Date of Award
2025
Degree Type
Thesis
Degree Name
Master of Science in Mechanical Engineering (MSME)
Department
Mechanical, Industrial and Systems Engineering
First Advisor
Ashutosh Giri
Abstract
Lithium-ion batteries have emerged as the dominant energy storage technology for applications ranging from portable electronics, electric vehicles, grid-scale energy storage systems, and even aviation. However, conventional electrode manufacturing processes rely heavily on wet slurry casting methods that employ toxic solvents such as N-methyl-2-pyrrolidone (NMP). This approach presents significant challenges including environmental and health hazards, substantial energy consumption during an extended drying process that can exceed 12-24 hours, high production costs associated with solvent recovery systems, and manufacturing constraints that limit electrode design flexibility and scalability. The elimination of NMP and other solvents are among the first steps to transition to more sustainable manufacturing methods that advance lithium-ion battery production toward more economic viability and environmental safety.
This thesis presents a novel solvent-free electrode fabrication technique that eliminates the use of harmful solvents and combines the benefits of dry powder processing with the precision and flexibility of additive manufacturing. The completely dry process replaces time-intensive solvent evaporation with rapid thermal activation through hot-pressing, reducing processing time from hours to minutes while maintaining or improving electrode performance. By removing the solvent-based slurry casting step, this approach enables more control over electrode morphology, composition, and architecture.
The research focuses on developing and optimizing dry processing methods for lithium titanate (LTO) anodes and lithium iron phosphate (LFP) cathodes. This chemistry was selected for its mechanical and thermal stability, negligible volume change during cycling. The experimental work encompasses investigation of powder mixing protocols, rheological characterization of dry electrode mixtures, optimization of hot-pressing parameters, and comprehensive electrochemical testing in coin cell configurations.
The binder distribution, particle connectivity, and porosity of dry electrodes are achieved fundamentally differently from their wet-processed counterparts due to the absence of solvent-mediated mixing and the unique consolidation mechanisms during thermal activation. These differences are investigated to identify key factors governing dry electrode performance.
The findings demonstrate that properly optimized dry-processed electrodes can achieve electrochemical performance comparable to or exceeding that of conventional wet-processed electrodes while offering significant advantages in manufacturing efficiency, environmental impact, and production cost. These electrodes are capable of significantly higher mass loadings and superior rate capability in comparison to traditionally fabricated electrodes. Which is hypothesized to be from the PVDF binder not clogging the pores of the active material unlike in the wet process.
Recommended Citation
Herchen, Michael, "ADVANCED DRY PROCESSING OF LITHIUM-ION BATTERY ELECTRODES" (2025). Open Access Master's Theses. Paper 2693.
https://digitalcommons.uri.edu/theses/2693