Reinvestigation of the ionic conductivity of a layered Li(BH3NH2BH2NH2BH3) salt

Abstract

We reinvestigated the ionic conductivity of lithium ions for Li(BH₃NH₂BH₂NH₂BH₃), an ammonia borane derivative. The observed conductivity (4.0 × 10⁻⁶ S cm⁻¹ at 65 °C) was found to be over four orders of magnitude higher than the value reported previously at 70 °C for this compound. Since very slow thermal decomposition of Li(BH₃NH₂BH₂NH₂BH₃) progresses already below 100 °C, the previous results reported for 70–130 °C most likely correspond to decomposed samples. The activation energy for the lithium conductivity of polycrystalline layered Li(BH₃NH₂BH₂NH₂BH₃) (57 kJ mol⁻¹) resembles that of powdered Li₃N (59 kJ mol⁻¹), suggesting a similar mechanism of lithium diffusion in both materials.