Ni, or nickel, is a chemical element with the symbol Ni and atomic number 28. It is a silvery-white metal known for its strength, corrosion resistance, and ability to withstand high temperatures. Nickel is commonly used in the production of stainless steel and other alloys, making it essential in various industries, including construction and manufacturing. In addition to its industrial applications, Ni is also used in batteries, particularly in rechargeable types like nickel-cadmium and nickel-metal hydride. This versatility makes nickel an important element in modern technology, contributing to the development of electric vehicles and portable electronic devices.