CO2 treatment enables non-hazardous, reliable, and efficacious recovery of spent Li(Ni0.5Co0.2Mn0.3)O2 cathodes

CO 2 treatment enables to recover low-valent metal oxides from spent Li(Ni 0.5 Co 0.2 Mn 0.3 )O 2 cathodes, which not only avoids the generation of explosive gases (H 2 ) during the acid leaching, but also allows Li extraction by simple water leaching.