STTR Phase I: Multifunctional Trilayer Membrane for a Stable, Scalable and Economical High Energy Capacity Li-S Battery with Long Cycle Life

The broader impact/commercial potential of this Small Business Technology Transfer (STTR) project will address concerns about the shortage of materials for Lithium-ion batteries as the number of electric vehicles increases. Lithium Sulfur (Li-S) batteries offer an opportunity because sulfur is more readily available, lower cost, and environmentally friendly. Unlike lead-acid batteries, Li-S batteries do not require use of sulfuric acid or other environmentally harmful chemicals. The global Li-S battery market will grow at an estimated annual rate of 70+% in the next 10 years, with a growth of nearly $700 M in 2018-2022. The proposed project will accelerate the development of advanced Li-S batteries. This STTR Phase I project proposes to address important technical challenges like inferior reversibility and poor safety (stability) of the Li metal anode. Equivalent circuit network (ECN) models will be developed for simulating the performance of the new Li-S cells. Accurate and appropriate models are necessary for applications of Li-S batteries. Through experiments, systems modeling, and simulation, these objectives will be accomplished: 1) Gain better understanding of Li-S electrochemistry with a new cell using an advanced membrane, 2) Study effects of different operating parameters, such as the charge and discharge rate on the cell performance, 3) Conduct preliminary studies on the effect of temperature on the Li-S cell performance, 4) Demonstrate and report high energy and long cycle performance in Li-S pouch cell, 5) Li-S cells (coin and pouch cells) will be fabricated and their performance studied at different charge/discharge rates and temperature levels using precise testing equipment. The data will be used for ECN model development and simulation studies. The potential outcome(s) of the project include development of a new Li-S pouch cell incorporating an advanced composite membrane to enable the cell to have a capacity of over 400 Wh/kg and demonstrated cycle life of over 500 cycles. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.