These anodes can be composed of several different materials including unencapsulated amorphous Ca(ClO)2 or nanolithia (Li2O/LiO2) encapsulated by Co3O4. The advantage of these amorphous structures is that they have more sites to accommodate Li ions than traditional crystalline electrodes. The number of Li ion sites is directly related to the electrode's capacity; therefore, the increased number of Li ion sites increases the battery's overall capacity. NASOCs are also self-contained without need to exchange oxygen with the outside (only lithium goes in and out), which makes them more stable and reliable. These cathodes also have a lower overpotential (0.25V compared to 1V) - potential difference between charging and discharging - which reduces heat emitted by the battery.