Charge storage characteristics of mesoporous strontium titanate perovskite aqueous as well as flexible solid-state supercapacitor cell

Abstract

Perovskite oxides with high specific surface area can be a pertinent approach to boost up the performance for supercapacitors. In the present work, we demonstrate the outstanding charge storage properties of strontium titanate with cubic structure using sol-gel synthesis technique. Cubic structure of perovskite is undeniably useful for supercapacitors owing to its three-dimensional diffusion channels for oxygen anion diffusion. Strontium titanate electrode in ultrathin films displays high capacitance of 592 F g−1 at 5 mV s−1 due to its large specific surface area, mesoporous structure and excellent mass transfer rate of electrolytic ions. The symmetric supercapacitor cell in aqueous media demonstrates high specific capacitance (212.5 F g−1 at 0.63 A g−1), good capacitance retention (74.5% at 2.5 A g−1), excellent cycling stability (99% after 5000 cycles), high energy density (27.8 Wh kg−1) and good power density (1921 W kg−1). Upon charging for ∼ 60 s, the cell illustrates high energy density of 17.2 Wh kg−1 (at 1104 W kg−1). Flexible and solid-state symmetric cell exhibits good energy/power density (3.62 Wh kg−1 and 965 W kg−1) without any support or hybrid cell design. Therefore, all these electrochemical attributes signify the promising potential of STO in energy storage devices.