Magnesium chloride-infused chitosan-poly(vinyl alcohol) electrolyte films: A versatile solution for energy storage devices

The potential of advanced energy storage devices lies in using solid biodegradable polymer electrolytes. This study is focused on a solid blend polymer electrolyte (SBPE) film based on chitosan (CS)–poly(vinyl alcohol) (PVA) blend matrix doped with magnesium chloride (MgCl₂) salt via solution casting. The interaction of MgCl₂ was verified via X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The SBPE with 30 wt% MgCl₂ exhibited the highest ionic conductivity of 1.24 × 10⁻⁶ S cm⁻¹ and an ionic transference number of 0.92. Thermogravimetric analysis (TGA) revealed thermal stability up to 220 °C, and the electrolyte showed favorable electrochemical stability at 3.09 V, as revealed by the I-V analysis. The sample's cyclic voltammetry (CV) curve with the highest conductivity showed distinct oxidation and reduction peaks. The discharge performance of Mg|(CS + PVA+ MgCl₂)|Cathode cell with different combinations of cathode materials illustrated the potential of the SBPE for use in magnesium-ion batteries. The CV response indicated non-faradaic behavior for the fabricated supercapacitor, with a specific capacitance of 5.80 F g⁻¹ at 5 mV s⁻¹. The non-flammable electrolyte ensures safe use in battery applications, presenting a sustainable, biodegradable, and cost-effective solution for advanced energy storage systems.