[
    {
        "id": "authors:9rrnx-4f367",
        "collection": "authors",
        "collection_id": "9rrnx-4f367",
        "cite_using_url": "https://authors.library.caltech.edu/records/9rrnx-4f367",
        "type": "publication_workingpaper",
        "title": "Grain Boundary Tuning Determines Iodide and Lithium-Ion Migration in a Solid Adiponitrile-LiI Molecular Crystal Electrolyte",
        "author": [
            {
                "family_name": "Paul",
                "given_name": "Shujit Chandra",
                "orcid": "0000-0003-4007-1615"
            },
            {
                "family_name": "Goddard",
                "given_name": "William A., III",
                "orcid": "0000-0003-0097-5716",
                "clpid": "Goddard-W-A-III"
            },
            {
                "family_name": "Zdilla",
                "given_name": "Michael J.",
                "orcid": "0000-0003-0212-2557"
            },
            {
                "family_name": "Prakash",
                "given_name": "Prabhat",
                "orcid": "0000-0003-1430-2379",
                "clpid": "Prakash-Prabhat"
            },
            {
                "family_name": "Wunder",
                "given_name": "Stephanie L.",
                "orcid": "0000-0002-7193-4762"
            }
        ],
        "abstract": "<p>This work presents the synthesis of a molecular crystal of adiponitrile (Adpn) and LiI via a simple melting method. The molecular crystal has both Li\u207a and I\u207b channels and can be either a Li\u207a or I\u207b conductor. In the stoichiomnetric crystal (Adpn)\u2082LiI, the Li\u207a ions interact only with four C&equiv;N groups of Adpn while the I\u207b ions are uncoordinated. Ab initio calculations indicate that the activation energy for ion hopping is less for the I\u207b (E\u2090 = 60 kJ/mol) than for the Li\u207a (E\u2090 = 93 kJ/mol) ions, and is predominantly an I\u207b conductor, with a lithium-ion transference number (t_Li\u207a) of t_Li\u207a = 0.15, no lithium plating/stripping observed in the cyclic voltammograms (CVs), and a conductivity of &sigma; = 10\u207b\u2074 S/cm at 30 \u1d52C. With the addition of excess adiponitrile, which resides in the grain boundaries between the crystal grains, the contribution of Li\u207a ions to the conductivity increases, so that for the nonstoichiometric molecular crystal (Adpn)\u2083LiI, Li&harr; Li\u207a redox reactions are observed in the CVs, t_Li\u207a = 0.63, conductivity increases to &sigma; = 10\u207b&sup3; S/cm 30 \u1d52C, the voltage stability window is 4V, and it is thermally stable to 130 \u1d52C, showcasing the potential of this electrolyte for advanced solid-state Li-I battery applications. The solid (Adpn)\u2083LiI minimizes migration of polyiodides, inhibiting the &ldquo;shuttle&rdquo; effect.</p>",
        "doi": "10.26434/chemrxiv-2025-q7r85",
        "publisher": "ChemRxiv",
        "publication_date": "2025-05-16"
    }
]