Supercapacitor devices based on multiphase MgTiO3 perovskites doped with Mn2+ ions

Abstract

Recently, perovskites have become a hotspot for researchers attempting to exploit metal and oxygen vacancies in structures of the form MTiO₃, facilitating the convenient electron/hole migration, thus displaying interesting properties. Magnesium Titanate (MgTiO₃) is a prominent part of the perovskite class, exhibiting remarkable electrical, thermal, and chemical properties. Undoped and Mn-doped MgTiO₃ samples were obtained using a solid-state reaction starting from previously synthesized MgO and TiO₂ powders, which were separately doped with different Mn ion concentrations. The resulting multiphase materials with a major MgTiO₃ phase were thoroughly morpho-structurally analyzed employing XRD, STEM, Raman, PL, XPS, and EPR spectroscopy. The electrochemical results indicate that they show superior performance when used as electrode materials for supercapacitor application due to the high defect concentration as shown in EPR and PL spectroscopy and the ferroelectric behavior observed in XPS and XRD. When used in symmetric and asymmetric supercapacitor devices, they show promising results, with specific capacity values reaching up to 109 F/g for the symmetric and 609 F/g for the asymmetric devices, while energy and power density values reached 84.7 Wh/kg and 90.8 kW/kg respectively, proving a great potential in the energy storage field.