Direct laser writing of micro-supercapacitors on thick graphite oxide films and their electrochemical properties in different liquid inorganic electrolytes

In this article we demonstrate a simple approach to fabricate interdigitated in-plane electrodes for flexible micro-supercapacitors (MSCs). A nanosecond ultraviolet laser treatment is used to reduce and pattern the electrodes on thick graphite oxide (GO) freestanding films. These laser-treated regions obtained by direct writing provide the conducting channels for electrons in the capacitors. The electro-chemical performance of the MSCs was evaluated in the presence of two different electrolytes and they exhibit characteristics of nearly electrical double layer capacitors. The MSCs have areal capacitances as 2.40, 2.23 and 1.62 mu F/cm(2) for NaOH, Na2SO4 and KCI electrolytes respectively, for measurements performed at the scan rate of 50 mV/s. They retain similar to 93.1% of their initial capacitances after 3500 cycles (scan rate = 80 mV/s) in NaOH electrolyte. The proposed laser treatment approach enables facile and fast fabrication of flexible MSCs without the need for tedious processing methods such as photolithographic micro-patterning and deposition of porous carbon or metallic current collectors. (C) 2017 Elsevier Inc. All rights reserved.