What is the role of nickel oxide

What is the role of nickel oxide? There's a lot of people who don't know about nickel oxide, and here's the introduction to it:

The nickel oxide (Ⅱ) is a kind of common inorganic compounds, is bivalent nickel oxide, chemical formula for NiO, green powder, widely used in life, is also used for preparing high purity (> 99.98% nickel). This product is harmful to human health, the need to take care of the protection when contacting, the risk that the human body may have carcinogenic to sensitization.

It is used as an enamel with a mixture of additives and colorants, ceramics and glass. It is used in the production of magnetic materials to produce nickel-zinc ferrite, as well as to make nickel salt raw materials, nickel catalysts and applications in metallurgical and imaging tubes. It is used as electronic component material, catalyst, enamel coating and battery material.