Supporting critical raw material circularity – upcycling graphite from waste LIBs to Zn–air batteries

Abstract

The use of Li-ion batteries (LIBs) is continuously growing, leading to a corresponding increase in the volume of end-of-life LIBs. Recycling of LIBs not only ensures the safe management of hazardous waste, but also minimizes the losses of valuable materials. While for some battery metals, such as Co, Ni, and Cu, industrial recovery processes have already been established, graphite is currently discarded as waste. This research introduces an innovative approach to create a bifunctional oxygen electrocatalyst by using the graphite waste fraction from hydrometallurgical recycling. Notably, we strategically utilized the residual metals left in the graphite fraction to achieve high electrocatalytic activity for both the ORR and OER under alkaline conditions. Our novel black mass-derived oxygen electrocatalyst was used as an air cathode catalyst in Zn–air batteries and demonstrated a high power density of 104 mW cm⁻² with outstanding long-term stability of 80 hours. This work unlocks new opportunities for repurposing overlooked graphite waste in energy conversion and storage applications.