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Herein, we investigated CeVO4 nanostructures synthesized using a microwave-assisted hydrothermal method, focusing on their structural and electrochemical properties for potential supercapacitor applications. Notably, the selected synthesis method yielded a material that displays lattice spacing consistent with the (200) plane of the tetragonal CeVO4 structure, as confirmed by high-resolution transmission electron microscopy and corroborated by X-ray diffraction analysis. In addition, EDX spectroscopy demonstrated the high purity of the sample, with only Ce, V, and O elements presented, and XPS analysis revealed the chemical composition of the elements and oxidation states on the surface, with Ce3+, Ce4+, and V5+ identified. Following, cyclic voltammetry tests indicated pseudocapacitive behavior with well-defined redox peaks and good capacitive behavior and stability; then, galvanostatic charge–discharge profiles exhibited high specific capacitances at various current densities. After such analyses, an asymmetric supercapacitor was assembled using activated carbon as a cathode, and it demonstrated an excellent energy density value of 424.43 Wh kg−1 at a power density of 2783.11 W kg−1 (1 A g−1 in 2.0 M KOH). Thus, the comprehensive structural and electrochemical characterizations provided valuable insights into the material's potential for energy storage systems. [ABSTRACT FROM AUTHOR]

In the face of current energy and environmental challenges, electrochemical storage devices emerge as a promising alternative. Specifically, supercapacitors are highly valued for their exceptional ability to deliver rapid responses and exhibit high-power capabilities. Although rare-earth compounds have received less attention in the electrochemical storage field, the utilization of nanotechnology tools allows for precise manipulation of their shape and size, which opens new possibilities for developing novel configurations with improved properties, presenting previously unexplored applications. Herein, we set a new electrode material consisting of nanospheres of gadolinium vanadate (GdVO4) synthesized by microwave-assisted hydrothermal method, which was a crucial component in preparing nickel foam-based electrodes. The material was thoroughly characterized, revealing interesting properties for energy storage applications. The electrode delivered a high specific capacitance of 1203.75 F g−1 at 1 A g−1 and good cycling stability after 500 cycles. Then, an asymmetric supercapacitor was performed, reaching 80.63 F g−1 at 1 A g−1 and 130.2 Wh kg−1 of energy density when the power density was 2880.18 W kg−1. Thus, this study highlights the potential of GdVO4 as an electrode material in electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]