Al₂O₃ reinforced Nafion/Aquivion hybrid composite membranes were prepared for Li−S battery applications. Forming a hybrid composite membrane with nano-Al₂O₃ increased the electrochemical capacity. 868 mAhg⁻¹ discharge capacity and 63.8 % capacity retention were obtained at the end of 300 cycles. The properties of the Nafion/Aquivion composite membrane have been improved by utilizing nanomaterial reinforcement.

Abstract

Herein, Al₂O₃ nanofiller-reinforced lithiated Nafion:Aquivion hybrid composite ion-exchange membranes have been produced by mixing lithiated Nafion and Aquivion ionomers. After the electrochemical tests, the Li-Naf : Li-Aqu/1 : 2 compound, which offers the best electrochemical performance, was selected. Lithiated hybrid composite membranes were obtained by reinforcing Al₂O₃ nanofillers at different rates to this composition. The ion exchange capacity, polysulfide transition and solvent uptake of the obtained membranes were investigated and the structural characterizations were applied by tensile test, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and membrane morphology was examined with Field Emission Scanning Electron Microscopy (FESEM). For performing the electrochemical tests, CR2032 half cells were designed. Electrochemical characterizations of the produced membranes were carried out by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), and galvanostatic charge-discharge tests. The best electrochemical performance was achieved with 868 mAhg⁻¹ discharge capacity and 63.8 % capacity retention when Li-Naf : Li-Aqu/1 : 2 composition was reinforced with 1 % Al₂O₃ nanofiller. As a result, lithiated hybrid composite ion exchange membranes could prevent the shuttle effect of polysulfides while enabling the passing of Li ions for high-performance Li−S batteries.