Litium
Lithium is an old technology, but because of the instability of the lithium metal it was not possible to commercialize it until around 1970 for non-rechargeable (primary) lithium and around 1990 for rechargeable (secondary) lithium (lithium-ion) batteries. Lithium batteries must always be handled with care due to the high energy density, even more so when charging Li-ion batteries, however, with proper security precautions the high energy density of the lithium cells is welcomed.
