Pokémon the Series: Sun & Moon Episode 3: Loading the Dex!
Episode 3 of 146 of Pokémon the Series: Sun & Moon, aired November 24, 2016, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Professor Kukui gives Ash an intelligent Rotom Pokédex that is capable of human speech. Ash goes to find and catch his first Pokémon in Alola, but he instead encounters Team Rocket, who are aided by a wild Mimikyu that despises Pikachu.