DOI
https://doi.org/10.25772/851R-BV32
Author ORCID Identifier
0000-0003-4319-4725
Defense Date
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemical and Life Science Engineering
First Advisor
Dr. Mo Jiang
Second Advisor
Dr. Ram B. Gupta
Third Advisor
Dr. Nastassja Lewinski
Fourth Advisor
Dr. Hani El-Kaderi
Fifth Advisor
Dr. Maryanne Collinson
Abstract
There are various ways to produce lithium nickel manganese cobalt oxide (NCM) based cathodes for lithium-ion batteries, among them; co-precipitation synthesis carried out in tank-based reactors followed by lithiation is commonly employed because of its cost-effectiveness and scalability. Although it is the preferred synthesis method, it has several issues and challenges. Discussed in this dissertation are some of these issues as well as potential solutions. Physical and chemical properties of the co-precipitation product such as yield, particle size, morphology, and tap density, depend on various reaction parameters, which include pH, chelating agents, metal salt concentrations, and stirring speed. In the first work, theoretical modeling and experimental work are utilized to understand the interdependence between the particle properties and reaction conditions as well as to optimize the reaction parameters. Traditional stirred tank-based co-precipitation manufacturing process for NCM precursors suffers from inhomogeneity in the reaction environment, which leads to non-uniform morphology and particle size distribution (PSD). Therefore, in the second work, a slug-flow-based manufacturing platform, which offers a homogeneous reaction environment, is used for the continuous production of NCM-based cathode precursors. Due to the polycrystalline nature of the NCM 111 particles, during long term cycling, particles develop micro cracks due to electrolyte penetration in the particle grain boundaries that result in particles breaking apart. Particles with minimal or grain boundaries known as single crystal particles are proposed as a solution. In the third work, the single crystal material is produced from slug flow derived NCM 111 oxalate using eutectic salt and high temperatures. In the fourth work, a mathematical model that can predict the secondary particle size distribution of NCM 111 oxalate produced using various reaction conditions is proposed. This model consists of three distinct parts: solution equilibrium, nucleation and growth as well as aggregation and fragmentation.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-9-2024