All mobile phones -- & most personal electronics and electrical vehicles -- use lithium-ion (li-ion) rechargeable batteries. It's a hardcore slog to develop batteries that go longer, because battery technology hasn't evolved in decades. Instead, much of the recent improvement in battery lifestyle has result from power-saving features included in devices and from making the program that manages charging and discharging more efficiently, which means you sip power rather than guzzle it.
Unfortunately for cell phones, the focus on extending battery life is normally on cars, satellites as well as your home's power system, areas where professional batteries have to function far further than the two or 3 years we expect from our mobile devices.
Another force performing against our phones is definitely their battery size. In comparison to an electric car battery, a phone's power source is minute. For example, the Tesla 3's rechargeable battery includes a battery potential over 4,000 moments higher than the iPhone 11 Pro Max.
The math gets just a little complex because phone batteries are measured in milliampere-time, while electric vehicle batteries are measured in watt-hours. But it's possible to pull equivalents. For instance, the Pixel 4 includes a 2,800-mAh battery (or 10.6 Wh), and the iPhone 11 Pro Max reportedly comes with a 3,969-mAh battery (15.04 Wh). Meanwhile, the Chevy Volt uses an 18,400-Wh battery pack and a midrange Tesla Model 3 flaunts a 62,000-Wh battery.