What type of battery was the earlier design for smartphone rechargeable batteries?

Smartphones initially relied on lithium-ion (Li-ion) batteries for their rechargeable power source. The popularity of Li-ion batteries can be attributed to several key advantages that make them well-suited for portable electronic devices like smartphones.

One of the main benefits of Li-ion batteries is their high energy density, meaning they can store much more energy in a smaller and lighter package compared to other battery types. This characteristic is essential for smartphones, where space and weight considerations are critical. Furthermore, Li-ion batteries have a lower self-discharge rate, allowing them to retain their charge for longer periods when not in use.

The efficiency and performance of Li-ion batteries, including their ability to support rapid charging and a longer lifespan compared to other rechargeable batteries, contributed to their widespread adoption in smartphone design from the early stages of mobile technology.

In contrast, other battery types like nickel-cadmium (Ni-Cd) and lead-acid batteries have significant limitations—such as memory effect, lower energy density, and heavier weight—that make them less practical for modern smartphones. Similarly, while lithium-polymer (Li-Po) batteries are also used in some smartphones, they are typically a later development, with Li-ion batteries being the earlier and more predominant choice in the initial