Studying supercapacitance properties of Mg3Si and Ti3Si as novel electrode materials: A first-principles study

In this research, the supercapacitor performance of two innovative and environmentally friendly materials, Mg${}_3$Si and Ti${}_3$Si, in bulk form are investigated using density functional theory (DFT). The mechanical and dynamic stability of these compounds are assessed through negative cohesive energy values and positive phonon density of states (DOS) modes. Furthermore, the electronic DOS analysis confirmed the metallic characteristics of these materials, highlighting their potential suitability as electrode materials. The partial electronic DOS at the Fermi level for Mg${}_3$Si was primarily contributed by the 3p orbitals of Si atoms, while for Ti${}_3$Si, the dominant contribution came from the 3d orbitals of Ti atoms. Furthermore, the highest surface quantum capacitance for Mg${}_3$Si was found along the xy direction, reaching 222.01 $\mu$F/cm${}^2$ at a positive bias of 2.54 V, while Ti${}_3$Si exhibited a value of 293.91 $\mu$F/cm${}^2$ at −0.59 V. These findings highlight the promising potential of these materials for supercapacitor applications.