Résumé
The role of defects in pseudocapacitive electrode materials has been poorly investigated due to the poor control of their introduction in a pure phase material. Chemical defects are difficult to monitor although it seems they have an obvious influence on the electrochemical properties of the pristine material. The controlled introduction of defects should provide a more rational approach to understand their role in charge storage mechanisms. This study investigates the impact of swift heavy ions irradiation on the electrochemical properties of pseudocapacitive vanadium nitride (VN) thin films, a promising material for micro-supercapacitor electrodes. VN films were irradiated with 129 Xe 19+ ions at an energy of 70.95 MeV and a fluences up to 10 14 ions⋅cm -2 . The effects of irradiation were compared to those observed in a previous study using lower-energy As + ions (20-150 keV) [1]. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectrons spectroscopy (XPS) analyses revealed significant structural changes in the irradiated films, including densification, amorphization and oxidation of VN film surface. The electrochemical performance of the irradiated films was evaluated using cyclic voltammetry. While capacitance was reduced at low scan rates, a notable improvement was observed at high scan rates, which is attributed to the increase in electrical conductivity resulting from irradiation. This study deepens our understanding of the effects of high-energy ion irradiation on electrode materials and highlights the potential of this technique as a tool for guiding the development of more efficient energy storage devices.