SBIR Phase II: Liquefied Gas Electrolytes for High Energy Density Energy Storage Devices

该小型企业创新研究（SBIR）第二阶段项目的重点是使用新型液化气体电解质开发锂金属电池。虽然全球都在努力推进下一代锂电池的电解质化学，但这些努力几乎完全集中在液态和固态电解质上。相比之下，该项目旨在进一步开发一类新型电解质的用途，这些电解质使用在室温下通常为气态并在中等压力下液化的溶剂。第一阶段的工作证明了世界纪录的循环锂金属，在400次循环中平均电镀/剥离库仑效率为99.5%（每次循环0.5 mA/cm 2和0.5 mAh/cm 2），通过低温聚焦离子束表征观察到平滑和高密度的锂沉积。此外，世界纪录的低温电解质电导率为3 mS/cm在-80？C的锂基电解质，远远超过了国家的最新技术。最后，可逆的高温关闭在+40？C，由于盐沉淀的电解质电导率降低，被证明。这种高温关闭基本上消除了热失控反应的发生，使一个显着更安全的电池。通过这个NSF第二阶段赠款进一步发展这些电解质将使进一步的工作，以提高电池比能量到450瓦时/公斤，扩大工作温度从-60到+60？C，并增加了安全性，没有热失控，同时保持功率和循环寿命相当于传统的锂离子。这将通过电解质化学的进一步发展来实现，以在1000次循环中将锂金属库仑效率提高到99.8%，将高温关闭提高到+60~70 ℃。C，提高阴极性能，以更高的电压和循环寿命，以及开发高产量的研发生产线，这将提供高精度的电解质成分添加，以微调化学。&由于电解质化学可能使用几种常见的材料和制造方法，因此应该存在低成本的进入壁垒，并且预计批量生产的成本将显著降低至100美元/kWh的目标。开发的技术将特别适合低温应用，如高大气，国防和航空航天，这些应用经常承受极端温度并需要高比能量。由于与现有技术相比，在低温下具有上级性能，南8科技将首先专注于开发这些领域的技术。随着技术的成熟，最终将进入电网存储和运输市场，从而大幅减少排放和对进口燃料的依赖。这些新材料的基础化学是一个相对较新的领域，可能会导致下一代储能设备和更广泛的技术的重大进步，导致新的行业，就业增长和超越。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.