Nickel compounds have a variety of important functions and applications, mainly including the following aspects: Catalysts: Nickel compounds are widely used in catalysts, especially in petroleum refining, hydrogenation reactions and organic synthesis. For example, nickel catalysts can be used in hydrodesulfurization reactions to remove sulfur from petroleum products. Battery materials: Nickel is used to make nickel-metal hydride (NiMH) batteries and nickel-cadmium (NiCd) batteries. These batteries are widely used in portable electronic devices and electric vehicles because of their good charge and discharge performance and cycle life. Electroplating: Nickel compounds are often used in electroplating processes to provide a protective layer on the metal surface, enhancing corrosion resistance and aesthetics. Nickel electroplating is widely used in automobiles, home appliances and decorations. Catalytic cracking: In the petrochemical industry, nickel compounds are used as catalysts in catalytic cracking to promote the decomposition and conversion of complex organic molecules. Pigments and colorants: Certain nickel compounds can be used as pigments in ceramics, coatings and plastics to provide specific colors and luster. Electronic materials: Nickel compounds can be used to make electronic components such as capacitors and resistors because of their good conductivity and stability.