Abstract
There is widespread interest in determining the structural features of redox-active electrochemical energy storage materials that enable simultaneous high power and high energy density. Here, we present the discovery that confined interlayer water in crystalline tungsten oxide hydrates, WO3·nH2O, enables highly reversible proton intercalation at subsecond time scales. By comparing the structural transformation kinetics and confined water dynamics of the hydrates with anhydrous WO3, we determine that the rapid electrochemical proton intercalation is due to the ability of the confined water layers to isolate structural transformations to two dimensions while stabilizing the structure along the third dimension. As a result, these water layers provide both structural flexibility and stability to accommodate intercalation-driven bonding changes. This provides an alternative explanation for the fast energy storage kinetics of materials that incorporate structural water and provides a new strategy for enabling high power and high energy density with redox-active layered materials containing confined fluids.
| Original language | English |
|---|---|
| Pages (from-to) | 2805-2812 |
| Number of pages | 8 |
| Journal | ACS Energy Letters |
| Volume | 4 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 13 2019 |
Funding
We thank Nikki Creange, John McGarrahan, Carolyn Grimley, and Prof. Elizabeth Dickey for assistance with pellet pressing and the temperature-controlled stage for impedance measurements. We also thank Michael Spencer for performing scanning electron microscopy. J.B.M., A.R.P., and V.A. acknowledge support from the National Science Foundation under Grant No. 1653827 for material synthesis, electrochemical characterization, and XRD. N.C.O., Y.S., D.J., A.I.K., and E.M. acknowledge funding from the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences for neutron scattering and computation. N.R.G. was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program. R.Z. and L.A.M. acknowledge funding from the National Science Foundation under Award DMR 1810194 for SSNMR. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. DOE under Contract No. DEAC05-00OR22725. SEM and ex situ XRD was performed at the Analytical Instrumentation Facility (AIF) at North Carolina State University (NCSU), which is supported by the State of North Carolina and the National Science Foundation (Grant ECCS-1542015). The AIF is a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), a site in the National Nanotechnology Coordinated Infrastructure (NNCI).
| Funders | Funder number |
|---|---|
| A.R.P. | |
| E.M. | |
| Energy Frontier Research Center | |
| Fluid Interface Reactions, Structures and Transport | |
| Office of Basic Energy Sciences | |
| U.S. DOE | |
| UT-Battelle | |
| V.A. | |
| XRD | |
| National Science Foundation | 1653827, 1810194 |
| U.S. Department of Defense | DoD |
| U.S. Department of Energy | |
| Foundation for Ichthyosis and Related Skin Types | |
| Office of Science | |
| Oak Ridge National Laboratory | |
| North Carolina State University | ECCS-1542015, NCSU |
| National Defense Science and Engineering Graduate | DMR 1810194 |
