Macromolecules in Photovoltaics Investigation of Thermoelectric Power and Electrical Conduction Properties of Sodium Disilicate: Na ₂ Si ₂ O ₅

ABSTRACT In the temperature range of 440K to almost the solid's melting point, sodium disilicate (Na 2 Si 2 O 5 ) has been investigated for its electrical conductivity and thermoelectric power. The results have been measured as log σ T vs. T −1 plot & S vs. T −1 plot, with an emphasis on its potential as a sodium‐based superionic conductor. Temperature‐dependent electrical conductivity measurements show a notable rise, suggesting a shift to superionic behavior. The phase transition temperature ( T P ) is the term used to describe this temperature. Time‐dependent analysis of dc electrical conductivity at various fixed temperatures has been used to assess the ionic (σ i ) and electronic (σ e ) contributions to the total conductivity (σ). The activation energy for ionic conduction, Ea≈0.35 eV, reflects the mobility of sodium ions within the silicate framework. Thermoelectric power (Seebeck coefficient) studies reveal a predominantly ionic conduction mechanism, with the Seebeck coefficient showing a negative polarity, consistent with sodium‐ion transport. The interplay between the silicate network's structural dynamics and the enhanced sodium‐ion mobility at higher temperatures is examined, emphasizing the role of thermal vibrations in facilitating ion transport. These findings position Na 2 Si 2 O 5 as a promising material for solid‐state ionic devices, including sodium‐ion batteries and thermoelectric energy harvesters.