Final answer:
Rechargeable batteries lose their recharging capacity over time due to the increased internal resistance and the inefficiency of chemical reactions within the battery from repeated charging and discharging cycles, leading to decreased terminal voltage and potential overheating.
Step-by-step explanation:
Rechargeable batteries, such as nickel-cadmium and lead-acid batteries, tend to lose their ability to recharge after being used over time. This deterioration in charging efficiency is primarily due to an increase in the internal resistance within the battery. As the battery ages, chemical reactions that store and release energy become less efficient, leading to a higher internal resistance. This resistance is a significant factor while charging the battery and contributes to the slower charging rates experienced as the battery becomes older. Furthermore, this increased internal resistance can cause terminal voltage to decrease and even lead to a battery overheating due to the power dissipated by the resistance. The chemical reactions involved in storing and releasing electrical energy in a battery become less reversible with use. Each charging cycle can gradually wear out the active materials within the battery cells, making it harder to restore the original electrical potential needed to power devices. Additionally, larger batteries that consist of cells connected in series suffer from a cumulative effect where the degradation in individual cells results in an overall decrease in battery potential, which falls below a useful threshold after many cycles.