Investigating Non-Solvent Induced Phase Separation as a Fabrication Method for Lithium-Ion Battery Electrodes
Authors: Weiss Trent A. , Brushett Fikile R. 
Published: December 2024

Lithium-ion batteries (LIBs) are considered a key technology in the ongoing sustainable energy transition due to their importance in decarbonizing the transportation and electric power sectors. However, present embodiments cannot fully address the stringent, and often incongruous, performance, cost, and scale requirements associated with current and emerging applications, hindering widespread adoption.1 A critical barrier lies in electrode architectures capable of accommodating the high mass loadings of charge-storage materials needed to increase system-level energy densities and reduce system costs. A direct approach to maximizing electrode areal capacity and, consequently, enhancing energy densities is the use of thicker electrodes (>150 μm). While techniques such as particle alignment via magnetic fields2 and directional ice templating3 have shown promise in producing robust, thick electrodes beyond what is achievable with conventional slurry casting, these methods result in a constrained set of attainable microstructures, thus limiting design flexibility and complicating the understanding of structure-property relationships.

Non-solvent induced phase separation (NIPS), a well-established membrane fabrication approach, holds potential for thick electrode production. Unlike many other processes, NIPS enables greater control over the electrode microstructure through systematic adjustment of reaction precursors and synthesis conditions, supporting the development of complex electrode designs tailored for a diversity of applications.4 Despite its promise, to date only a few studies of NIPS for LIB electrode production exist,5,6 which hampers our understanding of how design parameters impact the resulting electrode structure and performance.

In this presentation, we describe how various process parameters in the NIPS fabrication procedure impact the final LIB electrode morphology, including the loading and distribution of charge-storage materials. Employing a combination of imaging and analytical techniques such as SEM-EDS, XTM, and thermogravimetric analysis, we offer insights into the critical design parameters governing the integration of active materials into the polymer matrix. Electrochemical methods including voltammetry, impedance spectroscopy, and durational cycling are utilized to evaluate performance characteristics and establish connections to the physical structure. We close with a discussion of the implementation of such electrodes into novel cell architectures and the opportunities this may enable for deploying thick electrodes. Overall, this work provides a basis for future optimization of the NIPS methodology, facilitating the advancement of thick electrodes for electrochemical energy storage and conversion.

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