Mg2+ ion conducting Chitosan:PVP polymer blend electrolytes for electric double layer capacitor applications

[Display omitted] •The Environmental friendly and biodegradable polymer is used to prepare electrolyte alongwith PVP/MgCl2.•The XRD and SEM analysis confirm the complexation and morphology of electrolytes.•A higher ionic conductivity of 1.9 × 10−3 S/cm is obtained for CS/PVP/MgCl2 (50:50:25 wt%) film. The ion transport study is specifically focused on enhancing Mg2+ conductivity.•The higher conducting electrolyte has low glass transition temperature.•The maximum specific conductivity Cp is 147.2 F/g for higher conducting film and this optimized film is suitable for EDLC. Biopolymer electrolytes are prepared using Chitosan (CS) and Polyvinyl pyrrolidone (PVP) incorporated with magnesium chloride (MgCl2). The complex formation of electrolytes are confirmed by X-ray diffraction(XRD) and Fourier Transform Infrared spectrometer(FTIR) analysis. The scanning electron microscope(SEM) reveals the surface morphology and microstructure of the electrolytes while energy dispersive spectroscopy(EDS) facilitates the presence of elements. The distribution of elements are confirmed with elemental mapping analysis. DSC analysis enlightens on thermal properties, offering an understanding of phase transitions and thermal stability of the films. CS/PVP/MgCl2(50:50:25) polymer electrolyte shows higher ionic conductivity value of 5.8 × 10−4 S/cm at 30 °C and the specific capacitance value of 86.5 Fg−1 at low scan rate of 10 mVs−1. Linear Sweep Voltammetry (LSV) analysis has been used to determine the electrochemical stability window of the electrolyte and it is found to be 0.7 V. This result indicates that the CS/PVP/MgCl2 electrolyte is a suitable material for energy storage device applications.