nickel-cadmium

Nickel-cadmium describes a type of rechargeable battery that uses nickel oxide hydroxide and metallic cadmium as electrodes.

These batteries, often abbreviated NiCd or NiCad, were once standard in portable electronics, power tools, and emergency lighting before being largely superseded by lithium-ion technology.

The old cordless phone still runs on nickel-cadmium batteries.

They're known for being durable and tolerating deep discharge cycles, though cadmium's toxicity has led to restrictions on their use and disposal.