Optimization of electrode characteristics for the Br2/H2 redox flow cell

Publication Type

Journal Article

Date Published

01/2015

Authors

DOI

Abstract

The Br2/H2 redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (−) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (−) catalyst layer on the membrane instead of on the carbon paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm−2 and a peak power density of 1.4 W cm−2. Maximum energy efficiency of 79% is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br reversibly adsorbs at the Pt (−) electrode for potentials exceeding a critical value, and the extent of Br coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.

Journal

Journal of Applied Electrochemistry

Volume

45

Year of Publication

2015

Issue

1

ISSN

0021-891X

Organization

Research Areas