Examination of Morphological Changes of Active Materials for Solution-Based Rechargeable Fluoride Shuttle Batteries Using In Situ Electrochemical Atomic Force Microscopy Measurements
Examination of Morphological Changes of Active Materials for Solution-Based Rechargeable Fluoride Shuttle Batteries Using In Situ Electrochemical Atomic Force Microscopy Measurements
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DOI：
10.1021/acs.chemmater.2c01751
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发表时间：
2022-09-04
影响因子：
8.6
通讯作者：
Abe, Takeshi
中科院分区：
文献类型：
--
作者：
Okazaki, Ken-ichi;Nakamoto, Hirofumi;Abe, Takeshi
使用氟阴离子作为载体的电池可能具有高容量和能量密度。特别是，氟化物穿梭电池（FSB），它使用氟离子导电液体电解质，并在室温下工作，以前已经报道，并被认为是解决全球能源和环境危机。虽然已经合成了几种电解质溶液，并且已经评估了各种活性材料的氧化/脱氧化反应，但是没有报道使用这些电解质溶液的后续FSB。在这项研究中，两种金属物种，铋和铅，这两种金属物种在由烷基氟化铵和离子液体组成的电解质溶液中具有不同的吸附/脱附机制，被用作FSB的正极和负极活性材料。通过电化学原子力显微镜（EC-AFM）原位测量，解释了反应过程中每个电极上的氧化/去氧化机制。用证据阐明了两种现有机制（直接沉积和溶解-沉积）在形态变化上的差异。此外，通过电化学原子力显微镜（EC-AFM）原位测量活性材料与电解质溶液界面的形貌变化，研究了电解质溶液中活性材料对FSB充放电过程的影响，并对FSB的循环性能和容量衰减机理进行了探讨。
Batteries using fluoride anions as the carrier might possess high capacity and energy density. Especially, the fluoride shuttle battery (FSB), which uses a fluoride-ion-conductive liquid electrolyte and operates at room temperature, has been reported previously and is deemed a solution to the global energy and environmental crises. Although several electrolyte solutions have been synthesized, and the fluorination/defluorination reactions of various active materials have been evaluated, no subsequent FSBs using those electrolyte solutions have been reported. In this study, two metal species, Bi and Pb, which have different fluorination/defluorination mechanisms in the electrolyte solution composed of alkylammonium fluoride and an ionic liquid, were used as the positive and negative active materials for the FSB. The fluorination/defluorination mechanisms at each electrode during the reactions were explained by in situ electrochemical atomic force microscopy (EC-AFM) measurements. Differences in the morphological changes by two existing mechanisms, direct fluorination and dissolution-deposition, were clarified with evidence. Furthermore, the charge/discharge process of the FSB, with the electrolyte solution combining the active materials, was demonstrated, and the cycling performance and capacity fading mechanism were discussed based on the characteristic morphological change of the active materials at their interface with the electrolyte solution obtained by in situ EC-AFM measurements.