Proton conducting polymer electrolyte based on plasticized chitosan–PEO blend and application in electrochemical devices

• Addition of EC enhanced the conductivity up to (2.06 ± 0.39) × 10−3 S cm−1.
• The highest conducting sample obeyed QMT model.
• Proton batteries deliver a maximum power density up to (9.73 ± 0.75) mW cm−2.
• The discharge capacitance and specific capacity of the EDLC increases with increasing number of charge–discharge cycle.

Plasticized chitosan–poly(ethylene oxide) (PEO) doped with ammonium nitrate (NH4NO3) electrolyte films are prepared by the solution cast technique. From Fourier transform infrared (FTIR) spectroscopy analysis, hydroxyl band of pure chitosan film is shifted from 3354 to 3425 cm−1 when blended with PEO. On addition of 40 wt.% NH4NO3, new peaks at 3207 cm−1 and 3104 cm−1 appear in the hydroxyl band region, indicating the polymer-salt complexation. The carboxamide and amine bands are observed to shift to 1632 and 1527 cm−1, respectively. The interaction of chitosan–PEO–NH4NO3–EC can be observed by the appearance of the doublet CO stretching band of EC. The sample with 70 wt.% ethylene carbonate (EC) exhibits the highest room temperature conductivity of (2.06 ± 0.39) × 10−3 S cm−1. This result is further verified by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) studies. Proton battery is fabricated and shows an open circuit potential (OCP) of (1.66 ± 0.02) V and average discharge capacity at (48.0 ± 5.0) mA h. The maximum power density of the fabricated cell is (9.73 ± 0.75) mW cm−2. The polymer electrolyte is also employed as separator in electrical double layer capacitor (EDLC) and is cycled for 140 times at room temperature.