(301g) Conductive Membrane Coatings for Improving Current Density in Redox Flow Batteries
- Conference: AIChE Annual Meeting
- Year: 2017
- Proceeding: 2017 Annual Meeting
- Group: Topical Conference: Nanomaterials for Applications in Energy and Biology
- Time: Tuesday, October 31, 2017 - 10:00am-10:20am
A conductive coating of carbon nanotubes (CNTs) and Nafion dispersion in water was used to coat a Nafion 117 membrane via air-assisted electrospraying to improve the rate capability and cycling performance of VRBs. It was found that electrospraying a highly conductive coating directly onto the surface of the membrane allowed for stable cycling performance at nearly double the current density that was afforded by the pristine Nafion membrane. A templating technique was used during the electrospraying process to allow for alternating domains of coated and uncoated membrane surface, which helped reduce the restriction of proton transport across the membrane, further improving rate capability and capacity retention of the VRB. The interfacial resistance between the membrane and the electrode was greatly diminished with the addition of a very small mass (<0.01 mg/cm2) of CNTs. This method has shown to be a fast, simple, and scalable technique for improving the rate capability of vanadium redox flow batteries.
This technique was subsequently extended to a quinone-based aqueous redox flow battery system. While the results were more modest when compared to the VRB system, improvements in current density were still seen with the use of a membrane with a conductive coating.