@article{Duburg2025, 
author = {Jacobus C. Duburg and Jonathan Avaro and Leonard Krupnik and Bruno F.B. Silva and Antonia Neels and Thomas J. Schmidt and Lorenz Gubler},
title = {Design Principles for High-Performance Meta-Polybenzimidazole Membranes for Vanadium Redox Flow Batteries},
year = {2025},
journal = {Energy & Environmental Materials},
volume = {8},
number = {1},
keywords = {design principles, energy storage devices, membranes, polybenzimidazole, vanadium redox flow batteries},
url = {https://www.sciopen.com/article/10.1002/eem2.12793},
doi = {10.1002/eem2.12793},
abstract = {The all-vanadium redox flow battery (VRFB) plays an important role in the energy transition toward renewable technologies by providing grid-scale energy storage. Their deployment, however, is limited by the lack of membranes that provide both a high energy efficiency and capacity retention. Typically, the improvement of the battery’s energy efficiency comes at the cost of its capacity retention. Herein, novel N-alkylated and N-benzylated meta-polybenzimidazole (m-PBI) membranes are used to understand the molecular requirements of the polymer electrolyte in a vanadium redox flow battery, providing an important toolbox for future research toward next-generation membrane materials in energy storage devices. The addition of an ethyl side chain to the m-PBI backbone increases its affinity toward the acidic electrolyte, thereby increasing its ionic conductivity and the corresponding energy efficiency of the VRFB cell from 70% to 78% at a current density of 200 mA cm−2. In addition, cells equipped with ethylated m-PBI showed better capacity retention than their pristine counterpart, respectively 91% versus 87%, over 200 cycles at 200 mA cm−2. The outstanding VRFB cycling performance, together with the low-cost and fluorine-free chemistry of the N-alkylated m-PBI polymer, makes this material a promising membrane to be used in next-generation VRFB systems.}
}