Energy transfers through a lot of different things. Here are some of the ways:
Electrical energy- comes from the outlet and passes through the battery charger into the battery. The outlet decreases in electrical energy, the battery increases in stored chemical energy.
Radiation energy- comes from the sun and passes to the plant. The sun decreases in nlight or radiation from the air, and the plant increases in chemical energy from carbon stores.
My favorite energy transfer is radiation because the sun gives energy to all living things and that is very important.