Vanadium redox flow batteries (VRFBs) are large-scale electrochemical energy storage systems that enable the supply of stable and reliable power from wind or solar energy. Proton exchange membrane fuel cells (PEMFCs) are efficient and environmentally friendly electro-chemical energy conversion systems that produce only water and heat with clean hydrogen produced using renewable energy as fuel. On the other hand, EHC is an advanced electrochemical system that is indispensable for hydrogen energy cycle systems that purify and compress hydrogen simultaneously.
Sulfonated polyetheretherketone (SPEEK) membranes have been widely regarded as inexpensive proton exchange membranes for electrochemical energy systems such as VRFBs, PEMFCs and EHC due to their ease of fabrication, low cost, good proton conductivity, and excellent thermal and chemical stability.
General requirements for these applications are high proton conductivity, chemical and mechanical stability and impermeability of fuels and oxidants.
In order to improve the performance of membranes, Ju Il Myong, a researcher at the Faculty of Chemical Engineering, developed SPEEK/TiO2 nanopaper composite membranes with TiO2 nanopaper as a backbone and SPEEK polymer as a proton conducting medium, and evaluated their physicochemical properties.
Compared to pristine membranes, the SPEEK/TiO2 nanopaper composite membranes show nearly twice tensile strength, about 1/3 of vanadium permeability and low hydrogen gas permeability, and better performance and long lifetime in VRFB, PEMFC and EHC systems. The experimental results show that SPEEK/TiO2 nanopaper composite membranes can replace commercial Nafion® membranes in electrochemical energy systems.
If more information is needed, please refer to his paper “SPEEK/TiO2 Nanopaper Composite Membranes for Electrochemical Energy Systems” in “Proceedings of KUTIC-2025”.