The battery is not your typical alkaline or lithium-ion batteries commonly found in the market. But, if you know someone who is using a hearing aid, then, you have certainly encountered this battery. When one pours the salt and water inside the lamp’s case, the LED lamp emits light. Why? There is no alchemy here, just elementary science. The dissolved salt in water (which now exists in ionic form) closes the circuit and allows the flow of electrons and ions within the battery compartment. It’s quite similar to turning on a switch when you want to turn on the lights. Shortly, saltwater acts as the electrolyte to facilitate the current flow within the battery. Any electrolyte with enough ions will do the job. In fact, the best electrolytes for metal-air batteries are the “basic” solutions, such as potassium hydroxide and sodium hydroxide. With them, you can get more juice from your battery, but they’re more difficult to handle and dispose.