Spare (uninstalled) lithium ion and lithium metal batteries, including power banks and cell phone battery charging cases, must be carried in carry-on baggage only. With airline approval, passengers may also carry up to two spare larger lithium ion batteries (101–160 Wh) or lithium metal batteries (2-8 grams).

Li-ion batteries use chargers equipped with a safety feature that monitors the charging process and cuts the power if a problem arises. NiMH batteries are much harder to charge than Li-ion batteries because they don't have a "float charge" voltage like lithium-ion chemistry and must be charged using a constant current.

No. Energizer lithium batteries are not designed to be recharged.

Most lithium-ion batteries cost $10 to $20,000, depending on the device it powers. An electric vehicle battery is the most expensive, typically costing $4,760 to $19,200. Next is solar batteries, which usually cost $6,800 to $10,700.