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.