Confined Interlayer Water Explains Fast Proton Intercalation​

February 20, 2020
Confined Interlayer Water Explains Fast Proton Intercalation​
(a) Crystal structure of monoclinic WO3·2H2O showing the interlayer water. (b) Generalized vibrational density of states (GDOS) from INS and (c) ab initio molecular dynamics simulations of the vibrational density of states (VDOS) establish the locations of protons in the material.​

Scientific Achievement

Confined interlayer water in tungsten oxide hydrates (WO3·nH2O) stabilizes the layered structure, which explains the fast electrochemical proton intercalation found in these materials.

Significance and Impact

The work shows that the introduction of confined fluids into redox-active layered materials provides a new strategy for energy storage with both high power and high energy density.

Research Details

  • Quasielastic neutron scattering showed the confined nature of water in WO3·nH2O.
  • Inelastic neutron scattering (INS) and density functional theory (DFT) calculations showed that protons occupy bridging oxygen sites.
  • X-ray diffraction measurements characterized the operando electrochemically induced structural transformation

James B. Mitchell, Natalie R. Geise, Alisa R. Paterson, Naresh C. Osti, Yangyunli Sun, Simon Fleischmann, Rui Zhang, Louis A. Madsen, Michael F. Toney, De-en Jiang, Alexander I. Kolesnikov, Eugene Mamontov, and Veronica Augustyn, “Confined Interlayer Water Promotes Structural Stability for High-Rate Electrochemical Proton Intercalation in Tungsten Oxide Hydrates,” ACS Energy Letters, 4, 2805 (2019). 
DOI: doi.org/10.1021/acsenergylett.9b02040