The electrochemical measurements were done using two-electrode configurations for the symmetrical supercapacitors. The supercapacitors were prepared by sandwiching two electrodes with Whatman (GF/A) glassy fiber membrane which was wetted by 6.0 M aqueous KOH electrolyte. Aqueous Zn-ion capacitors (AZIC devices) were also assembled using the Swagelok type cells and the fabricated electrodes were used as cathodes, Zn metal foil (250 µm thick, Alfa Aeasar) as anode, 3.0 M aqueous ZnSO4 solution as the electrolyte and the glassy fiber membrane as a separator. The Swagelok cells were sealed at ambient conditions and the electrochemical measurements were also done under the same conditions. For symmetrical supercapacitors, electrochemical measurements were carried out in a voltage window of 0-0.8 V. For AZICs, the electrochemical measurements were carried out in a voltage window of 0-1.8 V using a multichannel Bio-Logic VMP3e potentiostat/galvanostat system. A LANDT-CT3002A batterycycler instrument was used for the galvanostatic charge-discharge (GCD) measurements.