(134e) Ionically Conductive 3D Printed Polymer Membranes As a Safe Alternative to Traditional Liquid Electrolyes in Lithium Sulfur Batteries.

The development of a safe, all solid-state lithium metal (SSLM) battery, that can rival the performance of its flammable, liquid-based electrolyte counterpart is regarded as the next step in the realm of energy storage research. Currently employed liquid solvents in commercial lithium-ion batteries across industries are toxic, polar, flammable, and present a challenge to the ever-expanding milieu of electrification of transportation. A key hurdle to overcome in order to herald SSLM batteries into mass usage is the low ionic conductivity and high interfacial resistances of solid electrolytes.

We herein present a method of surface engineering of a novel crosslinked polymer, for use as solid electrolyte for lithium sulfur batteries, through stereolithography of a mixture of acrylates, polyethene oxide, and lithium salt with appropriate pultruding topography designed to minimize impedance to ionic transfer across battery layers. To aid in conductivity, appropriate amounts of ionic liquid and silicon oxide are added to the electrolyte solution before printing the layers. Our team studied the effect of the electrolyte surface design, ionic liquid and filler content as well as curing time on the electrochemical performance of the formed membranes.

To that effect, cells were assembled with flat electrolyte layers with varying percentages of ionic liquid and silicon oxide content and their ionic conductivity gauged through impedance spectroscopy as well as electrochemical charge / discharge cycling. It was found that both ionic liquid and fillers are integral for the electrolyte membrane performance, as cells lacking either component fail all capacity tests. We asserted that cells fabricated with 3D printed electrolyte membranes in a thin layered setup can deliver a competitive impedance spectroscopy directly proportional to the presence of both ionic liquids and silicon oxide fillers.