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Enabling high rate capability, low internal resistance, and excellent cyclability for vanadium redox flow batteries utilizing ultrafast laser-structured graphite felt

Daugherty, Michael C.; Hsieh, Chien-Te; Aaron, Doug S.; Ashraf Gandomi, Yasser; Li, Jianlin; Zheng, Yijing; Pfleging, Wilhelm

Abstract:
The electrochemical performance of vanadium redox flow batteries (VRFBs) was enhanced via laserpatterned graphite felt (GF) electrodes. The laser-structured GF electrodes engineered via preparing a series of well-ordered microscopic channel structures with an average width of 200 mm, creating a threedimensional carbon framework. The ultrafast laser patterning increased the porosity by 10%, as compared to pristine electrode. The analysis of the overpotential distribution using
electrochemical impedance spectroscopy revealed that the electrode polarization involving charge transfer and diffusion resistance is strongly alleviated with the aid of carbon micro-perforation. The advanced design of laserstructured GF electrode also exhibits high rate capability, low internal resistance, and excellent cyclability.
The improved performance was attributed to the synergistic effect involving (i) high electrochemically active surface area for rapid electrochemical reactions (i.e., V(II)/V(III) and V(IV)/V(V) redox couples) and (ii) excellent transport properties for facile electron/ion/species transport. The micro-scale channels created with the laser-ablation technique act as capillary structures and enabled homogeneous and rapid wetting of GF electrodes as formulated with the classical Washburn equation. ... mehr



Originalveröffentlichung
DOI: 10.1016/j.electacta.2020.136171
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Angewandte Werkstoffphysik (IAM-AWP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 06.2020
Sprache Englisch
Identifikator ISSN: 0013-4686
KITopen-ID: 1000118673
HGF-Programm 37.01.02 (POF III, LK 01)
Components and Cells
Erschienen in Electrochimica acta
Band 344
Seiten 136171
Projektinformation DFG, DFG EIN, PF 392/9-1
Schlagwörter KNMF 2018-019-021389 LMP
Nachgewiesen in Scopus
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