CAREER: Designer Redox Active Molecules for Sustainable Electrochemical Energy Storage

美国犹他州立大学化学与生物化学系的刘天标教授，在美国国家科学基金CAREER项目中，为水性有机氧化还原液流电池（AORFBs）开发了低成本、可调且定义明确的氧化还原活性分子。该项目由化学学部化学结构、动力学与机制B项目资助。这些液流电池对于低成本和更环保的能源储存是有用的。该项目侧重于深入了解电池组件的结构和电池性能关系。这一新知识为开发低成本的氧化还原活性分子提供了指导，从而将氧化还原液流电池用作环保和可扩展的储能平台，从而减轻全球对化石燃料的依赖，促进我们社会的可持续发展。该项目位于有机、无机、材料和电化学的界面，因此非常适合各级科学家的教育。刘教授为犹他州立大学和犹他州更广泛的社区开发教育项目。各级教育的学生都参与到建立下一代科学家和工程师的必要人才库中来，这些科学家和工程师将在至关重要的新兴可再生能源存储领域工作。具体来说，刘教授与USU东部布兰丁印第安人夏季导师计划（NASMP）和USU明星计划合作。这些项目的重点是吸引和培训在STEM学科中代表性不足的美国本土学生，以及激发有学术天赋的当地高中生对科学的兴趣和好奇心。采用氧化还原活性有机分子的水相有机氧化还原液流电池（AORFBs）已被证明在储能方面具有很高的吸引力。先前的研究主要强调使用氧化还原活性分子的全液流电池性能。然而，很少有研究关注深入了解单个氧化还原活性分子的理化性质与其电池性能之间的关系。本项目重点研究氧化还原活性分子（阳极电解质）、二茂铁（阴极电解质）和2,2,6,6-四甲基-1-胡椒酰氧基分子（阴极电解质）的分子工程和性质及其在aorfb中的电池性能。对这三类氧化还原活性分子进行研究，以回答以下问题：1)氧化还原活性分子的分子结构如何决定其物理化学性质，包括溶解度、氧化还原电位、参与氧化还原过程的电子数、扩散系数、电子传递速率常数和膜通透性？2)氧化还原活性分子的官能团如何影响其在带电和放电状态下的化学和电化学稳定性？3)能否通过深入了解氧化还原活性分子的机理，开发出高能量、高功率密度、长循环的氧化还原液流电池？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。

In this NSF CAREER project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Tianbiao Liu of the Department of Chemistry and Biochemistry at Utah State University is developing low-cost, tunable, and well-defined redox active molecules for aqueous organic redox flow batteries (AORFBs). These flow batteries are useful for low-cost and more environmentally-friendly energy storage. The project focuses on the in-depth understanding of the structure and battery performance relationships of battery components. The new knowledge provides guidance in developing low-cost redox active molecules for the use of redox flow batteries as a environmentally-friendly and scalable energy storage platform, thus, alleviating the global reliance on fossil fuels and enhancing the sustainable development of our society. The project lies at the interface of organic, inorganic, materials, and electrochemistry, and is therefore well suited for the education of scientists at all levels. Professor Liu develops educational programs serving Utah Stat University and wider communities throughout the State of Utah. Students at all education levels participate in building the necessary talent pool of the next generation of scientists and engineers to work in the critically important and emerging field of renewable energy storage. Specifically, Professor Liu works with the USU Eastern Blanding Native American Summer Mentorship Program (NASMP) and the USU Stars Program. These programs focus on attracting and training native American students who are underrepresented in STEM disciplines and on stimulating interest and curiosity in science of academically-talented local high school students. Aqueous organic redox flow batteries (AORFBs) employing redox active organic molecules have been demonstrated to be highly attractive for energy storage. Previous studies of AORFBs have primarily emphasized full flow battery performance using redox active molecules. However, few studies have paid attention to the in-depth understanding of the correlation between physicochemical properties of individual redox active molecules and their battery performance. This project focuses on the molecular engineering and property studies of redox active viologens (anolyte), ferrocenes (catholyte) and 2,2,6,6-tetramethyl-1-piperidinyloxy molecules (catholyte), and their battery performance in AORFBs. These three classes of redox active molecules are investigated to answer the following questions: 1) How do the molecular structures of redox active molecules determine their physicochemical properties including solubility, redox potential, number of electrons involving redox processes, diffusion coefficient, electron transfer rate constants, and membrane permeability? 2) How do the functional groups of redox active molecules influence their chemical and electrochemical stabilities in both charged and discharged states? and 3) Can superior redox active molecules be developed through in-depth mechanistic understandings to enable high energy and high power densities, long cycling redox flow 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.