Ultra high capacitance values of Pt@RuO2 core-shell nanotubular electrodes for microsupercapacitor applications

► An array of Pt nanotubes is formed. ► Ruthenium dioxide is deposited in the interior and the exterior of the Pt nanotubes. ► The ruthenium dioxide utilization efficiency is 94.6%. ► The specific geometric capacitance reaches 320mF cm−2.