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Updated: Oct 24, 2026
Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Two Faces of the Same Oxide: How Crystal Phase Defines the Nature of Proton Storage in MoO3
Zhongxi Li1, Cong Liu1, Zhi Zhang1
1School of Physics & Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Luoyu Road 1037, Wuhan430074, P. R. China.
Abstract:
Proton storage in transition-metal oxides is often linked to fast proton transport, but how crystal phase governs structural evolution, electronic response, and kinetics remains insufficiently understood. Here, α-MoO3 and h-MoO3 are compared as model polymorphs to reveal phase-dependent proton-storage behavior. In situ XRD and state-resolved XPS show that α-MoO3 undergoes an initial irreversible structural reconstruction and then enters a reversible regime with lattice breathing and multivalent Mo redox, exhibiting battery-type behavior and favorable rate capability. In contrast, h-MoO3 rapidly loses long-range order after deep protonation, with poor structural recovery, limited Mo-valence evolution, and predominantly pseudocapacitive charge storage. Electrochemical impedance spectroscopy coupled with distribution of relaxation times analysis and first-principles calculations further indicate that α-MoO3 preserves electronic delocalization and stronger electron-proton coupling, whereas h-MoO3 shows weakened electronic coherence and kinetically dispersed charge compensation. These findings identify structural/electronic coherence as a key criterion for high-performance proton storage.
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