This illustration shows the inner workings of a lithium-ion battery.
When delivering energy to a device, the lithium ion moves from the anode to the cathode. The ion moves in reverse when recharging.
Compared to other rechargeable batteries, lithium-ion batteries can store more energy in smaller, lighter packages. This unsurpassed energy-to-weight ratio make them the battery of choice for consumer electronics like cell phones and laptops, but also a great fit for electrified vehicles.
Illustration courtesy Argonne National Laboratory.