Disclosed is an ultracapacitor having electrodes containing mineral microtubules, an electrolyte between the electrodes, and a separator in the electrolyte to provide electrical insulation between the electrodes, while allowing ion flow within the electrolyte. The electrodes may be formed from a paste containing microtubules, a conductive polymer containing mineral microtubules, or an aerogel containing the mineral microtubules. The mineral microtubules may be filled with carbon, a pseudocapacitance material, or a magnetoresistive material. The mineral microtubules may also be coated with a photoconductive material.