Conductivity modification of gum acacia-based gel electrolytes

Gum acacia (GA) is a natural gum with a high molecular weight; it is a polysaccharide material that is acidic in nature and the least viscous among hydrocolloids. The ion-conducting behavior of water-dissolvable GA-based gel electrolytes has been studied with salt (ammonium chloride (NH4Cl)) concentration, GA content and temperature enhancement. The conductivity of GA-based gel electrolytes without salt has been found to increase with the increase in GA content at low concentrations and reaches a maximum value of 4.99 x 10(-3) S/cm at 40 wt.% of GA and then shows a small decrease at higher concentrations of GA. GA-based gel electrolytes show ionic conductivity decrements and indicate negative activation energy with increase in temperature, which contradicts the theoretical explanation - that is, sigma = sigma(o) exp(-E-a/KbT). An ionic conductivity on the order of 10(-1) S/cm has been observed for varying weights percentages of GA-based gel electrolytes containing 5 M ammonium chloride and does not show much change with temperature enhancement from 10 to 70 degrees C, which makes it suitable for their use in fuel cells and other device applications.