There are different types of laptop batteries like NiCad (nickel-cadmium), NiMH (Nickel-metal hydride) batteries and lithium-ion batteries.
Nickel-cadmium batteries have a low energy density, low discharge rate, and longer life. This is the oldest type and usually suffers memory effects, as a result of which they lose their capacity to recharge completely. However, they are known to offer great performance. They have proved to have a life of over 1000 lifecycles.
Nickel-metal hydride battery was designed as an alternative to Nickel-cadmium battery. Nickel-metal hydride battery offered a longer life as compared to Nickel-cadmium battery, however, it also suffered the memory effects just as Nickel-cadmium did.
The lithium-ion battery is the most preferred choice for laptop battery as it is lightweight and delivers better performance as compared to the other types of batteries. Lithium-ion batteries emerged as the solution for the most dreaded issue of memory effect. Lithium-ion batteries come with a rapid charging option. While Lithium-ion batteries are environment-friendly, while the other types of batteries harm the environment if not disposed of in the right manner.
It is very important to choose the right type of battery for your laptop as there have been cases where unapproved batteries have led to battery explosions.