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How do nickel-cadmium batteries compare with nickel-metal hydride batteries?
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Cutaway view of an alkaline–manganese dioxide power cell.
Nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries are both alkaline storage systems, but they differ significantly in performance and environmental impact.
Comparison of NiCd and NiMH Batteries
- Capacity: Nickel-metal hydride batteries are increasingly replacing nickel-cadmium batteries in many applications because they offer higher capacity per unit volume.1
- Environmental Impact: NiMH batteries are often preferred because they do not contain toxic cadmium, which is a key component of NiCd systems.1
- Performance Characteristics:
- NiCd: These batteries are known for delivering exceptionally high currents and are highly tolerant of abuse, such as overcharging or overdischarging. However, they are relatively heavy, have limited energy density, and can suffer from a "memory effect" if not fully discharged before recharging.1
- NiMH: These batteries utilize alloys, such as lanthanum-nickel, to reversibly store hydrogen as an active anode material. They are widely used in electric and hybrid-electric vehicles.1
While NiCd batteries remain useful for specialized tasks requiring high reliability, low temperatures, and high current—such as starting aircraft engines—NiMH batteries provide a more modern, higher-capacity alternative for general portable electronics.1