Methods of increasing an energy density of an energy storage device involve increasing the capacitance of the energy storage device by depositing a material into a porous structure of the energy storage device using an atomic layer deposition process, by performing a procedure designed to increase a distance to which an electrolyte penetrates within channels of the porous structure, or by placing a dielectric material into the porous structure. Another method involves annealing the energy storage device in order to cause an electrically conductive substance to diffuse to a surface of the structure and form an electrically conductive layer thereon. Another method of increasing energy density involves increasing the breakdown voltage and another method involves forming a pseudocapacitor. A method of increasing an achievable power output of an energy storage device involves depositing an electrically conductive material into the porous structure.