Simplify the following text for a Grade 9 native English-speaking person.
Original: The lithium ion Li + administered as any of several lithium salts has proved to be useful as a mood-stabilizing drug due to neurological effects of the ion in the human body . Lithium and its compounds have several industrial applications , including heat-resistant glass and ceramics , high strength-to-weight alloys used in aircraft , lithium batteries and lithium-ion batteries .
Simplified: Lithium ion batteries also have lithium in them , though not as an element .