A Fully Integrated Experimental Platform for Benchmarking New Flow Battery Active Materials

Redox flow batteries (RFBs) have the potential to be low-cost solutions for grid-scale energy storage needs. The DOE recommends that RFBs should approach cost targets of $100/kWh to enable widespread deployment, and it will be challenging to meet this target with current-generation active materials like vanadium [1]. Technoeconomic models have shown that decreasing electrolyte cost and increasing battery voltage will both be crucial for improving cost performance in functional RFB modules [2]. These opportunities lend well to leveraging molecular and materials design strategies for new RFB electrolytes, but the field still lacks a standard set of tools and techniques (analogous to coin-cell testing in the Li-ion battery field) to support rapid, credible comparisons across newly developed electrolyte materials.

This presentation will describe our work to develop a fully integrated, small-volume electrochemical flow platform that measures the thermodynamic, kinetic, and transport properties of RFB electrolytes, spanning inorganic and organic materials as well as soluble and suspended solids. Using a first-generation prototype, we have validated prior work on the sensitivity of the Fe(3+/2+) redox couple to the surface composition of carbon electrodes. We will also discuss ongoing work to further develop the flow platform for studying the redox properties of metal oxide nanomaterials under flow.

[1] Paul Spitsen. Energy Storage Grand Challenge Roadmap. Technical report, 2020.

[2] Robert M. Darling, Kevin G. Gallagher, Jeffrey A. Kowalski, Seungbum Ha, and Fikile R. Brushett.Pathways to low-cost electrochemical energy storage: A comparison of aqueous and nonaqueous flow batteries.Energy and Environmental Science, 7(11):3459–3477, 11 2014.