Ultrahigh volumetric performance of HRGO/MnO$_{\mathrm{2}}$ hybrid all solid state flexible supercapacitors

The development of flexible energy storage devices with high energy and high power densities is critical to the emergence of wearable electronics technologies. All solid-state flexible supercapacitors, a subset of these energy storage devices, are believed to be a key solution in powering fast, flexible mobile devices. Herein, we report an easy and low cost method to fabricate bendable holey reduced graphene oxide (HRGO)/manganese oxide (MnO$_{\mathrm{2}})$ electrodes using electrophoretic deposition. Cross sectional analysis of the layers using scanning electron microscopy (SEM) showed a layer-by-layer deposition. The obtained HRGO/MnO$_{\mathrm{2}}$ supercapacitor exhibited excellent electrochemical capacitive performance within a LiClO$_{\mathrm{4\thinspace }}$gel electrolyte, with a volumetric capacitance ranging between of 608.15F/cm$^{\mathrm{3}}$ and 233.95F/cm$^{\mathrm{3}}$ for electrodes masses between 0.2mg and 2.2mg. Additionally, the assembled supercapacitors exhibited an ultrahigh volumetric energy density of 54.06Wh L$^{\mathrm{-1}}$, and a power density of 9221.82 W L$^{\mathrm{-1}}$ which is the highest value so far reported for flexible supercapacitors.