Mass Transfer and Reaction Kinetic Enhanced Electrode for High‐Performance Aqueous Flow Batteries

Journal Article · 08 August 2019 · Advanced Functional Materials

DOI: https://doi.org/10.1002/adfm.201903192 · OSTI ID:1564573

Mukhopadhyay, Alolika  ^[1]; Yang, Yang ^[1]; Li, Yifan ^[2]; Chen, Yong ^[1]; Li, Hongyan ^[1]; Natan, Avi ^[1]; Liu, Yuanyue ^[2]; Cao, Daxian ^[1]; Zhu, Hongli ^[1]

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1. Department of Mechanical and Industrial Engineering Northeastern University 360 Huntington Avenue Boston MA 02115 USA
2. Department of Mechanical Engineering The University of Texas at Austin 110 Inner Campus Drive Austin TX 78705 USA

Abstract A scalable and efficient process to modify electrodes with enhanced mass transfer and reaction kinetics is critical for redox flow batteries (RFBs). For the first time, this work introduces electrochemical exfoliation as a surface modification method of graphite felt (GF) to enhance the mass transfer and reaction kinetics in RFBs. Anion intercalation and subsequent gas evolutions at room temperature for one minute expand the graphite layers that increase the electrode surface area. Meanwhile, sufficient oxygen functional groups are introduced to the electrode, resulting in enhanced reaction kinetics and improved hydrophilicity. Further, spin‐polarized density functional theory is employed to reveal the role of oxygen functional groups in accelerating the vanadium redox reaction. Benefitting from sufficient oxygen groups, larger surface area, and superior wettability, the as‐prepared exfoliated GF (E‐GF) shows exceptional electrocatalytic activity with minimized overpotential, higher volumetric capacity, and improved energy efficiency. The redox flow battery assembled with the E‐GF electrode delivers voltage and energy efficiencies of 89.72% and 86.41% at the current density of 100 mA cm ⁻² , respectively. Remarkably, compared to the traditional GF treatment method, the elimination of the high temperature and long‐time treatment processes make this approach much more energy and time efficient, scalable, and affordable for large‐scale manufacturing.

• Sponsoring Organization: USDOE
• OSTI ID: 1564573
• Journal Information: Advanced Functional Materials, Journal Name: Advanced Functional Materials Vol. 29 Journal Issue: 43; ISSN 1616-301X
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English