Date of Award


Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering (PhD)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Lei Pan

Committee Member 1

Timothy C. Eisele

Committee Member 2

Yixin Liu

Committee Member 3

Stephen Hackney


The increased demand for Lithium-ion batteries for Electric vehicles has influenced worldwide interest in the research and development of methods for recycling end-of-life Lithium-ion batteries. Direct recycling method has gained more attention in recent times as a method that is low-cost with the ability to recover all Lithium-ion battery materials without changing the chemical and structural properties of the recycled materials.

A lithium-ion battery contains a complex mixture of materials with significantly different physical properties. This work develops physical separation techniques as Direct recycling methods to recycle individual battery components without damaging the functional integrity of the recycled materials. In this work, froth flotation and gravity are the main physical separation methods applied in combination with other physical pretreatment methods to develop Direct recycling processes that recovers high purity materials.

This work demonstrates how froth flotation can be applied to separate a mixture of two cathode chemistries to have a separation performance of above 95%. The method was applied and used to separate a binary Mixture of NMC111 and LMO cathode chemistries. The separated cathode active materials showed good electrochemical performances.

A Li-saturated froth flotation process was also investigated. This process was used to achieve high separation between NCA and LMO cathode chemistries. It was determined that addition of LiOH reduced the Li loss from NCA cathode during the water-based froth flotation process. A new flake flotation technology was also developed to improve the separation efficiency between anode and cathode electrode materials. For the first time anode and cathode separation results reached up to 99% purity and recovery.

The impact of PVDF removal process on purity, recovery and downstream direct recycling processes was investigated. Detailed bulk and surface material analysis using SEM, STEM, XPS, XRD and ICP analysis was used to determine that mechanical froth flotation separation preserved the stoichiometry and structure of recycled cathode compared to thermally treated cathode.

To obtain ultra-high PVDF free cathode active materials, enhanced gravity separation was used to successfully remove PVDF binder from Recycled cathode active materials, recovering >99% purity cathode active materials without changing the stoichiometry and structure of the recycled cathode materials.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.