NiCd (Nickel-Cadmium) battery is a type of rechargeable battery based on a chemical composition involving nickel and cadmium oxide. NiCd batteries are used in various applications, such as consumer electronics, portable electronic devices, power tools, and emergency lighting.

Advantages of NiCd batteries:
+ Strong performance: They work well even at low temperatures and under high discharge currents, making them suitable for high-current applications like power tools.
+ Fast charging: They can charge faster than many other rechargeable battery types, reaching full capacity in a shorter time.
+ Durability: With proper care, they can last long and withstand hundreds of charge-discharge cycles.
+ Low self-discharge: Their low self-discharge rate reduces energy loss during storage.

Disadvantages of NiCd batteries:
+ Memory effect: Capacity decreases if they are recharged repeatedly without being fully discharged.
+ Not environmentally friendly: Cadmium is a toxic heavy metal, so recycling and disposal must be managed carefully.
+ Lower energy density: They store less energy compared to modern chemistries like NiMH or Li-ion.

While NiCd batteries were widely used in the past, their popularity has declined with the rise of more eco-friendly NiMH and lithium-ion alternatives. Still, NiCd may be chosen for applications requiring high current and reliable operation in low-temperature environments.

From my own perspective, NiCd is an “old but tough” technology. You can still find them in older cordless drills or emergency lighting systems. They’re heavier and less efficient than today’s Li-ion packs, but they taught engineers a lot about rechargeable cells. For students, it’s a perfect example to understand the trade-offs between chemistry, performance, and environmental impact.