Enhancement of Electrochemical Performance in Pvdf-Co-Hfp Cation Exchange Membrane with Modifications by Doping Pp13-Tfsi Ionic Liquid and Sulfonation

Abstract

Polyvinylidene fluoride-hexafluoropropylene (PVDF-co-HFP) is a material that has garnered interest in the field of electrochemical systems because of its facile moldability into various shapes and sizes of membranes, positioning it as a highly promising alternative to high-cost commercial membranes. Nevertheless, enhancing its electrochemical characterization remains a pivotal challenge to be surmounted for its broad adoption. In this study, a novel PVDF-co-HFP membrane, augmented with PP13-TFSI ionic liquid and sulfonation (Membrane P-I&S), was successfully synthesized, and its potential as an ion exchange membrane in microbial fuel cells (MFCs) was evaluated. The findings indicated that chlorosulfonic acid considerably enhances the hydrophilicity and proton transport properties of PVDF-co-HFP, with the ionic liquid posited as an effective means to augment the sulfonation effect. Membrane P-I&S exhibited the highest key performance parameters among four composite membranes of identical thickness. It also revealed more fluorine (F) and sulfur (S) concentrations and contained more functional groups, such as S=O, –SO3H, –CF2, and –CF3. An MFC incorporating Membrane P-I&S demonstrated a remarkable current production capacity and power density, exceeding those of the unmodified membrane by more than two and threefold, respectively. In addition, the MFC based on Membrane P-I&S displayed prolonged cycling stability with a notably porous architecture and enhanced biofouling resistance. This study validates the development of a high-efficiency, cost-effective, and environmentally friendly membrane fabrication approach for application in bioelectrochemical systems.

Keywords: Ionic Liquid, Sulfonation, Electrochemical performance, PVDF-co-HFP Membrane, MFC