While hydrometallurgy is the primary technology for recycling spent lithium-ion batteries due to various advantages, it still involves substantial consumption of chemical reagents and poses challenges in wastewater emission. Herein, we report the realization of cathode recycling under lean-leachate conditions by dynamically stabilizing hole-mediated diffusion kinetics, which is enabled by synchronizing the extraction step during the leaching stage, thus continuously removing the dissolved ions out of the leachate. Theoretical molecular dynamics simulations predict that preventing the accumulation of the dissolved ions is efficient for keeping the leaching process proceeding. Experimentally, even with a small dosage of leachate (0.5 mL), a 94.51% leaching efficiency can be achieved (90 °C, 40 min) for spent LNO materials. Considering that our strategy is not limited to a specific materials system, it could be extended to recycle other valuable materials (including LCO or NCM 811) with minimal leachate usage.
Keywords: deep eutectic solvents; lean leachate; mass transfer; recycling; spent lithium-ion batteries.