Low-carbon upcycling of spent anode graphite: Integrating graphene and dislocations for sustainable lithium/potassium storage

Nowadays, the recycling and sustainable energy storage techniques of spent rechargeable batteries have garnered tremendous passion and scrutiny on account of the escalating environmental crisis and energy shortage. This study presents a facile and green method for upcycling graphite from spent lithium-ion batteries. Unlike conventional high-temperature calcination approaches, our technique leverages low-temperature annealing at 350 °C in air to treat graphite from spent anodes after diluted nitric acid (5 mol/L) leaching. This craft is characterized by its simplicity, safety, and cost-effectiveness. Experimental results reveal that the upcycled graphite stimulated both lithium and potassium storage. Specifically, the upcycled graphite maintains the boosting capacity of 415.6 mAh/g after 180 cycles in lithium-ion cells. This stellar performance is attributed to the formation of graphene sheets, abundant dislocations, and the preservation of ample interlayer spacing. Our method substantially reduces energy consumption and environmental pollution. Future research will further explore the applications of upcycled graphite in other types of ion batteries and mitigate its environmental impacts.