Affiliation:
1. School of Chemistry University of New South Wales Sydney NSW 2052 Australia
2. Advanced Li‐ion battery lab Ningbo Institute of Material Technology and Engineering Chinese Academy of Science Ningbo 315200 P. R. China
3. School of Chemical Sciences The University of Auckland Auckland 1142 New Zealand
4. Helmholtz Institute Ulm 89081 Ulm Germany
Abstract
AbstractRapid proton transport in solid‐hosts promotes a new chemistry in achieving high‐rate Faradaic electrodes. Exploring the possibility of hydronium intercalation is essential for advancing proton‐based charge storage. Nevertheless, this is yet to be revealed. Herein, a new host is reported of hexagonal molybdates, (A2O)x·MoO3·(H2O)y (A = Na+, NH4+), and hydronium (de)intercalation is demonstrated with experiments. Hexagonal molybdates show a battery‐type initial reduction followed by intercalation pseudocapacitance. Fast rate of 200 C (40 A g−1) and long lifespan of 30 000 cycles are achieved in electrodes of monocrystals even over 200 µm. Solid‐state nuclear magnetic resonance confirms hydronium intercalations, and operando measurements using electrochemical quartz crystal microbalance and synchrotron X‐ray diffraction disclose distinct intercalation behaviours in different electrolyte concentrations. Remarkably, characterizations of the cycled electrodes show nearly identical structures and suggest equilibrium products are minimally influenced by the extent of proton solvation. These results offer new insights into proton electrochemistry and will advance correlated high‐power batteries and beyond.
Funder
Australian Research Council
University of New South Wales
Australian Synchrotron
National Natural Science Foundation of China
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science