SBIR-STTR Award

This STTR Phase I project is focused on improving the energy density, safety and ultra-low temperature capability of battery devices. Conventional batteries fall short of these critical requirements for next-generation electric vehicle technologies, which are necessary to reduce emissions and the nation?s reliance on fossil fuel imports. Although the eventual goal of the proposed technology is to enter automotive markets, it may have an equally strong impact for applications in other areas requiring energy storage at low-temperatures. For example, multiple efforts aim to enable high-atmosphere telecommunications to further global connectivity to the internet, particularly in remote locations of the globe in third world countries whose standard of living could be enhanced with greater communication and education. Further, the proposed chemistry could also potentially be useful in electrochemical deposition of difficult to plate metals such as titanium or silicon for use in the aerospace, medical or high tech industries, areas which will ensure the U.S. remains internationally competitive while increasing job opportunity and tax revenue from emerging technologies. It is also a priority of this STTR to coordinate with the partner research institution to providing training and internship opportunities to graduate and undergraduate students from underrepresented communities in this research work to further improve our national industry by training the next generation workforce to better be prepared for industry and higher-education.This project aims to develop a novel electrolyte chemistry for next generation energy storage devices which has potential to address these three critical areas (energy density, safety, wide temperature operation). While conventional electrolyte chemistry commonly uses solvent solutions which are typically liquid at room temperature, this project will explore the use of solvent solutions which are gaseous at room temperature and liquefied under moderate pressures. Preliminary work on this novel electrolyte chemistry has shown high performance at ultra-low temperatures, enabling many high-atmosphere and aerospace applications without need for additional thermal management and engineering. In addition, a reversible battery shut-down mechanism at high temperatures, inherent in the electrolyte chemistry, allow for strong mitigation of thermal runaway for improved battery safety. Finally, high potential for a substantial increase in energy density with use of next-generation electrode materials has been shown to be possible. The focus of this project will be to develop these novel electrolytes and demonstrate superior performance in a full cell device with application to the automotive industry and low-temperature markets. The underlying fundamental chemistry with these new materials is a relatively new field and it is hoped these materials will lead to advances in next-generation energy storage devices and other technologies, leading to new industries, job growth and beyond.

This Small Business Innovation Research (SBIR) Phase II project is focused on the development of a lithium metal battery using a novel Liquefied Gas Electrolyte. While there is an intense global effort to advance electrolyte chemistry for next-generation lithium batteries, these efforts focus almost entirely on liquid and solid-state electrolytes. In contrast, this project aims to further develop the use of a novel class of electrolytes which use solvents that are typically gaseous at room temperature and liquefied under moderate pressures. Phase I work demonstrated world-record cycling lithium metal with an average plating/stripping coulombic efficiency of >99.5% over 400 cycles with (0.5 mA/cm2 and 0.5 mAh/cm2 each cycle) with smooth and highly dense lithium deposition as observed through cryogenic focused-ion-beam characterization. Further, a world-record low temperature electrolytic conductivity of 3 mS/cm at -80 ?C for lithium-based electrolytes was obtained, far exceeding the state-of-art. Lastly, a reversible high temperature shut-down at +40 ?C, due to a decrease in electrolyte conductivity from salt precipitation, was demonstrated. This high temperature shut-down essentially eliminates thermal runaway reaction from occurring, making for a significantly safer battery.Further development of these electrolytes through this NSF Phase II grant will enable further work to increase battery specific energy to 450 Wh/kg, expand operating temperatures from -60 to +60 ?C, and increased safety with no thermal runaway while maintaining power and cycle life comparable to conventional Li-ion. This will be accomplished with further development of the electrolyte chemistry to improve lithium metal coulombic efficiency to >99.8% over 1000 cycles, increase the high temperature shut-down to +60~70 ?C, increasing cathode performance to higher voltages and cycle life, and the development of a high throughput R&D line which will offer high precision addition of electrolyte components to fine tune the chemistry. Because the electrolyte chemistry may use several common materials and manufacturing methods, there should be low cost barrier to entry and it is expected there will be significant cost reduction in volume production down to the goal of $100/kWh. The developed technology will be especially well suited for low temperature applications such as high-atmosphere, defense, and aerospace which frequently endure extreme temperatures and require high specific energy. Because of the superior performance at low temperatures compared to the incumbent, South 8 Technologies will first focus on developing the technology in these areas. As the technology matures, an eventual move into grid storage and transportation markets will follow, leading to a substantial decrease in emissions and reliance on imported fuels. The underlying fundamental chemistry with these new materials is a relatively new field and may potentially lead to significant advances in next-generation energy storage devices and broader technologies, leading to new industries, job growth and beyond.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.