出版者・発行元：Journal of Physical Chemistry B  

Enhancing proton transport in polymer electrolytes is crucial for advancing next-generation solid-state batteries, yet our understanding of proton conductivity in nonaqueous environments remains limited due to a lack of atomic-scale insights. In this study, we investigated the atomic-scale dynamics of 1,2,3-triazole, a small molecule capable of dynamic hydrogen bonding, as a model system for proton hopping in nonaqueous environments. Using the real-space correlation function determined by the double Fourier transformation of inelastic neutron scattering spectra, we identified that the self-motion of protons and intermolecular dynamics occur on comparable time scales. Furthermore, we observed that the activation energy associated with the intermolecular dynamics matches the energy barrier for molecular rotations determined through Density Functional Theory calculations. These findings underscore the importance of controlling molecular dynamics at the atomic scale to control proton transport. Additionally, we demonstrated that intermolecular dynamics in systems involving protons can be studied using inelastic neutron scattering even without deuteration, thereby providing a broader avenue for studying atomic-scale dynamics in soft matter systems.

DOI： 10.1021/acs.jpcb.5c06367

Scopus

担当区分：筆頭著者,　責任著者   出版者・発行元：Journal of Physics Communications  

Normally dielectric relaxation amplitude increases as the temperature decreases. However, certain materials, such as hydrated systems and carboxylic acids, exhibit the opposite manner: i.e. the dielectric relaxation amplitude decreases with decreasing temperature. To elucidate the physical mechanism underlying this phenomenon, a simplified model consisting of a host material and surrounding small solvent molecules that bind to the host surface with a certain probability determined by the binding free energy is considered. This model is solved analytically, yielding a representation of the dielectric amplitude that follows an Arrhenius type behavior in the low temperature limit. This temperature dependence arises from the formation of antiparallel correlations between the dipole moments of solvent molecules due to geometric constraints imposed by the host. It is demonstrated that reported anomalous temperature dependence observed in hydrated proteins, hydrated lithium ions, and acetic acids can be reproduced using this model. Consequently, the universality of this type of the temperature dependence is proposed.

DOI： 10.1088/2399-6528/adc539

Scopus

出版者・発行元：Physical Review E  

We report on the self-part of the Van Hove correlation function, the correlation function describing the dynamics of a single molecule, of water and deuterated water. The correlation function is determined by transforming inelastic scattering spectra of neutrons or x rays over a wide range of momentum transfer Q and energy transfer E to space R and time t. The short-range diffusivity is estimated from the Van Hove correlation function in the framework of the Gaussian approximation. The diffusivity has been found to be different from the long-range macroscopic diffusivity, providing information about local atomic dynamics.

DOI： 10.1103/PhysRevE.109.064608

Scopus

出版者・発行元：Journal of Physical Chemistry B  

Improving the proton transport in polymer electrolytes impacts the performance of next-generation solid-state batteries. However, little is known about proton conductivity in nonaqueous systems due to the lack of an appropriate level of fundamental understanding. Here, we studied the proton transport in small molecules with dynamic hydrogen bonding, 1,2,3-triazole, as a model system of proton hopping in a nonaqueous environment using incoherent quasi-elastic neutron scattering. By using the jump-diffusion model, we identified the elementary jump-diffusion motion of protons at a much shorter length scale than those by nuclear magnetic resonance and impedance spectroscopy for the estimated long-range diffusion. In addition, a spatially restricted diffusive motion was observed, indicating that proton motion in 1,2,3-triazole is complex with various local correlated dynamics. These correlated dynamics will be important in elucidating the nature of the proton dynamics in nonaqueous systems.

DOI： 10.1021/acs.jpcb.3c07685

Scopus

出版者・発行元：IEEJ Transactions on Electrical and Electronic Engineering  

The effects of an AC electric field on ice nucleation temperature and nucleation rate were investigated by freezing distilled water while exposing it to varied AC electric field strengths and frequencies. To eliminate the influence of ion injections and electric field concentrations at a metal electrode surface on ice nucleation, distilled water filled in resin cuvettes are used as samples. The samples are exposed to AC electric field induced by parallel plate electrodes placed outside of the cuvettes. The cuvettes and parallel plate electrodes placed in a freezer with an inside temperature fixed at −15°C. The electric field strength in the sample is 2 or 7.5 kV/m and frequency varies from 50 Hz to 10 kHz. The ice nucleation temperature and the nucleation rate of distilled water increase with increasing the electric field strength and the frequency. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

DOI： 10.1002/tee.23965

Scopus

記述言語：日本語