Used in electroplating to produce wear-resistant and decorative cobalt coatings on metals. Serves as a precursor in the synthesis of other cobalt compounds and catalysts. Employed in rechargeable battery materials, especially in lithium-ion battery cathodes. Acts as a drying agent in paints and varnishes. Utilized in animal feed as a source of essential cobalt for ruminants. Applied in pigment production for ceramics and glass to achieve blue hues. Used in nutrient solutions for hydroponics and agriculture to supply trace cobalt. Also functions as a humidity indicator in silica gel due to color change with hydration state.