What are liquid electrolyte batteries?

Liquid electrolyte batteries have been used for many years and are currently the most commonly used batteries, e.g. lithium ion batteries (LIB) in mobile phones. In liquid batteries, the electrolytes are present in dissolved form, but the electrodes are made of a solid material. The liquid electrolytes are usually highly flammable, which is often seen as a disadvantage. Therefore, solid-state batteries are currently being developed in which the electrolytes are in solid form.