CAREER: Multifunctional electrolyte design and descriptors for lithium metal batteries

迫切需要加快全球范围内的脱碳努力，以支持可持续的能源经济。由于太阳能和风能等可再生能源技术的间歇性，需要储能。电池是非常有前途的，因为它们可以携带和能量密集（每质量储存的能量）。锂金属电极电池的能量存储量是目前锂离子电池的两倍，但由于缺乏合适的电解质（溶解在溶剂中的盐），尚未实现商业化。这个基础研究项目将确定相关的电解质特性，这些特性对于预测锂金属电极的行为非常重要，并利用这些见解开发新型电解质，使锂金属电池的寿命更长。该教育计划将侧重于利用与电池相关的编程活动（例如戏剧表演和电池实验）作为年度“电池日”活动的一部分，以扩大芝加哥当地和尼日利亚国际上代表性不足的少数族裔对STEM的参与和坚持。该项目的综合研究和教育计划将导致能量密集的锂金属电池，使美国更接近实现脱碳目标，扩大代表性不足的少数民族学生攻读STEM的人数，并使美国劳动力多样化和具有全球竞争力。锂金属电池具有理论上的能量密度，但锂金属沉积在高表面积的苔藓状和/或枝晶形态，这高度依赖于电解质成分。在连续循环过程中，不均匀的锂沉积和剥离会导致固体电解质间相（SEI）成分和电化学非活性（或“死”）锂的积累，导致永久性容量损失。解决锂金属挑战的一个很有希望的方法是电解质设计。然而，电解质的要求是复杂的，因为它们必须是非挥发性和不可燃的，并且具有高离子电导率，高锂转移数和高电化学稳定性。因此，物理混合物通常以爱迪生方法使用，使电解质的发展高度组合。为了解决这些电解质设计挑战，该项目将有以下目标：(1)量化电解质溶剂化特性并开发相关的电解质描述符；(2)设计一个模块化多功能电解质平台，将不同的电解质特性共价结合到单个分子中；(3)评估多功能电解质对锂金属电池的影响，并探测原位和非原位锂金属的动态变化。该研究将为定量电解质科学和广泛的电化学系统的新型电解质开辟新的道路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There is a pressing need to accelerate worldwide decarbonization efforts to support a sustainable energy economy. Due to the intermittency of renewable energy technologies such as solar and wind, energy storage is required. Batteries are highly promising because they can be portable and energy-dense (energy stored per mass). Lithium metal electrode batteries can store up to two times the energy of currently available Li-ion batteries but have not been commercialized because of the lack of suitable electrolytes (salts dissolved in solvent). This fundamental research project will determine relevant electrolyte properties that are important to predict lithium metal electrode behavior and use those insights to develop novel electrolytes that allow for lithium metal batteries that last longer. The educational plan will focus on using battery-related programming events (e.g. drama performance and battery experiments) as part of an annual “Battery Day” event to broaden the participation and persistence of underrepresented minorities in STEM both locally in Chicago and internationally in Nigeria. The project’s integrated research and educational plan will lead to energy-dense lithium metal batteries that bring the US closer to achieving decarbonization goals, expand the number of underrepresented minority students pursuing STEM, and enable a diverse and globally competitive US workforce.Lithium metal batteries have theoretical energy densities, but lithium metal deposits in a high surface area mossy and/or dendritic morphology that is highly dependent on electrolyte composition. With continuous cycling, uneven lithium deposition and stripping leads to the accumulation of solid electrolyte interphase (SEI) components and electrochemically inactive (or ‘dead’) lithium leading to permanent capacity loss. One approach with great promise to address lithium metal challenges is electrolyte design. However, electrolyte requirements are complex as they must be nonvolatile and nonflammable and have high ionic conductivity, high lithium transference number, and high electrochemical stability. Hence, physical mixtures are often used in an edisonian approach that makes electrolyte development highly combinatorial. To solve these electrolyte design challenges, this project will have the following objectives: to (1) quantify electrolyte solvation properties and develop relevant electrolyte descriptors (2) design a modular multifunctional electrolyte platform that covalently combines disparate electrolyte properties into a single molecule and (3) evaluate multifunctional electrolyte influence in lithium metal batteries and probe dynamic lithium metal changes in situ and ex situ. The research will chart a new path forward for quantitative electrolyte science and novel electrolytes for a broad range of electrochemical systems.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.