Sub-project 3.1

Purify and investigate the effect of metallic impurities of black mass on the DES 2.0 process

Theme 1

The black mass from the spent Li-ion batteries may contain trace metallic impurities such as the Fe, Al, and Cu, which will affect the following DES 2.0 process. In this process, we will develop new hydrometallurgical processes either using DES or new leaching solvents to remove and control the amount of purities. The new process aims to selective ionization of metallic contaminants while not driving the breakdown of the physicochemical structure of the active cathode materials. The impacts of treatment on the chemical/structural/morphological changes of black mass will be also investigated. We will also conduct the research to understand how the treatment and impurity will affect the following DES process.

Sub-project 3.2

Upgrade the DES 2.0 process by developing new DES and anti-solvents

Theme 2

Although we are scaling-up the DES 2.0 process, we can still upgrade the process to enhance the selectivity and purity. We will develop new DES and new anti-solvent to enhance the selectivity of each metal elements (e.g. Li, Co, Ni, Mn) and purity of the recovery compounds. We will also study external assistances including additional reductants and microwave enhancement to further increase the metal leaching and selective efficiency. Various methods such as water addition, component supplement, or pH adjustment will be also explored to increase the DES recyclability.

Sub-project 3.4

Design different functional DESs for the selective recovery of metals from different lithium-ion batteries

Theme 2

In this project, we will screen different hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) to construct functional deep eutectic solvents (DESs), where each DES provides a distinct ligand environment. By leveraging the differences in chemical properties among coordination complexes formed between ligand ions and transition metal ions, we aim to achieve high-purity selective recovery. Our work will focus on investigating how different ligand ions influence the leaching behavior of spent battery materials and further elucidate the speciation of transition metals within DESs. This is expected to provide a strong theoretical foundation and support for the development of next-generation DES 2.0 systems.