Nickel metal hydride (NiMH) has a terminal voltage of 1.2V. Is a type of rechargeable battery that combines nickel hydroxide (NiOOH) as the cathode and a hydrogen-absorbing alloy as the anode. There are several different combinations of alloys used in the anode to achieve different properties. Examples of substances that can be used in the alloy: manganese, cobalt, nickel, praseodymium, vanadium, titanium, lanthanum, cerium and others. NiMH batteries have a higher energy density than the older nickel-cadmium (NiCd) batteries, resulting in about 30-40% higher capacity. In general, NiMH cells work in a similar way to NiCd cells, which is why the same charger can often be used for both types of batteries. They are capable of about 500-1000 charge cycles depending on the manufacturer and conditions of use. High temperatures and deep discharging have a negative impact on life expectancy. Overcharging is harmful to NiMH as it is an exothermic technology. This means that heat is generated, especially during charging. Fast charging (1C) of NiMH requires careful monitoring of the charging process. NiMH is considered an environmentally friendly battery.