Department of Chemical Engineering, The City College of New York, CUNY, 160 Convent Ave., New York, NY 10031, USA.
Department of Chemical Engineering, The City College of New York, CUNY, 160 Convent Ave., New York, NY 10031, USA.
J Magn Reson. 2023 Mar;348:107374. doi: 10.1016/j.jmr.2023.107374. Epub 2023 Jan 9.
Rechargeable aluminum-organic batteries are composed of earth-abundant, sustainable electrode materials while the molecular structures of the organic molecules can be controlled to tune their electrochemical properties. Aluminum metal batteries typically use electrolytes based on chloroaluminate ionic liquids or deep eutectic solvents that are comprised of polyatomic aluminum-containing species. Quinone-based organic electrodes store charge when chloroaluminous cations (AlCl) charge compensate their electrochemically reduced carbonyl groups, even when such cations are not natively present in the electrolyte. However, how ion speciation in the electrolyte affects the ion charge storage mechanism, and resultant battery performance, is not well understood. Here, we couple solid-state NMR spectroscopy with electrochemical and computational methods to show for the first time that electrolyte-dependent ion speciation significantly alters the molecular-level environments of the charge-compensating cations, which in turn influences battery properties. Using 1,5-dichloroanthraquinone (DCQ) for the first time as an organic electrode material, we utilize solid-state dipolar-mediated and multiple-quantum NMR experiments to elucidate distinct aluminum coordination environments upon discharge that depend significantly on electrolyte speciation. We relate DFT-calculated NMR parameters to experimentally determined quantities, revealing insights into their origins. The results establish that electrolyte ion speciation impacts the local environments of charge-compensating chloroaluminous cations and is a crucial design parameter for rechargeable aluminum-quinone batteries.
可充电铝有机电池由丰富的、可持续的电极材料组成，而有机分子的分子结构可以被控制，以调整它们的电化学性能。铝金属电池通常使用基于氯铝酸盐离子液体或深共熔溶剂的电解质，这些电解质由多原子含铝物种组成。当氯铝阳离子（AlCl）为其电化学还原的羰基基团充电补偿时，基于醌的有机电极储存电荷，即使在电解质中没有天然存在这样的阳离子。然而，电解质中的离子形态如何影响离子电荷存储机制以及由此产生的电池性能，还不是很清楚。在这里，我们首次结合固态 NMR 光谱学、电化学和计算方法表明，电解质依赖性离子形态显著改变了电荷补偿阳离子的分子水平环境，进而影响电池性能。我们首次使用 1,5-二氯蒽醌（DCQ）作为有机电极材料，利用固态偶极介导和多量子 NMR 实验阐明了放电时显著依赖于电解质形态的不同铝配位环境。我们将 DFT 计算的 NMR 参数与实验确定的数量相关联，揭示了其起源的见解。结果表明，电解质离子形态影响电荷补偿的氯铝阳离子的局部环境，是可充电铝醌电池的一个关键设计参数。
