Why do Rechargable Batteries Lose Their Capacity to Held Energy?

[Faith No More]

Any battery issue is by definition a chemistry problem. In a healthy battery, ions flow freely between a cathode and an anode. Charging a battery forces ions from the cathode to the anode; using the battery reverses the flow.

Over time, this process wears out the cathode, which results in reduced capacity. A high-end lithium-polymer battery can lose about 20 percent of its capacity after 1000 charge cycles. Another way to think of this is to imagine that every time you recharge your laptop, you shave a few seconds off its maximum battery life. Erratic charging and heat speed up this degradatio

http://www.popularmechanics.com/technolo...e-6705747/

Google is your friend, you know.