The energy-efficient desalination system produces fresh water without chemical additives and transforms leftover salts into useful materials. The United Nations estimates that 2.2 billion people lack safely managed drinking water, and communities from California to the Middle East rely on desalination plants to convert ocean water to fresh water. Common desalination techniques, such as reverse osmosis and thermal distillation, are energy-intensive, require pre- and post-water treatment, and leav...