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Stabilizing Superionic-Conducting Structures via Mixed-Anion Solid Solutions of Monocarba-Closo-Borate Salts



Wan Si NMN Tang, Koji Yoshida, Alexei V. Soloninin, Roman V. Skoryunov, Olga A. Babanova, Alexander V. Skripov, Mirjana NMN Dimitrievska, Vitalie Stavila, Shin-Ichi Orimo, Terrence J. Udovic


Solid lithium and sodium closo-polyborate-based salts are capable of superionic conductivities surpassing even liquid electrolytes, but often only at above-ambient temperatures where their entropically driven disordered phases become stabilized. Here we show by X-ray diffraction, quasielastic neutron, differential scanning calorimetry, NMR, and AC impedance measurements, that by introducing "geometric frustration" via the mixing of two different closo-polyborate anions, namely, 1-CB9H10- and CBd11^H^d12-, to form solid-solution anion-alloy salts of lithium or sodium, we can successfully suppress the formation of possible ordered phases in favor of disordered, fast-ion-conducting ally phases over a broad temperature range from sub-ambient to high temperatures. This result exemplifies an important advancement for further improving on the remarkable conductive properties generally, displayed by this class of materials, and represents a practice strategy tailored, ambient-temperature, solid, superionic conductors for the variety of upcoming all-solid-state energy devices of the future.
ACS Energy Letters


Closo-borates, Diffraction, Ionic Conductivities, Neutron Fixed-Window Scans, NMR, Reorientational Dynamics, Solid Solutions, Solid-State Conductors, Superionic


Tang, W. , Yoshida, K. , Soloninin, A. , Skoryunov, R. , Babanova, O. , Skripov, A. , Dimitrievska, M. , Stavila, V. , Orimo, S. and Udovic, T. (2016), Stabilizing Superionic-Conducting Structures via Mixed-Anion Solid Solutions of Monocarba-Closo-Borate Salts, ACS Energy Letters, [online], (Accessed April 17, 2024)
Created August 31, 2016, Updated October 12, 2021