Experimental and theoretical investigation of the ion conduction mechanism of tris(adiponitrile)perchloratosodium, a self-binding, melt-castable crystalline sodium electrolyte.

Sodium perchlorate (NaClO4) crystallizes with adiponitrile (ADN) as a 1:3 solvate to produce (ADN)3NaClO4, a solid electro-lyte for sodium ion conduction. The solid possesses high thermal stability (up to 150 C), ability to be melt-cast (Tm = 81 C). The pressed solid has a high ionic conductivity of 2.2 x 10^-4 Scm^-1 at room temperature with a low activation barrier for ion conduction of 22 kJmol^-1. The high conductivity is the result of low-affinity ion-conduction channels in the bulk based on the X-ray crystal structure, and by low grain boundary resistance and possibly a grain-boundary percolating network due to a flu-id-like nano-liquid-layer between the grains, observable by SEM and DSC. When the liquid nanolayer is rinsed away or re-moved by excessive drying, the bulk room temperature ionic conductivity is 4 x 10-5 Scm^-1, an activation energy for ionic con-duction for an organic solid (37 kJmol^-1), and a sodium ion transference number of 0.71. Scanning electron microscopy and classical molecular...