Turgeman Meital, Bergman Gil, Nimkar Amey, Gavriel Bar, Ballas Elad, Malchik Fyodor, Levi Mikhael D, Sharon Daniel, Shpigel Netanel, Aurbach Doron
Department of Chemistry and BINA─BIU Center for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan5290002, Israel.
Center for Physical and Chemical Methods of Research and Analysis, al-Farabi Kazakh National University, 050040Almaty, Kazakhstan.
ACS Appl Mater Interfaces. 2022 Oct 19;14(41):47066-47074. doi: 10.1021/acsami.2c13771. Epub 2022 Oct 10.
The optimal performance of organic electrodes for aqueous batteries requires their full compatibility with selected electrolyte solutions. Electrode materials having 1-3-dimensional structures of variable rigidity possess a confined space in their structure filled with water and electrolyte solutions. Depending on the rigidity and confined space geometry, insertion and extraction of ions into electrode structures are often coupled with incorporation/withdrawal of water molecules. Aside from the scientific interest in understanding the charging mechanism of such systems, co-insertion of solvent molecules affects strongly the charge storage capability of the electrodes for energy storage devices. We present herein in situ electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) investigations of polyaniline (PANI) electrodes operating in various aqueous Na-containing electrolytes, namely, NaSO, NaClO, NaBF, and NaPF. Careful analysis of the EQCM-D results provides a dynamic snapshot of the mixed anionic/protonic fluxes and the accompanying water molecules' insertion/extraction to/from the PANI electrodes. Based on our observations, it was found that the charging mechanism, as well as the capacity values, strictly depends on the electrolyte pH, the chaotropic/kosmotropic character of the anionic dopants, and the amount of the extracted water molecules. This study demonstrates the effectiveness of analysis by EQCM-D in selecting electrolytes for batteries comprising organic electrodes.
水系电池中有机电极的最佳性能要求它们与选定的电解质溶液完全兼容。具有可变刚性的1至3维结构的电极材料在其结构中具有充满水和电解质溶液的受限空间。根据刚性和受限空间的几何形状，离子向电极结构中的插入和脱出通常与水分子的嵌入/脱出相关联。除了在理解此类系统充电机制方面的科学兴趣外，溶剂分子的共插入对储能装置电极的电荷存储能力有很大影响。我们在此展示了对在各种含钠水系电解质（即NaSO、NaClO、NaBF和NaPF）中运行的聚苯胺（PANI）电极进行的带耗散监测的原位电化学石英晶体微天平（EQCM-D）研究。对EQCM-D结果的仔细分析提供了混合阴离子/质子通量以及伴随的水分子向PANI电极插入/从PANI电极脱出的动态快照。基于我们的观察，发现充电机制以及容量值严格取决于电解质的pH值、阴离子掺杂剂的离液序列高/低特征以及脱出的水分子数量。这项研究证明了EQCM-D分析在为包含有机电极的电池选择电解质方面的有效性。
