The Electrium Z (Japanese: デンキZElectric Z) is a type of Z-Crystal introduced in Pokémon Sun and Moon. It is the type-specific Z-Crystal associated with the Electric type and allows Pokémon to upgrade their Electric-type moves to Z-Moves.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot remove a Z-Crystal from a Pokémon.
In Trial and Tribulation!, Ash obtained another Electrium Z from Tapu Koko. It had swapped it with the Fightinium Z he was supposed to receive from Hala as a reward for completing his Melemele grand trial.