This means that the batteries can handle a great many more charging cycles without losing capacity. The new method also means that the batteries can easily be restored once they have begun to wear out, unlike other rechargeable batteries that must be melted down for recycling. Most rechargeable batteries are based on either lead, nickel-cadmium (NiCd) or various combinations with lithium. Batteries based on nickel-metal hydride (NiMH) with an aqueous electrolyte are both eco-friendly and safe. The NiMH battery is developed from the nickel-hydrogen battery (NiH2). It has long been known that (NiH2) batteries have a superior lifespan compared to other battery types.
This is why they are (for example) used in satellites in orbit in space, where the batteries must function for decades without servicing.