Conducting Biopolymer Composite Electrolyte Films: Synthesis and Characterization

The synthesis of a pectin biopolymer and ionic salt (KI)-incorporated biopolymer composite electrolyte system is reported in this communication for electrochemical device fabrication. The solution cast technique is used to create composite electrolyte films of synthesized pectin biopolymer with KI salt at different concentrations. The conductivity achieved for the pectin biopolymer-based electrolyte films is up to the order of 8.1 × 10⁻⁶ S/cm, which is an increase of three orders over the conductivity (2.7 × 10⁻⁹ S/cm) of pure pectin. Electrical, structural, and optical studies of the biopolymer electrolyte films are carried out and described. The optical properties are represented by polarized optical microscopy images which show the amorphous nature of the electrolytes films. The electrochemical stability window (ESW) presents a potential window of 1.82 V, which makes the electrolyte film suitable for device fabrication. The maximum cationic transference number reveals the ionic nature of the biopolymer electrolyte films.