-
电化学反应过程中离子迁移、氧化还原反应的原位动态观测对研究电解池和电池充放电性能、离子迁移特性、缺陷产生和预防等具有重要意义。采用电解池模型研究电化学反应过程以方便实验参数调控,基于运动衬度 X 射线成像实验研究了其离子迁移和氧化还原反应过程。结果表明,同等条件下运动衬度 X射线成像比传统的时间减影成像的衬噪比高一个量级以上。基于运动衬度 X 射线成像成功观测到起始阶段电化学反应特性,发现电化学反应在电解池内所有位置同时发生,而不是通常理解的电场力作用下离子迁移到阴极、得到电子被还原。电极投影位置运动衬度信号强于电解液其它位置,说明电极位置氧化还原反应更密集。在通电电压低到一个临界值、传统时间减影成像很难观测到离子迁移或原子团聚的时候,运动衬度成像仍可明确揭示离子迁移(原子团簇运动)轨迹。因此,运动衬度 X 射线成像可大幅提升电解质中离子(原子)迁移的观测灵敏度,在电池、电解池电化学反应特性的原位动态研究中具有重要应用前景。The in-situ and dynamic observation of processes for ion migration and redox reactions during electrochemical reactions is critical for the understanding of the charging and discharging performance, ion migration characteristics, causes and preventives of defects in cells and electrolytic cells. For the convenience of parameter tuning, an electrolytic cell is adopted to investigate the electrochemical reaction. The processes of ion migration and redox reaction were investigated based on move contrast X-ray imaging. The experimental results demonstrated that the contrast to noise ratio of move contrast X-ray imaging is one order higher than that of the conventional temporal subtraction imaging. The initial status of the electrochemical reaction was successfully revealed by move contrast X-ray imaging. The images show that at the very beginning of the reaction the signals of move contrast distributed almost evenly in the electrolytic cell, which implicates that ion migration is initiated as soon as the cell is switched on and redox reaction occurs simultaneously all over the cell, other than that ions are driven by electric field, approach the cathode and then are reduced through electron gain. The signals of move contrast imaging are obviously stronger at positions inside the shadow of the electrodes than locations elsewhere. This means that the redox processes reacts densely at the electrodes. Adjust the electrical voltage to a critical value while the conventional methods are hard to make out ion migration or atom accumulation, move contrast X-ray imaging can still depict evidently the trace of ion migration or movement of atom clusters. In conclusion, move contrast X-ray imaging is able to improve significantly the sensitivity of observation to the trace of ions or atoms in the electrolyte and has great potentials in the in-situ investigation on the characteristics of electrochemical reactions.
-
Keywords:
- Electrochemical reactions /
- Move contrast /
- X-ray imaging /
- Ion migration
-
[1] Kang B, Ceder G 2009 Nature 458 190
[2] Okubo M, Mizuno Y, Yamada H, Kim J, Hosono E, Zhou H S, Kudo T, Honma I 2010 ACS Nano 4 741
[3] Ellis B, Perry L K, Ryan D H, Nazar L F 2006 J Am Chem. Soc 128 11416
[4] Zhao W Y, Sakurai K 2019 J Synchrotron Radiat 26 230
[5] Chen S L, Zhang Y, Zhao J J, Mi Z, Zhang J M, Cao J, Feng J C, Zhang G L, Qi J L, LI J Y, Gao P 2020 Sci Bull 65 1643
[6] Yang Y C, Gao P, Gaba S, Chang T, Pan X, Lu W 2012 Nat. Commun 3 732
[7] Warren J M, Bilheux H Z, Kang M, Voisin S 2013 Plant Soil 366 683
[8] Ilott A J, Trease N M, Grey C P, Jerschow A 2014 Nat. Commun 5 4536
[9] Zhou L, Leskes M, Liu T, Grey C P 2015 Angewandte Chemie 54 14782
[10] Zheng J, Tang M X, Hu Y-Y 2016 Angew Chem. Int. Edit 55 12538
[11] Takanashi T, Kawamura H 2019 World Congress on Medical Physics and Biomedical Engineering 2018 Prague, Czech Republic, June 3-8, 2018 p35
[12] Cheng L, Tscheuschner S, Paulus F, Hopkinson P E, Kieling J, Khler A, Vaynzof Y, Huettner S 2016 Adv Mater 28 2446
[13] Zhao W Y, Sakurai K 2017 ACS Omega 2 4363
[14] Wang F X, Zhou P T, Li K, Mamtilahun M, Tang Y H, Du G H, Deng B, Xie H L, Yang G Y, Xiao T Q 2020 IUCrJ 7 1
[15] Song X M, Pogue B W, Jiang S D, Doyley M M, Dehghani H, Tosteson T D, Paulsen K D 2004 Appl. Optics 43 1053
[16] Xie H L, Deng B, Du G H, Fu Y N, Guo H, Xue Y L, Peng G Y, Tao F, Zhang L, Xiao T Q 2020 Nucl Sci Tech 31 102
[17] Ju X L, Deng B, Li K, Yu F C, Zhang H P, Xu M W, Du G H, Xie H L, Li B, Xiao T Q 2022 Nucl Sci Tech 33 1
计量
- 文章访问数: 179
- PDF下载量: 11
- 被引次数: 0