A substance that dissociates fully or partially into ions when dissolved in a solvent, producing a solution that conducts electricity.
In a lead-acid battery, the electrolyte is a solution of sulfuric acid.
A strong electrolyte is a solute that completely dissociates into ions in solution. Solutions of strong electrolytes conduct electricity. Most soluble ionic compounds are strong electrolytes. Strong acids are strong electrolytes.
A weak electrolyte is a solute that incompletely dissociates into ions in solution. For example, acetic acid partially dissociates into acetate ions and hydrogen ions, so that an acetic acid solution contains both molecules and ions. A solution of a weak electrolyte can conduct electricity, but usually not as well as a strong electrolyte because there are fewer ions to carry the charge from one electrode to the other.
Medium in a battery in which ions move to create an electrochemical reaction. Either water or non-aqueous solution is used as solvent. The latter is called non-aqueous electrolyte solution, either organic or inorganic.
An electrolyte made motionless by use of a gel additive or AGM separator.