Nanorods to hexagonal nanosheets of CuO-doped manganese oxide nanostructures for higher electrochemical supercapacitor performance

A Novel Synthesized 1D Nanobelt-like Cobalt Phosphate Electrode Material for Excellent Supercapacitor Applications

In the present report, we synthesized highly porous 1D nanobelt-like cobalt phosphate (Co₂P₂O₇) materials using a hydrothermal method for supercapacitor (SC) applications. The physicochemical and electrochemical properties of the synthesized 1D nanobelt-like Co₂P₂O₇ were investigated using X-ray diffraction (XRD), X-ray photoelectron (XPS) spectroscopy, and scanning electron microscopy (SEM). The surface morphology results indicated that the deposition temperatures affected the growth of the 1D nanobelts. The SEM revealed a significant change in morphological results of Co₂P₂O₇ material prepared at 150 °C deposition temperature. The 1D Co₂P₂O₇ nanobelt-like nanostructures provided higher electrochemical properties, because the resulting empty space promotes faster ion transfer and improves cycling stability. Moreover, the electrochemical performance indicates that the 1D nanobelt-like Co₂P₂O₇ electrode deposited at 150 °C deposition temperature shows the maximum specific capacitance (Cs). The Co₂P₂O₇ electrode prepared at a deposition temperature 150 °C provided maximum Cs of 1766 F g^-1 at a lower scan rate of 5 mV s^-1 in a 1 M KOH electrolyte. In addition, an asymmetric hybrid Co₂P₂O₇//AC supercapacitor device exhibited the highest Cs of 266 F g^-1, with an excellent energy density of 83.16 Wh kg^-1, and a power density of 9.35 kW kg^-1. Additionally, cycling stability results indicate that the 1D nanobelt-like Co₂P₂O₇ material is a better option for the electrochemical energy storage application.

Hydrothermal synthesis of CuO@MnO2 on nitrogen-doped multiwalled carbon nanotube composite electrodes for supercapacitor applications

Nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) have been used to fabricate nanostructured materials for various energy devices, such as supercapacitors, sensors, batteries, and electrocatalysts. Nitrogen-doped carbon-based electrodes have been widely used to improve supercapacitor applications via various chemical approaches. Based on previous studies, CuO@MnO₂ and CuO@MnO₂/N-MWCNT composites were synthesized using a sonication-supported hydrothermal reaction process to evaluate their supercapacitor properties. The structural and morphological properties of the synthesized composite materials were characterized via Raman spectroscopy, XRD, SEM, and SEM–EDX, and the morphological properties of the composite materials were confirmed by the nanostructured composite at the nanometer scale. The CuO@MnO₂ and CuO@MnO₂/N-MWCNT composite electrodes were fabricated in a three-electrode configuration, and electrochemical analysis was performed via CV, GCD, and EIS. The composite electrodes exhibited the specific capacitance of ~ 184 F g⁻¹ at 0.5 A g⁻¹ in the presence of a 5 M KOH electrolyte for the three-electrode supercapacitor application. Furthermore, it exhibited significantly improved specific capacitances and excellent cycling stability up to 5000 GCD cycles, with a 98.5% capacity retention.

Hexagonal nanostructured cobalt oxide @ nitrogen doped multiwalled carbon nanotubes/polypyyrole composite for supercapacitor and electrochemical glucose sensor

Hexagonal nanostructured cobalt oxide @ N-doped MWCNT /polypyyrole (Co₃O₄/PPy@N-MWCNT) composite was produced by an ultrasonication-mediated solvothermal method for electrochemical supercapacitor and glucose sensor applications. The structural and electrochemical properties of the Co₃O₄/PPy@N-MWCNT were confirmed by various spectroscopic and microscopic techniques. The as-prepared electrode showed an excellent capacitance of ∼872 F/g at 0.5 A/g with a capacitance retention of 96.8 %, even after 10,000 cycles. In addition, analysis of the sensing activity of the composite materials towards the glucose detection showed excellent electrochemical sensing performance that includes the glucose linear limit of (10 to 0.15) μm, detection sensitivity of 195.72 μA/cm²/mM, and lower detection value of S = 0.07327 μA/cm² @ R² = 0.99. The as-prepared composite material can be a promising candidate for the electrochemical supercapacitor and the efficient sensing of glucose.

Electrochemically Synthesized Nanoflowers to Nanosphere-Like NiCuSe2 Thin Films for Efficient Supercapacitor Application

Developing efficient electrochemically active nanostructures from Earth-abundant elements has gained significant interest in recent years. Among different transition metals, nickel and copper are abundant electrocatalysts for energy-storage applications. Nickel–copper selenide (NiCuSe2) nanostructures were prepared on a stainless-steel mesh with a cost-effective, simple, and versatile electrodeposition method for supercapacitor applications. The change effect in the bath concentration of nickel and copper altered the structural and electrochemical properties of NiCuSe2 electrode. X-ray diffraction (XRD) patterns confirmed the pure phase of ternary NiCuSe2 thin films with a cubic crystal structure. The surface morphology of NiCuSe2 was tuned by nickel and copper from spherical porous nanoflowers, nanoplates, nanocubes, and nanosphere-like nanostructures deposited on the stainless-steel mesh. The electrochemical performance of the electrodeposited NiCuSe2 was investigated in alkaline 1 M KOH electrolyte. The synergetic effect of bimetallic nickel and copper with the selenide electrode showed superior specific capacity of about 42.46 mAh g−1 at 10 mV s−1 along with reasonable cycling stability.