Integrated room-temperature aqueous separation, purification, and regeneration of full-size commercial spent lithium-ion battery electrodes

This study investigates the aqueous separation, purification, regeneration, and electrochemical evaluation of cathode and anode materials recovered from commercial NCM523/graphite pouch cells cycled for 100–300 charge–discharge cycles and used after DMC rinsing without NaCl-solution discharge pretreatment. Under alkaline conditions (0.6–0.8 M NaOH) at ambient temperature, cathode active materials were spontaneously delaminated from Al current collectors without ultrasonication. Delamination occurred within a limited alkaline concentration range, where gas evolution accompanying Al dissolution may facilitate interfacial separation, although the delamination behavior was also influenced by alkaline conditions and alkali species. In contrast, immersion of cycled graphite anodes in water induced gas evolution associated with residual Li-containing species, promoting graphite detachment from Cu current collectors. Transition metals (Ni, Co, Mn, and Al) deposited on graphite during cycling were effectively removed by dilute H₂SO₄ treatment, and subsequent heat treatment restored electrochemical performance. The results demonstrate distinct aqueous separation behaviors for cathode and anode materials and suggest that preserving cycling-induced characteristics is important for understanding recycling-relevant phenomena in spent lithium-ion battery electrodes.