Rechargeable Batteries A rechargeable battery is a group of two or more secondary cells where the release of energy is reversible. Whilst having higher up-front costs (versus disposables), they can be discharged / recharged many times. Makers of NiMH rechargeables claim a lifespan up to 3000 charge cycles. Common chemistries are nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer).