A hidden atomic mechanism where Aluminium reacts with other metals in Li-ion batteries making recovery hard and expensive.
A research team at the Hong Kong University of Science and Technology (HKUST) has uncovered a hidden atomic mechanism that hinders the recovery of key metals from used lithium-ion batteries. This discovery challenges long-standing assumptions in battery recycling and may reshape future approaches to battery-to-battery recovery.
The study, recently published in Advanced Science, highlights how aluminium impurities are introduced during the mechanical dismantling of li-ion batteries can penetrate deep into NCM (nickel–cobalt–manganese) cathode materials. Once inside, aluminium atoms chemically bond with oxygen, creating highly stable aluminium–oxygen compounds. This microscopic interaction changes the internal structure of the cathodes and makes it harder to leach out valuable metals such as nickel, cobalt, and manganese.
The mechanism was identified through a combination of atomic-scale imaging and first-principles modelling. The findings show that even trace amounts of aluminium can significantly reduce metal extraction efficiency, especially in conventional acid-based hydrometallurgical recycling systems.
Aluminium was long thought to be a minor contaminant during recycling, but this research reframes it as a major technical bottleneck. It reveals that the impurity doesn’t just coat the surface but becomes embedded within cathode crystals, altering behaviour during metal recovery.
Further investigation into different solvent environments showed that aluminium’s impact varies with chemical conditions. It suppresses metal release in formic acid, enhances it in ammonia, and causes mixed effects in deep eutectic solvents. This underlines the need for chemistry-specific design in battery recycling workflows.
The study offers a new framework for tackling two persistent challenges in LIB recycling: impurity management and energy efficiency. As global demand for EV batteries grows, these insights may help industries develop cleaner, more scalable recovery processes aligned with circular economy goals and climate policy.