Disclosed are redox flow battery membranes, redox flow batteries incorporating the membranes, and methods of forming the membranes. The membranes include a densified polybenzimidazole gel membrane that is capable of incorporating a high liquid content without loss of structure that is formed according to a process that includes in situ hydrolysis of a polyphosphoric acid solvent followed by densification of the gel membrane. The densified membranes are then imbibed with a redox flow battery supporting electrolyte such as sulfuric acid and can operate at very high ionic conductivities of about 50 mS/cm or greater and with low permeability of redox couple ions, e.g. vanadium ions, of about 10−7 cm2/s or less. Redox flow batteries incorporating the membranes can operate at current densities of about 50 mA/cm2 or greater.
Benicewicz, Brian C., et al. "Low permeability polybenzimidazole (PBI) gel membranes for redox flow batteries." US 11,482,721, United States Patent and Trademark Office, Oct. 2022.
Benicewicz, Brian C., Murdock, Laura, Wang, Lihui, et al., "Low permeability polybenzimidazole (PBI) gel membranes for redox flow batteries," US 11,482,721, issued October 25, 2022.
@misc{osti_1986752,
author = {Benicewicz, Brian C. and Murdock, Laura and Wang, Lihui and Huang, Fei and Pingitore, Andrew},
title = {Low permeability polybenzimidazole (PBI) gel membranes for redox flow batteries},
annote = {Disclosed are redox flow battery membranes, redox flow batteries incorporating the membranes, and methods of forming the membranes. The membranes include a densified polybenzimidazole gel membrane that is capable of incorporating a high liquid content without loss of structure that is formed according to a process that includes in situ hydrolysis of a polyphosphoric acid solvent followed by densification of the gel membrane. The densified membranes are then imbibed with a redox flow battery supporting electrolyte such as sulfuric acid and can operate at very high ionic conductivities of about 50 mS/cm or greater and with low permeability of redox couple ions, e.g. vanadium ions, of about 10−7 cm2/s or less. Redox flow batteries incorporating the membranes can operate at current densities of about 50 mA/cm2 or greater.},
url = {https://www.osti.gov/biblio/1986752},
place = {United States},
year = {2022},
month = {10},
note = {US Patent