Gel Polymer Electrolyte for Aluminum-Ion Batteries

Aluminum-based batteries have potential advantages such as low flammability, low cost, and 3 electrons in the reaction that give them high charge capacity. Current research focuses on aluminum-ion batteries with carbon-derived cathodes that have achieved fast-charge capability and long-term stability; however, present some problems as: the disintegration of the cathodic material, the use of ionic liquids electrolytes, whose corrosivity, sensitivity to the environment and cost, generate safety and design problems for commercial devices. An aluminum-ion polymer battery was constructed with aluminum foil anode, graphene paper cathode, and an iongel of PMMA-AlCl3(0.68)-EMIm|AlCl4(80%) as the electrolyte, to reduce the environmental sensitivity and achieve different types of assembly. The battery was evaluated using Cyclic Voltammetry and Electrochemical Impedance Spectroscopy (EIS), finding reversible behavior between 1.5V-2.5V vs. Al (QRE) associated with the plasticizer reaction and irreversible reduction peaks between 0.5V-1.5V vs. Al (QRE) produced by the coordination of chloroaluminate cations with the polymer matrix. The battery presented a maximum coulombic efficiency of ~60%, the losses are attributed to the cathode collector corrosion and the irreversibilities in the electrodes.