Superionic ice (or superionic water) is a possible state (phase) of water under high temperature and pressure in which the molecules divide into atoms, the oxygen crystallizes, and the protons (hydrogen nuclei) remain free and can shift to move charge when the material is conducting electricity.
The phase has been theorized and experiments have produced some evidence of its existence. It is called an ice because it is theorized to be solid. It is thought that ice giants, such as Uranus and Neptune, might have the internal conditions to produce and maintain it. It might constitute part of such a planet's dynamo.