In Situ Recombination of Elements in Spent Lithium-Ion Batteries to Recover High-Value γ-LiAlO2 and LiAl5O8

Recovering valuable materials from spent lithium-ion batteries is an important task because of the asymmetry in resource distribution, supply, and demand around the world. A lithium-ion battery is a combination system of various elements and their oxides. Current recovering technologies focus on the separation of valuable metal elements. They can inescapably bring secondary contamination and cost to the environment due to the addition of leachants and precipitants. To recover valuable materials, in situ recombination of elements in spent lithium-ion batteries can be a more economical and environment-friendly solution. Herein, we developed a technology based on in situ aluminothermic reduction and interstitial solid solution transformation to recover high-value γ-LiAlO₂ and LiAl₅O₈ under vacuum and high-temperature (1723 K) conditions. It was found that the process of Li₂O filling into the lattice of O-Al-O structure is an energy-reducing process, while LiAl₅O₈ was an existing high-energy transition-state matter. Since there was no wastewater generated, the process brought a new environment-friendly method for recovering valuable metals from spent lithium-ion batteries. This study also provides new comprehension regarding the design for high-value products' recovery from multi-element mixed wastes on an atomic scale.