Molecular Understanding of Ion Intercalation Processes in Rechargeable Aluminum-Carbon Batteries

美国面临的巨大挑战之一是开发新技术，改变可再生能源如何以可持续和经济的方式大规模储存。以电化学方式储存能量的可充电电池已经彻底改变了消费电子产品。对于更大规模的应用，包括电动汽车和可再生能源的电网规模存储，需要对能量密度、寿命和成本的性能进行实质性的改进。铝金属是一种潜在的理想的电池电极材料，因为它富含土壤，不易燃，无毒，成本低，每单位体积比其他普通金属可以储存更多的电荷。最近，关于由铝金属和碳电极组成的可充电电池的研究已经发表。然而，关于电池如何在碳电极内储存电荷的机制方面，人们知之甚少。该项目旨在阐明碳电极储存和释放离子和能量的基本过程，特别是在分子水平上。这些科学见解将用于设计和合成新型碳电极，从而产生具有改进储能性能的可充电铝碳电池。在教育推广方面，高中生和本科生将与大学研究人员合作，接受电化学系统的高级培训。这项研究将通过高中示威和纽约市立大学（CUNY）电视台向更广泛的受众传播，该电视台在纽约市公开播放。该项目的总体目标是在分子水平上理解可充电铝碳电池中的离子插入过程，并利用这些见解设计具有改进储能性能的新型碳电极结构。使用离子液体电解质的铝石墨电池将首先被研究，以揭示电池电解质和电极材料内部发生的化学和结构变化，这些变化是电荷状态和循环次数的函数。通过多维核磁共振（NMR）波谱、x射线衍射（XRD）、电子显微镜等技术表征嵌入碳电极的分子水平环境、离子形态和动力学以及结构。这些性质将与整体电化学性质和器件性能相关联，从而产生新的多尺度理解。替代的非腐蚀性电解质系统将被研究，这将使研究不同离子和溶剂种类的混合物如何参与和/或影响插层过程。最后，将合成基于石墨烯和碳纳米管的新型碳电极，并在铝碳电池中进行测试。特别是，局部碳结构的作用和无序对整体电化学性能的影响将被理解和控制，以产生改进的电极材料。在这项工作中提出的基本科学问题的答案将使研究人员更好地了解铝碳电池是否可以成为实用的储能系统。

One of the great challenges facing the Nation is to develop novel technologies that transform how renewable sourced energy can be sustainably and economically stored on a massive scale. Rechargeable batteries, which store energy electrochemically, have revolutionized consumer electronics. For greater scale applications including electric vehicles and grid-scale storage of renewable energy sources, substantial improvements are required for the performance properties of energy density, lifetime, and cost. Aluminum metal is a potentially ideal battery electrode material because it is earth abundant, non-flammable, non-toxic, low cost, and can store more charge per unit volume than other common metals. Recently, research on rechargeable batteries composed of aluminum metal and carbon electrodes has been published. However, mechanistic aspects of how the battery stores charge within the carbon electrodes are poorly understood. This project seeks to elucidate the fundamental processes underpinning how the carbon electrodes store and release ions and energy, particularly at the molecular level. These scientific insights will be used to design and synthesize novel carbon electrodes that will result in rechargeable aluminum-carbon batteries with improved energy storage properties. For educational outreach, high school and undergraduate students will collaborate with university researchers and receive advanced training on electrochemical systems. This research will be disseminated to a broader audience by high school demonstrations and on the City University of New York (CUNY) TV station, which is publically broadcast across New York City. The overarching objectives of this project are to understand ion intercalation processes in rechargeable aluminum-carbon batteries at the molecular level, and to use these insights to design new carbon electrode structures with improved energy storage properties. Aluminum-graphite batteries using ionic liquid electrolytes will first be studied to reveal insights into the chemical and structural changes that occur within the battery electrolyte and electrode materials as a function of state-of-charge and cycle number. The molecular-level environments, ion speciation and dynamics, and structures of intercalated carbon electrodes will be characterized by multi-dimensional nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), electron microscopy, and other techniques. These properties will be correlated with bulk electrochemical properties and device performance, yielding new multi-scale understanding. Alternative non-corrosive electrolyte systems will be investigated, which will enable studies of how mixtures of different ionic and solvent species participate and/or affect the intercalation processes. Lastly, novel carbon electrodes based on graphene and carbon nanotubes will be synthesized and tested in aluminum-carbon batteries. In particular, the role of local carbon structures and the effects of disorder on bulk electrochemical properties will be understood and controlled to yield improved electrode materials. Answers to the fundamental scientific questions posed in this work will enable researchers to better understand whether aluminum-carbon batteries could become practical energy storage systems.