Augmented electrochemical properties of manganese oxide nanorods on low energy nitrogen ion irradiation

Abstract

For the development of versatile and high-performance storage devices, nanorods-based supercapacitors hold great promise due to their high energy density per unit volume and their resilience in the face of high mechanical stress. In this study, we demonstrated how to increase charge storage capacity by using an ion beam to join manganese oxide nanorods on a massive scale, thereby creating surface defects. Hydrothermally synthesized Mn3O4 nanorods were spin-coated on a silicon wafer and subjected to low energy (5 keV) N+ ion-beam at varying ion fluences before undergoing extensive electrochemical characterizations to verify their charge storage performance. At a mass normalized current of 10 A/g, the areal capacitance for pristine and irradiated Mn3O4 nanorods is 45 mF/cm2 and 132 mF/cm2. Hence, irradiated Mn3O4 nanorods were found to have better charge storage performance than their untreated counterparts. Insights into the improved charge-storage performance of irradiated nanorods are made clear by the detailed experimental findings. The irradiated sample further retains 90% of its initial capacitance for more than 5000 cycles of measurements. The enhanced areal capacitance performance after irradiation is due to the oxygen vacancy supported by TRI3DYN simulations. The high charge storage performance of the irradiated samples can be attributed to several factors, including the induced oxygen vacancy and improved surface area. This research adds to the growing body of evidence that ion beam irradiation can be used to fine-tune the supercapacitor electrode's surface area, conductivity, and storage capacity.