An electrolyte conducts electricity, but it differs from an electrode because it comes in a liquid form. The term often comes up in articles about health and fitness, or used in the context of electronics and automotive technology.
An electrolyte is composed of ions. These are atoms that have either a positive or a negative electric charge. The concentration of ions to the total volume of the atom varies—a “dilute electrolyte” refers to one that has a minimal charge, while a “concentrated electrolyte” has a lot.
In automotive technology, an electrolyte is used to generate power. The liquid acts as a medium for ions to cross between the anode and cathode; simultaneously, it separates oxygen and hydrogen, which can react to each other. Some fuel cells (such as the proton exchange membrane cell) contains electrolytes that push the positive hydrogen ions from the anode to the cathode. This creates both water and electricity.
Electrolytes are also used in batteries, wherein they both conduct and store electricity. The type of material is important. Car batteries use sulfuric acid; small gadgets use lithium batteries; others use alkaline. The electrolyte material dictates what temperature they can be used in, plus the total amount of electricity it can manage.
Within the health and fitness arena, though, experts speak of “electrolyte balance.” They believe that the number of electrolytes in the body affect the heart, nervous system, and muscles. Sodium, potassium, magnesium, chloride and calcium are all electrolytes. The balance is maintained by the kidney and the hormones. Imbalances in sodium can cause hyper- and hypo-natremia, or excessive and insufficient levels of sodium; imbalances in potassium can cause hyper- and hypo-kalemia. Today, many sports drinks contain potassium and sodium in order to replenish any electrolytes lost during prolonged physical activity.