An array of batteries or supercapacitors. Batteries store energy electrochemically, but the charge and discharge process is slow and can degrade the chemical compounds inside the battery over time. As a result, batteries have a low power density and lose their ability to retain energy throughout their lifetime due to material damage. The supercapacitor uses a different storage mechanism. In the supercapacitor, energy is stored electrostatically on the surface of the material, and does not involve chemical reactions. Given their fundamental mechanism, supercapacitors can be charged quickly, leading to a very high power density, and do not lose their storage capabilities over time.