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Updated: Jan 20, 2026

Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets
Published on: February 22, 2016
In Operando Visualization of the Electrochemical Formation of Liquid Polybromide Microdroplets
Yutong Wu1, Po-Wei Huang1, Joshua D Howe2
1School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Abstract:
Zinc-bromine flow batteries are promising for stationary energy storage, and bromine-complexing agents have been used to form phase-separated liquid polybromide products. However, an understanding of the dynamics of polybromide nucleation is limited due to the beam sensitivity and complexity of polybromides. Here we report an in operando platform composed of dark-field light microscopy and a transparent electrochemical cell to reveal the dynamics of polybromide formation in their native environment. Using our platform, we confirm and reveal the liquid nature, chemical composition, pinning effect (strong interaction with Pt), residual effect (residual charge products on the surface), self-discharging, and over-oxidation of the polybromide products. The results provide insights into the role of complexing agents and guide the future design of zinc-bromine flow batteries. Furthermore, our in operando platform can potentially be used to study sensitive species and phases in other electrochemical reactions.
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