Sodium superionic conduction in Na2B12H12

Impedance measurements indicate that Na2B12H12 exhibits dramatic Na+ conductivity (on the order of 0.1 S cm−1) above its order-disorder phase-transition at ≈529 K, rivaling that of current, solid-state, ceramic-based, Na-battery electrolytes. Superionicity may be aided by the large size, quasispherical shape, and high rotational mobility of the B12H122− anions.