{
  "abstract": "Solid-state electrolytes offer the possibility of safer and higher energy density batteries, yet only a limited number of materials achieve ionic conductivities suitable for practical applications. Type-II superionic conductors, which undergo continuous temperature-driven transitions between low and high ionic conductivity regimes are strong candidates for high-performance solid state electrolytes, but the transition mechanism is not sufficiently understood. In this study, we investigate the archetypical superionic conductors Li2O and Li2S with the antifluorite structure using long-time-scale molecular dynamics simulations with an Allegro machine-learning force field (MLFF) trained on density functional theory data selected using an on-the-fly active learning procedure. To this end, superionic transitions are identified around 1450 K for Li2O and around 1100 K for Li2S through continuous peaks in the heat capacity. Diffusion coefficients and concentration of Frenkel defects are found to exhibit strong non-Arrhenius behavior coinciding with the superionic transition where both diffusion activation energy and defect formation energy decrease significantly across the transition. This suggests a self-enhanced spontaneous defect formation mechanism, which drives the superionic transition and promotes increased ionic diffusion. These results identifies the microscopic origin of type-II superionic behavior as a result of correlated defect formation and support the design of improved solid-state electrolytes.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg Ø, Denmark, 9220"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Timothée Jamin",
      "orcid": "0009-0007-8353-0291"
    },
    {
      "affs": [
        0
      ],
      "name": "Kasper Tolborg",
      "orcid": "0000-0002-0278-115X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/51ytt646q924j.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15010965/v1",
  "fulltext_url": null,
  "id": "51ytt646q924j",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010965/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2208|Advanced Battery Materials and Technologies"
    ]
  ],
  "openalex": "W7223269177",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15010965/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/51ytt646q924j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:26Z",
      "native_id": "10.26434/chemrxiv.15010965",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010965/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "Spontaneous defect formation as the origin of superionic transitions in antifluorite-type structures",
  "title_text": "Spontaneous defect formation as the origin of superionic transitions in antifluorite-type structures",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:26Z",
  "url": "https://research.draconitic.com/paper/51ytt646q924j",
  "venue": "ChemRxiv",
  "versions": []
}