Publications

Liquid-Like Ionic Conduction in Solid Lithium and Sodium Monocarba-closo-Decaborates Near or at Room Temperature

Tang, Wan S.; Matsuo, Motoaki; Wu, Hui; Stavila, Vitalie S.; Zhou, Wei; Talin, Albert A.; Soloninin, Alexei V.; Skoryunov, Roman V.; Babanova, Olga A.; Skripov, Alexander V.; Unemoto, Atsushi; Orimo, Shin I.; Udovic, Terrence J.

The search for solid electrolytes with sufficiently high ionic conductivities and stabilities is underway to enable the commercial viability of all-solid-state rechargeable batteries. LiCB9H10 and NaCB9H10 compounds exhibit the most impressive superionic conductivities yet among complex-hydride-based materials, including this class of large-polyhedral-anion-based salts. The pseudoaromatic nature of the CB9H10 anions makes them relatively stable like their B12H122-, B10H102-, and CB11H122- cousins, rendering their salts prime candidates for incorporation into next-generation, all-solid-state devices. Preliminary cyclic voltammetry measurements indicate that only cathodic and anodic currents are observed near 0 v corresponding to Li/Na deposition on the Au electrode and Li/Na stripping, respectively, without signifi cant anodic currents, at least ≤ 5 v for both LiCB9H10 (363 K) and NaCB9H10 (303 K). The similar conductivity behaviors with temperature for LiCB9H10 and NaCB9H10 compared to those for LiCB11H12 and NaCB11H12 , and their order-of-magnitude enhancements over disordered NaCB9H10, irrespective of structural symmetries, further reinforces the notion that anion monovalency better facilitates high cation translational mobility in these large- polyhedral-anion-based systems.