufactured materials in energy storage applications.

High Electrochemical Performance of Bi2WO6/Carbon Nano-Onion Composites as Electrode Materials for Pseudocapacitors

Bi₂WO₆/CNO (CNO, carbon nano-onion) composites are synthesized via a facile low-cost hydrothermal method and are used pseudocapacitor electrode material. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption techniques, and X-ray photoelectron spectroscopy (XPS) measurements are used to characterize the synthesized composite powders. The electrochemical performances of the composite electrodes are studied by cycle voltammetry, charge-discharge, and electrochemical impedance spectroscopy. The results indicate that the specific capacitance of the Bi₂WO₆/CNO composite materials reaches up to 640.2 F/g at a current density of 3 mA/cm² and higher than that of pristine Bi₂WO₆, 359.1 F/g. The capability of the prepared pseudocapacitor remains 90.15% after 1,000 cycles of charge-discharge cycling measurement. The cell performance and stability can be enhanced by further optimization and modification of the composition and microstructure of the electrode of the cell.

Recent Advance in Co3O4 and Co3O4-Containing Electrode Materials for High-Performance Supercapacitors

Among the popular electrochemical energy storage devices, supercapacitors (SCs) have attracted much attention due to their long cycle life, fast charge and discharge, safety, and reliability. Transition metal oxides are one of the most widely used electrode materials in SCs because of the high specific capacitance. Among various transition metal oxides, Co3O4 and related composites are widely reported in SCs electrodes. In this review, we introduce the synthetic methods of Co3O4, including the hydrothermal/solvothermal method, sol-gel method, thermal decomposition, chemical precipitation, electrodeposition, chemical bath deposition, and the template method. The recent progress of Co3O4-containing electrode materials is summarized in detail, involving Co3O4/carbon, Co3O4/conducting polymer, and Co3O4/metal compound composites. Finally, the current challenges and outlook of Co3O4 and Co3O4-containing composites are put forward.