Building a Better Battery: Ionic Conductivity of Granular Hydrate Crystals

Although solid state batteries are an alternative to conventional batteries, they generally produce low power due to their poor ionic conductivity. This study tested the ionic conductivities of powdered potassium sodium tartrate and potassium aluminum sulfate, two double salts that have garnered attention as potential solid state electrolytes. The substances were hypothesized on having abnormally high conductivities. Conductivity was measured using electrical impedance spectroscopy on an Arduino UNO. The results indicated that the double salts had indeed high conductivities for an ionic crystal at 5.6e-5±6e-6 S/m for PST and 7.8e-6±9e-7 S/m for PAS. However, the other 3 materials tested all produced similar values. Furthermore, one of the materials tested, sodium chloride, has a documented conductivity of 10-12 S/m. The high conductivities as well as the discrepancy between the measured and documented conductivities of sodium chloride were attributed to the powder form of the materials. Caking may have occurred and increased conductivity by increasing defect concentration as well as by creating moisture channels through which free ions could flow. These results have vast implications if a powdered electrolyte material may be successfully applied to existing fast ion conductors instead of insulators such as sodium chloride