A high-performance three-dimensional micro supercapacitor based on ripple-like ruthenium oxide-carbon nanotube composite films

A micro-supercapacitor with a three-dimensional configuration has been fabricated using an inductively coupled plasma etching technique. A ruthenium oxide-carbon nanotube (CNT) composite with a ripple-like morphology is successfully synthesized using a cathodic deposition technique while using silica-based three-dimensional microstructures as a template. The desired network of carbon nanotubes in the composite facilitates electrolyte penetration and proton exchange/diffusion. A single three dimensional microelectrode is studied using cyclic voltammetry, and a specific capacitance of 272 mF.cm(-2) is observed at 5 mV s(-1) in a neutral Na2SO4 solution. The accelerated cycle life is tested at 80 mV s(-1), and a satisfactory cyclability is observed. When placed on a chip, the symmetric cell exhibits good supercapacitor properties, the specific capacitance up to 37.23 mF cm(-2) and specific power density up to 19.04 mW cm(-2) were obtained at 50 mA cm(-2). (C) 2014 Elsevier Ltd. All rights reserved.