Vanadium-doped magnesium oxide nanoparticles as electrodes in supercapacitor devices

Vanadium (V)-doped MgO nanoparticles were used as electrode materials in all-in-one solid-state supercapacitor applications. The prepared samples’ structural and morphological properties were thoroughly analyzed using XRD, Raman spectroscopy, TEM, PL, and BET. EPR spectroscopy was employed to analyze the paramagnetic centers induced in the host material and showed that all V-doped samples displayed a V4+ characteristic EPR signal. The electrochemical analysis of the assembled symmetric supercapacitors was done using cyclic voltammetry, galvanostatic cycling with potential limitation technique, and potentiostatic electrochemical impedance spectroscopy. The results reveal that the novel V-doped MgO material displayed excellent capacitance performance between 0 and 1 V, delivering a specific capacitance of 50 F/g at a 10 mV/s scan rate. It also exhibits a maximum energy density of 4.17 Wh/kg, comparable to values obtained from other symmetric supercapacitor configurations. When a booster material like carbon black was added, the specific capacitance value increased dramatically to 1200 F/g, values that were never reported before in the literature for MgO-based materials

All-in-one supercapacitor devices based on nanosized Mn4+-doped WO3

In this study, nanosized Mn-doped WO3-based materials were used as electrode materials for high-performance supercapacitor devices. Various Mn concentrations (0.5, 1, and 1.5%) were used to change the defect structure of WO3, which improved the material's electrical properties. A thorough morpho-structural and defect structure analysis of the undoped and doped WO3 was performed through various characterization techniques, among which EPR and PL spectroscopy gave insight into the effect that Mn-doping caused on the defect structure and optical properties of WO3. The presence of Mn4+ ions and a high concentration of oxygen vacancies was observed, strongly influencing the electrode material when used in symmetric supercapacitors, where the electrochemical performance was tested. The symmetric supercapacitors were designed without booster materials (like carbon black) and showed increased specific capacitance (115 F/g) and energy density (16 Wh/Kg) values

Nitrogen-Doped WO₃ Nanoparticles as Electrode Materials in All-in-One Supercapacitor Devices

The effect of the annealing temperature on 1% nitrogen-doped WO3 materials was studied, which were then used as electrode materials for high-performance supercapacitor (SC) devices. The supercapacitive performance of the proposed materials was strongly influenced by the doping element and the annealing temperature by directly changing the defect structure of the host material. The 1% N-doped WO3 materials annealed at different temperatures were thoroughly characterized through various characterization techniques, including electron paramagnetic resonance and photoluminescence spectroscopy, giving insight into the effect of N-doping on the defect structure and optical properties of WO3. When the WO3:N materials were used as electrode material in symmetric SCs, the doping element and the annealing temperature improved the electrochemical performance. No booster materials (such as carbon black) were used in the symmetric SC designs, showing increased specific capacitance (102 F/g) and energy density (14.6 W h/kg) values