The Critical Role of Atomic-Scale Polarization in Transition Metal Oxides on Vanadium-Redox Electrochemistry

Xiangyang Zhang, Kelong Ao, Jihong Shi, Xian Yue, Agnes Valencia, Xingyi Shi, Weijun Zhou, Fei Liu, Weilu Li, Walid A. Daoud*

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

1 Citation (Scopus)

Abstract

Transition metal oxide electrocatalysts (TMOEs) are poised to revive grid-scale all-vanadium redox flow batteries (VRFBs) due to their low-cost and unique electronic properties, while often inescapably harboring surface vacancies. The role of local vacancy-induced physicochemical properties on vanadium-redox electrochemistry (VRE), encompassing kinetics, and stability, remains profoundly unveiled. Herein, for the first time, it is revealed that vacancies induce atomic-scale polarization in TMOEs and elucidate its mechanism in VRE. Attributable to local polarization, particularly by cation vacancy, the activated nearest-coordinated Mn sites prominently augment the adsorption competence of the V2+/V3+ couple and expedite its round-tripping by forming an intermediate *Mn–O–V bridge. It is also affirmed that the anion vacancies are vulnerable to microstructure reconfiguration by feeble hydroxyl adsorption and thus performance degradation over long-term cycling, in contrast to cation vacancies. Accordingly, the VRFB employing cation-vacancy-functionalized electrode delivers an energy efficiency of 80.8% and a reliable 1000-cycle lifespan with a negligible decay of 0.57% per cycle at 300 mA cm−2, outclassing others. The findings shed light on the fundamental rules governing the utility and evolution of vacancies in TMOEs, thereby moving a step closer toward their deployment in a wide range of sustainable energy storage schemes.

© 2025 Wiley-VCH GmbH
Original languageEnglish
Article number2420510
JournalAdvanced Materials
Volume37
Issue number13
Online published29 Jan 2025
DOIs
Publication statusPublished - 2 Apr 2025

Funding

X.Z., K.A., J.S., and X.Y. These authors contributed equally. The study wassupported by the Research Grants Council of Hong Kong, General Re-search Fund (Grant no. 11306021).

Research Keywords

  • atomic-scale polarization
  • nearest-coordinated Mn
  • transition metaloxide-based electrocatalysts
  • vanadium-redox electrochemistry

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