CAREER: Designer Redox Active Molecules for Sustainable Electrochemical Energy Storage

在这个由化学部化学结构、动力学机制B计划资助的NSF CAREER项目中，犹他州州立大学化学与生物化学系的刘天标教授正在开发用于水性有机氧化还原液流电池（AORFBs）的低成本、可调且定义明确的氧化还原活性分子。 这些液流电池可用于低成本和更环保的能量存储。 该项目侧重于深入了解电池组件的结构和电池性能之间的关系。这些新知识为开发低成本氧化还原活性分子提供了指导，用于氧化还原液流电池作为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。 刘教授开发教育计划服务于犹他州州立大学和整个犹他州更广泛的社区。所有教育水平的学生都参与建立下一代科学家和工程师的必要人才库，以便在可再生能源存储这一至关重要的新兴领域工作。具体来说，刘教授与USU东布兰丁美洲原住民暑期导师计划（NASMP）和USU明星计划。这些计划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，并激发学术天才当地高中学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性有机氧化还原液流电池（AORFB）已被证明是非常有吸引力的能量存储。AORFB的先前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，很少有研究关注单个氧化还原活性分子的物理化学性质与其电池性能之间的相关性。该项目重点研究氧化还原活性紫精（阳极电解液）、二茂铁（阴极电解液）和2，2，6，6-四甲基-1-哌啶基氧分子（阴极电解液）的分子工程和性质研究，及其在AORFB中的电池性能。 这三类氧化还原活性分子的研究回答了以下问题：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，涉及氧化还原过程的电子数，扩散系数，电子转移速率常数，和膜渗透性？2)氧化还原活性分子的官能团如何影响其在充电和放电状态下的化学和电化学稳定性？和3）能否通过深入的机理理解开发出上级氧化还原活性分子，以实现高能量和高功率密度、长循环氧化还原液流电池？该奖项反映了NSF的法定使命，并被认为是值得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的支持。

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.