Simplify the following text for a Grade 9 native English-speaking person.
Original: In January 2008 , the United States Department of Transportation ruled that passengers on board commercial aircraft could carry lithium batteries in their checked baggage if the batteries are installed in a device . Types of batteries affected by this rule are those containing lithium , including Li-ion , lithium polymer , and lithium cobalt oxide chemistries .
Simplified: They are different from lithium batteries though .