Towards Greener Recycling: Direct Repair of Cathode Materials in Spent Lithium-Ion Batteries

Abstract The explosive growth and widespread applications of lithium-ion batteries in energy storage, transportation and portable devices have raised significant concerns about the availability of raw materials. The quantity of spent lithium-ion batteries increases as more and more electronic devices depend on them, increasing the risk of environmental pollution. Recycling valuable metals in these used batteries is an efficient strategy to solve the shortage of raw materials and reduce environmental pollution risks. Pyrometallurgy, hydrometallurgy and direct repair have been extensively studied to achieve these goals. The latter is considered an ideal recycling method (for lithium-ion cathode materials) due to its low cost, energy consumption, short duration and environmental friendliness, and it is nondestructive towards the cathode material itself. However, the direct repair is still in its earlier development stages, and a series of challenges must be tackled to succeed in commerce. This work summarizes the process, its effect and the mechanism of different direct repair methods. Moreover, the energy consumption, greenhouse gas emissions, costs and benefits of different methods will be discussed from economic and environmental perspectives. Feasible strategies are also proposed to address existing challenges, providing an insightful overview of the direct reparation of spent lithium-ion cathode materials. Graphical Abstract