Lithium battery life is not calculated by the number of years, but by cycle.
The life of a lithium battery is "500 times", which means not the number of times of charging, but a period of charging and discharging.
Nowadays, mobile phones are all lithium batteries. Most of the lithium battery cycles are generally about 500 times. That is to say, from 0-100 to one cycle (cycle is 100 cycles), when the battery is 500 times, the battery is weak. The internal resistance becomes large, the internal chemical element activity decreases, and the rapid consumption stage is entered.
Everyone has had this experience. A very old mobile phone is turned off after a full call, so you can understand that the battery has run out.