Self-assembly of graphene-based planar micro-supercapacitor with selective laser etching-induced superhydrophobic/superhydrophilic pattern

Abstract

Facile production of graphene-based in-plane interdigital electrode is critical for microscale supercapacitors but remains a great challenge (time consuming, expensive equipment needed, etc). The preparation of fine interdigital electrode planar micro-supercapacitors (MSCs) by selective laser etching of ceramic substrate is proposed, which provides an alternative method for rapid fabrication of planar MSCs. The formation of self-assembled electrode of graphene ink via the laser etching-induced heterogeneous surface wettability was firstly investigated, and then an all-solid-state MSCs microdevice was obtained by adding a polyvinyl alcohol–sulfuric acid gel electrolyte to the interdigital electrode region. The results of cyclic voltammetry test showed that the micro-supercapacitor device could offer an area capacitance of 5.5 mF cm−2 at a potential scan rate of 5 mV s−1 and the capacitance retention of 88.5% after 4500 cycles.