There have been many types of cell phone batteries over the past ten years. Recent cell phone manufacturers have switched to high-end Lithium-Ion technology for their cell phone batteries.
Mobile phones were powered by a Nickel-Cadmium battery that was "memory". This means that the battery would think it was empty if it reached 50% of its charge capacity. Then it would charge itself to that 50%.
Image Source: Google
Many people remember how quickly cell phone batteries died when they were charged with (Ni-Cad). To ensure the proper memory parameters, you should let your Nickel-Cadmium and Nickel-Metal Hydride batteries run to the end before charging.
The memory effect of Lithium-Ion batteries is negligible. You can charge your phone even if the battery is at 80%, or completely dead, without damaging the battery.
These batteries are also safe to use while charging. If the battery was charged while it was still in its original form, older cell phones would have suffered damage. With the newer batteries for mobile phones, this is no longer the case.
Another really great feature of Lithium batteries is their weight. We all remember the "brick" cell phones that were heavy. Today's cell phones are lighter than ever because of the new Lithium-Ion battery.
These batteries are lightweight and require very little space. This technology has allowed us to make technological breakthroughs such as the iPhone and iPod. Many hybrid vehicles use the same Lithium-Ion technology.