Sodium‐Ion‐Conducting Hydrogel Material: Synthesis, Characterization and Conductivity Studies

Abstract

Herein we have reported single sodium ion conducting pseudo solid polymer electrolyte material, was synthesized successfully using sodium; 3,4,5,6‐tetrahydroxyoxane‐2‐carboxylate (ALG) and sodium salt of poly (acrylic Acid): SPA in the water as solvent via solution cast technique. This pseudo‐solid polymer material allows Na+ cation transport inside the matrix. The FTIR technique confirmed the appreciable interaction between the sodium alginate and sodium polyacrylate polymer. This amorphous polymer material has good flexibility, tensile strength, and good elasticity which provides a better electrode‐electrolyte interface. The material shows electrical conductivity in the range of 10−5 S/cm at room temperature and 10−4 S/cm at higher temperatures (>40 °C). The material shows electrochemical stability of 2.26 V owing to a very good amount of current density with ≈97 % ionic transport number for the sodium ion. The material shows drift ionic velocity in the range of 10−4 m/s and ionic mobility in the order of 10−6 m2/Vs at room temperature. It shows the matrix ionic diffusivity constant in the order of 10−7 m2/s. It possesses low activation energy for ionic movement inside the matrix of 0.465 eV. The matrix shows the correlated type of hopping. An appreciable amount of capacitance is associated with the matrix with minute electrode contribution.