Double Paddle‐Wheel Enhanced Sodium Ion Conduction in an Antiperovskite Solid Electrolyte

Antiperovskite structure compounds (X3AB, where X is an alkali cation and A B are anions) have the potential for highly correlated motion between a cluster anion on or site. This so-called “paddle-wheel” mechanism may be basis enhanced mobility in solid electrolytes. Through combined experiments modeling, first instance of double paddle-wheel mechanism, leading to fast sodium ion conduction antiperovskite Na3−xO1−x(NH2)x(BH4), shown. As concentration amide (NH2−) anions increased, large positive deviations ionic conductivity above that predicted from vacancy diffusion model observed. Using electrochemical impedance spectroscopy, powder X-ray diffraction, synchrotron neutron ab initio molecular dynamics simulations, NMR, rotational characterized it found influenced by rotation both NH2− BH4− species, resulting factor 102 higher at x = 1 than expected alone. Generalization this phenomenon other could accelerate conductor exploration design.