NiCd batteries, or nickel-cadmium batteries, are a type of rechargeable battery that uses nickel oxide hydroxide and cadmium as electrodes. They are known for their ability to deliver high discharge rates and perform well in extreme temperatures. These batteries are commonly used in portable electronics, power tools, and emergency lighting. One notable feature of NiCd batteries is their memory effect, which can reduce their capacity if they are not fully discharged before recharging. Despite this, they are valued for their durability and long cycle life. However, environmental concerns regarding cadmium, a toxic heavy metal, have led to a decline in their use in favor of other battery technologies.