Phobium
a metallic alloy based on the ore chanlon, phobium was discovered for use in the creation of power cells many millennia before the Galactic Civil War. The ancient Jedi Knights sometimes used phobium-based power cells in their lightsabers. During the height of the Clone Wars, phobium was used in the construction of the power core of the Death Star. Much of the phobium mined during the construction of the second Death Star came from the planetoid Dor. Note that The Glove of Darth Vader claims that phobium was mined directly from the planet Gargon.