ERI: Unravel Charge Transfer Mechanisms in the Bulk and at Interphases and Interfaces of Ionogel Solid Electrolytes for High-Power-Density All-Solid-State Li Metal Batteries

这是美国国家科学基金会工程研究启动奖。使用固态电解液和锂金属负极的全固态电池以其更高的安全性和同时实现高能量、功率和寿命的潜力而闻名。离子凝胶是由离子液体限制在离子导电聚合物和/或陶瓷中形成的，它显示出与固体电解质一样的良好性能的独特组合。然而，它们可实现的功率密度和循环稳定性仍然明显较差，这主要是因为对锂离子的传输机制缺乏了解。该项目将开发一系列设计的三相离子凝胶系统，其中每一相都将进行修改，以促进锂离子的快速传输。这种机理的理解将阐明锂离子的真实传输路径和曲折，指导高性能固态电池离子凝胶基固体电解质和过渡层的结构和化学设计。此外，该项目将整合研究和教育，以促进STEM领域的跨学科学习。能量存储和转换技术的教育将提高更多的碳中和意识，并激励年轻一代探索更可持续的未来的技术解决方案。这项建议的目的是阐明三元离子凝胶固体电解质中不同亲石环境相互作用对局部锂离子传输机制的影响。亲石分子环境将通过由离子液体组成的三元离子凝胶平台(其中移动的阴离子可以与锂离子配位)、具有不同亲石基团的聚合物支架(其与锂离子弱配位以促进锂离子在聚合物相中和沿聚合物相的快速传输)以及与亲石配体接枝的陶瓷纳米膜来创造，以便于锂离子沿陶瓷相的传输。这些机理的理解将阐明a)锂离子和亲石阴离子之间的缔合和解离类型以及它们之间的竞争或协同作用；b)锂离子在不同本征界面上的真实解离和锂离子的传输，这将决定锂离子在具有不同本征界面的三元离子凝胶固体电解质中的有效传输路径和曲折；以及c)通过在陶瓷相上接枝的功能配体有效地固定阴离子来实现从双离子导电系统到单离子导电系统的转换。这些机理洞见将为通过设计有利的亲锂分子环境来调节和加速锂离子在不同界面和界面上的传输提供设计原则。这项研究具有潜在的变革性影响，可以提供关键的见解，并引导未来的研究工作朝着可扩展的生产高功率密度和高能量密度全固态电池的离子凝胶固体电解质和夹层方向发展。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This is an NSF Engineering Research Initiation award. All-solid-state batteries utilizing solid state electrolytes along with Li-metal anode are notable for their improved safety and potential to achieve simultaneously high energy, power, and longevity. Ionogels, formed by confinement of ionic liquids within ionic conductive polymers and/or ceramics, show a unique combination of favorable properties as solid electrolytes. However, their achievable power density and cycling stability remains notably inferior, owing primarily to the lack of understanding of Li-ion transport mechanisms. The project will develop a series of designed three-phase ionogel systems where each phase will be modified to promote fast Li-ion transport. The mechanistic understanding will elucidate the true Li-ion transport path and tortuosity, guiding the design of structure and chemistry of ionogel-based solid electrolytes and interlayers for high performance solid-state batteries. In addition, this project will integrate research and education for fostering interdisciplinary learnings in STEM areas. Education in Energy Storage and Conversion technology will raise more awareness of carbon neutrality and inspire younger generations to explore technical solutions for a more sustainable future.The goal of this proposal is to elucidate the local Li-ion transport mechanisms influenced by the interaction of different lithophilic environments within ternary ionogel solid electrolytes. The lithophilic molecular environments will be created through ternary ionogel platforms composed of ionic liquid where moving anions can coordinate with Li-ions, polymer scaffolds functionalized with different lithophilic groups which weakly coordinate with Li-ions for rapid Li-ion transport across and along the polymer phase, as well as ceramic nanofillers grafted with lithophilic ligands for facile Li-ion transport along the ceramic phase. These mechanistic understandings will elucidate a) the types of association and dissociation between Li cations and lithophilic anions and the competitive or cooperative interaction between them; b) the true Li-ion dissociation and Li-ion transport at different intrinsic interphases, which will determine the efficient Li-ion transport pathways and tortuosity within the ternary ionogel solid electrolyte featuring diverse intrinsic interphases; and c) the conversion from bi-ion conducting to single-ion conducting systems through effective immobilization of anions by the functional ligands grafted to the ceramic phase. The mechanistic insights will provide the design principles for regulating and accelerating Li-ion transport at various interphases and interfaces through the design of favorable lithophilic molecular environments. The research has potentially transformative impact for offering crucial insights and steering future research efforts toward scalable production of ionogel solid electrolytes and interlayers for high-power-density and high-energy-density all solid-state batteries.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.