Why do phone batteries discharge faster with time?

To understand why phone batteries discharge faster with time, we need to understand how the phone battery works.

In a phone battery, there are two components that are important, a negative electrode (called anode), a positive and electrode (called cathode).

When you charge your phone you are simply applying charge to the electrodes. There is conversion of electrical energy into chemical energy. Same thing happens when the phone discharges (when it is not charged), charge moves from one electrode to another.

Now, remember the second law of thermodynamics that says when energy is converted from one form to another a part of the energy is lost (wasted). The proportion of wasted energy to stored energy grows over time. The more you use a battery, the more energy gets wasted, and the sooner the battery will reach a point where it’s dead and can’t usefully be recharged.

This is the reason why battery discharge over time.

It is a proven fact that during certain times of the year that a phone battery is able to discharge faster. This can be attested to the fact that chemical reactions are the reason that phone batteries discharge faster. Cold weather means that the chemicals do not react as fast where during the warm weather months the chemicals react faster. This would mean that during the winter a cold battery will stay around longer but will not have much power to power the device and the discharge is faster. The opposite happens during the summer. Summer time sees very past power out of the phone battery. Over time, the same principle is in place. When a battery wears out over time it might charge up but it is going to discharge faster. Therefore, it is the weather and its effect on chemical reactions in the battery that causes a phone battery to discharge faster over the course of time.