fig6

Figure 6. (A) Schematic illustration of the CoFe/C catalyst cathode synthesis from spent LIBs to optimize Zn-air batteries. Quoted with permission from Jiao et al.^[60]; (B) The route of recycling spent LIBs to prepare Co@NG catalyst. Quoted with permission from Serbara Bejigo et al.^[61]. LIBs: Lithium-ion batteries.