One-Dimensional Glass Micro-Fillers in Gel Polymer Electrolytes for Li-O2 Battery Applications

Gel polymer electrolytes (GPEs) are composed of liquid electrolytes in polymer matrices and have been widely used in lithium batteries. The incorporation of fillers in electrolytes has been shown to improve Li+ transport properties due to the interaction of filler materials with the polymer, solvent, or salt. In this work, we report on the preparation of composite GPEs (cGPEs) that contain one-dimensional glass micro-fillers of approximately 1 micron in diameter and with an aspect ratio exceeding 100. The cGPEs were electrochemically characterized for Li+ transport properties and were shown to have as high as 37% improvement in ionic conductivity and 25% increase in transference number compared to GPEs, using cGPE with 1% micro-fillers. Li-oxygen batteries containing these cGPEs have also demonstrated superior charge/discharge cycling performance with as a high as 86% more cycles of 500 mAh·g−1 for cGPE-1% batteries compared to GPE batteries. Using electrochemical impedance spectroscopy, this improvement was traced to the stabilization of the interfacial resistances in the batteries owing to the improved Li+ transport properties.