Scaling up Electrode Manufacturing with Non-Solvent Induced Phase Separation Technology

Abstract

Grid-scale energy storage technologies must be deployed at a massive scale to balance the mismatch between energy generation using renewable technologies and demand. Redox flow batteries are an emerging technological option for large-scale and multi-hour electrochemical energy storage thanks to their ability to decouple energy and power1. Despite their intrinsic advantages, the current elevated costs of this technology hinders commercialization2. To improve cost competitiveness, research efforts have focused on developing novel electrolyte chemistries and optimized reactor concepts. To the latter, optimizing the porous electrode microstructure and surface chemistry offers a promising pathway to increase the performance of flow batteries. However, porous electrodes design is challenging as they must fulfil contradictory requirements such as providing high surface area for electrochemical reactions, facilitating mass transport of reactive species, and maintaining low operational pressure drop. Furthermore, state-of-the-art porous electrodes have been repurposed from other mature electrochemical technologies but have not been tailored for the unique requirements of redox flow batteries3.Non-solvent induced phase separation (NIPS) has been recently introduced as a versatile method to synthesize porous structures suitable for RFBs with unique properties, which are unattainable with current fibrous materials4,5. Drawing inspiration from membrane fabrication techniques, we reengineered the method for the synthesis of porous electrodes for use in redox flow batteries. The porous electrodes synthesized with NIPS were tested in a single-electrolyte cell configuration and then in an all-vanadium redox flow battery, showing promising electrochemical performance in comparison with existing commercial fibrous carbon materials. In this presentation, I will discuss our current efforts to scale up the NIPS method to manufacture electrodes at industrial scale. We believe that non-solvent induced phase separation is a cost-effective alternative to traditional carbon fibrous materials thanks to the few simpler steps required for the electrode preparation. Based on technoeconomic modeling, we estimate that the production cost of the NIPS electrodes can be less than half of the production costs of traditional carbon fibrous electrodes6. Moreover, the phase separated electrodes do not require post-manufacturing heat treatment to increase the surface area and wettability, which further translates into savings on energy costs. In this project, we aspire to scale-up the NIPS materials to a final size, after carbonization, of 30·30 cm2 while retaining similar microstructural and electrochemical performance properties as in laboratory scale. We perform a suite of microscopy, spectroscopic and flow cell diagnostics to correlate the electrode microstructure, surface chemistry and device performance. In this presentation, I will discuss the scalability of the method, reproducibility based on statistical analysis of sample properties and performance, and finally electrochemical performance on two flow battery chemistries.References Markard, J. (2018). The next phase of the energy transition and its implications for research and policy. Nature Energy, 3(8), 628-633.Darling, R. M. (2022). Techno-economic analyses of several redox flow batteries using levelized cost of energy storage. Current Opinion in Chemical Engineering, 37, 100855.Forner-Cuenca, A., and Brushett, F. R. (2019). Engineering porous electrodes for next-generation redox flow batteries: recent progress and opportunities. Current Opinion in Electrochemistry, 18, 113-122.Wan, C. T. C., Jacquemond, R. R., Chiang, Y. M., Nijmeijer, K., Brushett, F. R., & Forner‐Cuenca, A. (2021). Non‐Solvent Induced Phase Separation Enables Designer Redox Flow Battery Electrodes. Advanced Materials, 33(16), 2006716.Jacquemond, R. R., Wan, C. T. C., Chiang, Y. M., Borneman, Z., Brushett, F. R., Nijmeijer, K., & Forner-Cuenca, A. (2022). Microstructural engineering of high-power redox flow battery electrodes via non-solvent induced phase separation. Cell Reports Physical Science, 3(7), 100943.Minke, Christine, Ulrich Kunz, and Thomas Turek. "Carbon felt and carbon fiber-A techno-economic assessment of felt electrodes for redox flow battery applications." Journal of Power Sources342 (2017): 116-124.