RPG Student List


Quan LI

Doctor Candidate in Chemical and Biomolecular Engineering

Supervisor: Prof. Ka Ming NG


Research Topic

Recycle and synthesis of lithium ion battery cathode materials


The unique combination of high energy and power density makes lithium ion batteries the best solution for electric vehicles in the near term. In the first chapter, LiNi1/3Mn1/3Co1/3O2 precursor synthesis process is optimized from the particle design perspective. The influence of different factors, including pH, concentration of NH4OH, inner atmosphere, and reaction time, on the quality of the precursor is being investigated. The casual table is used to guide the synthesis of high quality LiNi1/3Mn1/3Co1/3O2 precursors. The second chapter is focused on the process optimization for LiNixMnyCo1-x-yO2 precursor synthesis. With a higher nickel content in the precursor, the necessary changes in the synthesis condition will be identified. To overcome the major drawback of Ni-rich layer cathode material, core-shell structure will be synthesized. Different core to shell molar ratios would be explored to determine the optimal conditions for cathode synthesis.

The increased adoption of LIB in electronic equipment also increases the number of spent batteries being disposed to the landfills. However, disposing spent batteries that contain organic electrolyte and metals such as Ni, Co, Cu, and Li leads to serious environmental problems such as soil and underground water contamination. This is also a waste of the valuable metals contained in the LIBs. The recycling process of cathode materials typically comprises a leaching step and a series of selective precipitation steps to separate and recover metals. A flexible recycle process based on chemical precipitation, oxidation and selective leaching is being designed for metal separation as well as the direct re-synthesis of LIB cathode materials. Different process alternatives have already been generated. Also the current process will be extended to recycle NMC batteries with different N:M:C ratios and possibly other types of LIBs in the market. The unit operations will be identified, and heuristics will be developed for the design of these recycle processes.