“…However, the more consumption of LiBs means the more amount of scrap. In spent LiBs, the cobalt and lithium contents are 5-15 wt.% and 2-7 wt.% respectively, which are higher than those found in natural ores or even concentrated natural ores, and also have a potential hazard to the ecosystem and human health [5,6]. From the viewpoints of environmental preservation, recovery of major components or valuable resources, and provision of raw materials, the recycling of spent LiBs is highly desirable in either the present or the future [7][8][9].…”