Composite Polybenzimidazole Membrane with High Capacity Retention for Vanadium Redox Flow Batteries

Abstract

Currently, energy storage technologies are becoming essential in the transition of replacing fossil fuels with more renewable electricity production means. Among storage technologies, redox flow batteries (RFBs) can represent a valid option due to their unique characteristic of decoupling energy storage from power output. To push RFBs further into the market, it is essential to include low-cost materials such as new generation membranes with low ohmic resistance, high transport selectivity, and long durability. This work proposes a composite membrane for vanadium RFBs and a method of preparation. The membrane was prepared starting from two polymers, meta-polybenzimidazole (6 mm) and porous polypropylene (30 μm), through a gluing approach by hot-pressing. In a vanadium RFB, the composite membrane exhibited a high energy efficiency (~84%) and discharge capacity (~90%) with a 99% capacity retention over 90 cycles at 120 mA∙cm−2, exceeding commercial Nafion® NR212 (~82% efficiency, capacity drop from 90% to 40%) and Fumasep® FAP-450 (~76% efficiency, capacity drop from 80 to 65%).

Correction: Duburg et al. Composite Polybenzimidazole Membrane with High Capacity Retention for Vanadium Redox Flow Batteries. Molecules 2021, 26, 1679

“…In this case, the wet weight was measured in a vial to reduce the evaporation of water from the membrane. Lastly, water and electrolyte uptake of pristine m-PBI and of commercial membranes NR212 and FAP-450 was calculated according to Equation (1).…”

Recent Advances in Functional Polymer Materials for Energy, Water, and Biomedical Applications: A Review

“…Conducting polymers (CPs) have received a lot of attention due to their economic importance, good environmental stability, and electrical conductivity, as well as their useful mechanical, optical, and electronic properties. Generally, conducting polymers have different nanostructures with a higher specific capacitance and may constitute an alternative in the development of new-generation energy storage devices [45][46][47][48][49][50]. There are many types of conducting polymers that have the ability to conduct electrical current.…”

Side-Chain Grafting-Modified Sulfonated Poly(ether ether ketone) with Significantly Improved Selectivity for a Vanadium Redox Flow Battery

“…So far, because of its extraordinarily high conductivity and outstanding chemical stability, Nafion membranes are still one of the finest choices for VRFB ion-selective membranes . However, the drawbacks of a high expansion rate, substantial vanadium ion penetration, and high cost are the key issues for large-scale deployment of Nafion membranes in VRFBs. , Many efforts have been made to date to produce innovative ion-selective membranes with improved performance and cheaper costs, such as cross-linking-modified − and polymer-blended composite membranes. − Because of their low cost, stability, and ease of manufacture, sulfonated poly­(ether ether ketone) membranes (SPEEK) have received a lot of interest. ,,,− Amphoteric ion exchange membranes with fixed cations and anion exchange groups have received a lot of interest in recent years. , Due to electrostatic repulsion, the positive ion group can effectively prevent the positive diffusion of vanadium ions under battery operating conditions, while the negative ion group provides optimum proton conductivity. Sulfamic acid (SA) contains −SO 3 H (acidic) and −NH 2 (weak basic) groups, which can be used to replace the inherent conductivity/permeability balance of the proton exchange membrane …”