Quarternized polysulfone/ZSM-5 zeolite composite anion exchange membrane separators for aluminum-air battery

Abstract

A membrane is a critical component of an Al-air battery because it provides ion transport and ensures separation of the anode and cathode. In this work, a series of quaternized polysulfone (QPSF) membrane blended with ZSM-5 zeolite anion exchange membranes (AEMs) were fabricated by solution casting to be used as separators in Al-air batteries. All membranes showed moderate to excellent water uptake (WU), swelling ratio, ion exchange capacity (IEC), and ion conductivity measurements (IC). Incorporation of ZSM-5 zeolite resulted in hydrophilicity and improved WU, with QPSF/3 wt% ZSM-5 retaining 114% water at room temperature. The QPSF/3 wt% ZSM-5 composite membrane was the best performing membrane with the IEC and the highest hydration number of 2.85 mmol g−1, 2.23, and a maximum of IC of 229.85 mS cm−1 at room temperature, respectively. QPSF/3 wt% ZSM-5 retained 65% of its original IC in an alkaline medium after 7 days. QPSF/3 wt% ZSM-5 exhibited a stable discharge voltage of 1.3 V and a specific capacity of 11,716 mAh/gAl in a laboratory fabricated Al-air cell. This study provides an excellent anion exchange composite membrane separator candidate for Al-air battery applications.