Room temperature fabrication of MnO₂-based printable and flexible microsupercapacitors

Abstract

Wearable electronics require reliable, light weight, efficient, easy-to-integrate and mechanically compliant power sources. The increasing energy demand in emerging wearable and portable electronic devices has resulted in emergence of a new research area, namely, microsupercapacitors (MSCs), which are compact, high energy density, miniaturized supercapacitor units. In this study, $\varepsilon{-}$ Mn02 nanoflowers (NFs) have been synthesized by chemical reduction of KMn04. A printable ink formulated with these nanoflowers and deposited onto Sn-doped indium oxide (ITO) coated PET (polyethylene terephthalate) exhibits a specific capacitance of 384 F/g under the 3-electrode measurement setup. Next, the ultrathin, flexible, lightweight symmetric MSCs fabricated with E-Mn02 nanoflowers has demonstrated specific gravimetric capacitance of 111.5 F/g at a voltage scan rate of 2 m V/s with a potential window of 2 V. The gravimetric energy density and power density of these MSCs have been estimated as 38.4 W.h/kg and 10 kW/kg at specific current of 0.5 A/g and 10 A/g, respectively. In addition, the areal capacitance value has been estimated as 3.9 mF/cm ² .