With
the growing popularity of electronic devices and electric
vehicles, the number of spent lithium-ion batteries (LIBs) is increasing
dramatically. It is a promising and sustainable strategy to recycle
transition metal resources from cathodes of spent LIBs to prepare
functional materials for energy storage and conversion systems. This
review summarizes the recycling and upcycling of cathode materials
from spent LIBs, especially the upcycling, an alternative route to
direct regeneration. Multicomponent transition metal-based materials
are reported to be promising effective catalysts with the merits of
good electrochemical reactivity and excellent stability. The regeneration
of metal-based materials from spent cathodes for catalysts are summarized,
with an emphasis on oxygen evolution reaction (OER) catalysts for
water-splitting and oxygen reduction reaction (ORR)/OER bifunctional
catalysts for Zn–air batteries. Subsequently, we review in
detail the upcycling of valuable components from spent cathodes to
prepare electrode materials for supercapacitors. Finally, it concludes
with challenges and an outlook to ensure long-term sustainability
of battery industry.