# Not all H atoms contribute to low activation barrier diffusion in Ba1.75LiH2.7O0.9

https://mdr.nims.go.jp/datasets/636bc7c7-9b8c-47dd-ac01-4e282565be97

## File

- [TSTM-2026-0004_data_corrected.zip](https://mdr.nims.go.jp/filesets/7171fed8-56e5-4c47-b7f0-0bec2460695e/download) ([Detail](https://mdr.nims.go.jp/filesets/7171fed8-56e5-4c47-b7f0-0bec2460695e.md))
- [AgI_BLHO_20260602_corrected.pdf](https://mdr.nims.go.jp/filesets/674d4254-2393-46b9-925e-9bf341809004/download) ([Detail](https://mdr.nims.go.jp/filesets/674d4254-2393-46b9-925e-9bf341809004.md))
- [Supplementary_BLHO_corrected.pdf](https://mdr.nims.go.jp/filesets/e7b4b84f-80c6-48e2-a360-a4a9fdaf946f/download) ([Detail](https://mdr.nims.go.jp/filesets/e7b4b84f-80c6-48e2-a360-a4a9fdaf946f.md))

## Id

636bc7c7-9b8c-47dd-ac01-4e282565be97

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2026-10-01T06:31:31.538803Z

## Updated at

2026-10-01T07:17:50.786366Z

## Published at

2026-10-01T09:35:21.855065Z

## Doi

https://doi.org/10.48505/nims.8635

## First published url

https://doi.org/10.1080/27660400.2026.2676562

## Date published

2026-12-31

## Recorded date published

2026-12-31

## Resource type

journal_article

## Manuscript type

accepted_manuscript

## Collection



## Title

- title: Not all H atoms contribute to low activation barrier diffusion in Ba1.75LiH2.7O0.9
  title_type: original
  lang: en

## Description

- description: Superionic conductors have extremely high conductivity in some constituent
    ions even in the solid state, and many lose their superionicity below a critical
    temperature. The conductivity of K2NiF4 structure-based Ba1.75LiH2.7O0.9 jumps
    over three orders of magnitude at ~ 573 K. This jump is not at a first-order structural
    phase transition temperature. Molecular dynamics (MD) simulations using a density
    functional theory (DFT) trained universal neural network potential (NNP) were
    conducted in this study. The Arrhenius plot of the tracer diffusion coefficient
    is a straight line between 455 and 741 K, inconsistent with the conductivity jump.
    The 3D activation barrier is ~0.3 eV, which is much lower than typical K2NiF4
    structure-based oxyhydrides. The features in the radial distribution function
    are almost temperature independent. However, statistical inspection of the tracer
    diffusion coefficient for each atom, which is very difficult with DFT-MD but is
    feasible with NNP-MD, revealed the existence of effectively immobile H atoms over
    the entire studied temperature range. Most H do not engage in concerted migration,
    according to a comparison with a universal curve for independent random walkers.
    These findings hold for all phases, which have different distributions of Li,
    O, and H atoms in the same structural framework. Incorporating many vacancies,
    especially in ‘K’ sites of the K2NiF4 framework, could form a low activation barrier
    H diffusion network not available in conventional oxyhydrides with the same framework.
    Gaining access to such a percolating network above a certain temperature can explain
    the superionic transition at this temperature.
  description_type: abstract
  lang: en

## Creator

- name: Yoyo Hinuma
  role: author
  organization: National Institute of Advanced Industrial Science and Technology (AIST)
  department: Department of Energy and Environment

## Contact agent



## Publisher

organization: Taylor & Francis

## Managing organization



## Keyword

- subject: Superionic conductivity
  schema: not_defined
- subject: tracer diffusion coefficient
  schema: not_defined
- subject: molecular dynamics
  schema: not_defined
- subject: neural network potential
  schema: not_defined
- subject: Ba1.75LiH2.7O0.9
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

## Other identifier(s)



## Data origin

- data_origin_type: other

## Embargo



## Journal

- title: Science and Technology of Advanced Materials
  issn: '27660400'
  volume: '6'
  article_number: '2676562'

## Conference



## Related item



## Funding



## Instrument



## Instrument operator



## Instrument managing organization



## Measurement method



## Specimen



## Chemical composition



## Structure for specimen



## Structural feature for specimen



## Specific property for specimen



## Process for specimen treatment



## Computational method



## Energy level/transition state



## Software



## Custom property



## Fileset

- id: 7171fed8-56e5-4c47-b7f0-0bec2460695e
  filename: TSTM-2026-0004_data_corrected.zip
  content_type: application/zip
  size: 3299709
  md5: 0041fe6b08040dc1dcbac8a33862e30d
- id: 674d4254-2393-46b9-925e-9bf341809004
  filename: AgI_BLHO_20260602_corrected.pdf
  content_type: application/pdf
  size: 10202272
  md5: baa87aab64790ab825d0322e1d779eed
- id: e7b4b84f-80c6-48e2-a360-a4a9fdaf946f
  filename: Supplementary_BLHO_corrected.pdf
  content_type: application/pdf
  size: 2598205
  md5: 49e112cc526b7ed668b9deffcdc3d1aa

## Thumbnail

fileset_id: 674d4254-2393-46b9-925e-9bf341809004
filename: AgI_BLHO_20260602_corrected.pdf