Used in electroplating to deposit a protective or decorative layer of nickel on metals, enhancing corrosion resistance and surface hardness. Commonly employed in the production of batteries, especially nickel-cadmium and nickel-metal hydride types, due to its role in the redox chemistry of the cell. Serves as a catalyst precursor in industrial hydrogenation and petroleum refining processes. Utilized in the synthesis of other nickel compounds and as a mordant in dyeing textiles to improve color fastness. Also applied in metal surface treatment and as a nutrient source of nickel in some industrial fermentation processes.