Lithium

Lithium is a material and an element added by various mods.

Vanilla
on the Minecraft Wiki

IndustrialCraft 2
Tiny Pile of Lithium Dust can be obtained by processing in a. Despite there being an item named, it is currently unobtainable, making Lithium useless without other mods installed.

Mekanism
Lithium does not have an ore or ingot form, and requires multiple machines to be made usable. Lithium dust is used for crafting all tiers of Induction Cell and Induction Provider, both major parts of the Induction Matrix multiblock, whilst Lithium (gaseous) is used to make Tritium. To obtain Lithium, you need to turn water into brine in a Thermal Evaporation Plant. After that, you need another Thermal Evaporation plant to turn the brine into liquid lithium. This liquid lithium must then be put into a Rotary Condensentrator to be turned into a gaseous form of lithium. To turn that into lithium dust, you need to feed the liquid lithium to a Chemical crystallizer with pressurized tubes.

NuclearCraft
Lithium is a naturally occurring element that spawns as Lithium Ore between Y=0 and Y=32. It is used to produce many various items and alloys, including and various Lithium Ion batteries. Its isotopes can be used with other light elements in various recipes.