Multi-Functional Conformal Na+ Conducting Membrane for Dendrite and Polysulfide Shuttle Suppression for Next Generation RT-Na-S Batteries

While lithium-ion (Li-ion) batteries have become ubiquitous in our day to day life, this technology is approaching its limit in terms of gravimetric and volumetric energy density. Stationary, grid-level storage of renewably energy sourced from wind and solar is driving development of next-generation battery chemistries. Stationary electrical energy storage (SEES) systems are becoming increasingly important as intermittent energy production from renewable energy sources is becoming more widespread. To achieve the adoption of large scale SEES systems at economically and environmentally sustainable levels, cost and volumetric energy density are driving the choice of battery chemistry. Giner, Inc. is developing a multi-functional membrane to advance commercial readiness and viability of room temperature sodium-sulfur (RT Na-S) battery technology. The membrane is designed to both address the technical challenges of RT Na-S technology as well provide an unmet need for a viable separator compatible with commercial scale battery fabrication. In Phase I, we developed and characterized a membrane and demonstrated performance in full Na-S small scale cells. We have demonstrated improved capacity and capacity retention, and developed a membrane which is compatible with large scale battery fabrication equipment. In Phase II, we will further develop this technology and focus on the scale up of the materials and fabrication process to demonstrate performance in prototype pouch cells. Pouch cells will be evaluated for energy density and cycle life under realistic grid-level conditions. Development of a RT Na-S battery technology for grid scale SEES applications is of enormous public benefit. Recent wide scale power outages due to an overburdened infrastructure highlight the need for technology to provide load leveling during peak power periods. As renewable energy from wind and solar becomes more widespread, SEES to store intermittent power generation for supplementing to grid power during low generation periods is key to widespread adoption of this technology. A low- cost, earth abundant solution with high volumetric energy density—such as the proposed RT Na-S battery technology—would bring the cost of energy storage to a fraction of what is currently possible and make renewable energy storage more accessible.