Optimization of the Morphology of Solid-Chitosan based Electrolyte for Zn-MnO2 Alkaline Rechargeable Batteries by Freeze Casting Method

Abstract

The ever-increasing demand for electrochemical energy storage systems across the globe has paved the way for researchers worldwide to focus on environmentally friendly batteries, with a prime focus on rechargeable Zn-MnO2 alkaline batteries. This study sheds light on the potential of the Chitosan-PVA membrane to be used as a solid, and flexible electrolyte for Zn-MnO2 batteries. It incorporates a distinct synthesis approach for the Chitosan-PVA electrolyte films, i.e., room temperature synthesis in a planetary ball mill, followed by freeze drying method at -80C to form an electrolyte film with a lamellar structure that allows it to have increased mechanical strength without compromising the flexible nature of the electrolyte. Three distinct compositions of Chitosan (600mg, 800mg, & 1000mg) were mixed with (20% & 10%) PVA to form a range of electrolyte films with different thicknesses (230 µm, 250µm, and 270µm). The obtained electrolyte films displayed varying Ionic conductivities (ICs), and Ion transference numbers (ITN) of the different swelling ratios (SR) based on the soaking time in 5M KOH. The electrolyte with 800mg of Chitosan-10%PVA, and a thickness of ~270um showed promising results in comparison with the rest of the variations in terms of the ICs and ITN, which provides a way forward for the researchers to explore the potential of this electrolyte in Zn-MnO2 rechargeable batteries.