Like any lead-acid batteries, lead-acid scooter batteries come with flat plates of lead in an electrolyte. This lets it store charge and provide power to run different applications when needed.
This is fairly old technology. But it has evolved into different variations over the years. There are several types of lead-acid batteries. There are flooded and sealed lead-acid batteries.
Sealed lead-acid batteries are the best for any case. They are more expensive and generally offer better performance.