Structural, electrical, and electrochemical properties of PVA-based biodegradable gel polymer electrolyte membranes for Mg-ion battery applications

Ionic liquid-doped biodegradable gel polymer electrolyte membranes are currently new opportunities for rechargeable magnesium-ion batteries. In this work, poly(vinyl alcohol)/magnesium trifluoromethanesulfonate/1-ethyl-3-methylimidazolium trifluoromethanesulfonate (PVA/Mg(Tf)(2)/EMITf) membranes of different compositions are prepared by solution casting. The crystalline structure, morphology, ionic conductivity, electrochemical stability window, and thermal stability of the membranes are analyzed by various techniques. It is found that the pristine PVA membrane possesses a semi-crystalline structure and its degree of crystallinity declines with augmenting EMITf concentration. The room-temperature ion conductivity of the 85PVA:15Mg(Tf)(2):15EMITf gel polymer electrolyte membrane exhibits a high value of 2.10 x 10(-4) S cm(-1). Meanwhile, this gel polymer electrolyte membrane shows a wide electrochemical stability window (similar to 5 V) and the temperature dependence of ionic conductivity obeys the Arrhenius rule (E (a) = 0.25 eV). Additionally, the mechanical properties of the electrolyte membrane are sufficiently high for its applications, being the following values: Young's modulus = 33 MPa; breaking strain = 452%; yield strength = 4.8 MPa. This inexpensive and environment-friendly gel polymer electrolyte membrane could be a promising potential electrolyte material for Mg-ion battery applications. PVA-based biodegradable gel polymer electrolyte membranes are developed. The optimal membrane has a high room-temperature conductivity of 2.10 x 10(-4) S cm(-1). The temperature dependence of ionic conductivity obeys the Arrhenius rule. The membrane exhibits a wide electrochemical stability window (similar to 5 V). The mechanical properties of the membrane are high enough for applications.