SBIR-STTR Award

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.

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The broader impact/commercial potential of this Small Business Technology Transfer Research (STTR) project includes reducing the US dependence on foreign-sourced materials for the production and supply of battery systems. There are increased concerns about the shortage of materials for lithium ion batteries (LIB) as the number of electric vehicles increases. Lithium Sulfur (Li-S) batteries use sulfur which is more readily available, lower cost, and environment-friendly. Li-S batteries do not require the use of sulfuric acid or other more harmful chemicals, which allows them to be disposed of easily or recycled. This project will advance knowledge in addressing challenges to the development of practical and commercially viable (Li-S) batteries. The Global Lithium-Sulfur (Li-S) Battery Market was valued at $696 Million in 2019 and is anticipated to reach $6,686 Million by 2028, with a CAGR of 29.6% during the forecast period. Li-S batteries are mainly used in aviation, automotive, electronic device, and power & energy sector due to the growing demand for environmentally friendly energy with higher energy density than other battery types. Li-S technology has potential to enhance safer battery manufacturing in the US.This STTR Phase II project proposes to address important technical challenges against the development of practical Li-S batteries. These challenges include limited cycle life, high self-discharge rates and over-heating at end of charge. These are thought to be caused by the shuttle, where cathode species diffuse to the anode and react directly with the metallic lithium. A system approach will be employed to develop practical high performance Li-S Cells by focusing on: Performance (high energy density, large temperature range, and considerable cycle life); safety; and manufacturability. The project combines experimental and electrochemical modeling approaches to achieve a Li-S cell with 400-600 Wh/kg; ?200 cycles; - 20oC to 60oC @ 1C. The project will use advanced trilayer multifunctional separator and lithium metal anode to solve the problems associated with the shuttling effect. Simulation tools will be used to study and optimize the design and performance of the Li-S cells. The technical objectives for Phase 2 include the design, fabrication and characterization of progressively larger pouch cells (from 50 mAh to 500 mAh/1000 mAh). The development path will focus on achieving high energy density Li-S cells first and increasing the temperature range at a reasonable number of 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.