Experimental investigation into battery electrode surfaces: The distribution of liquid at the surface and the emptying of pores during drying.
Experimental investigation into battery electrode surfaces: The distribution of liquid at the surface and the emptying of pores during drying.
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DOI：
10.1016/j.jcis.2017.01.063
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发表时间：
2017-05
影响因子：
9.9
通讯作者：
S. Jaiser;L. Funk;M. Baunach;P. Scharfer;W. Schabel
中科院分区：
文献类型：
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作者：
S. Jaiser;L. Funk;M. Baunach;P. Scharfer;W. Schabel
干燥是生产细颗粒薄膜的关键步骤，因为复杂的微观结构发展和功能添加剂在整个薄膜中重新分布，从而塑造了薄膜的性能。随着毛细管液体运输的出现，孔隙排空的开始构成了薄膜形成过程中的一个重要标志。以锂离子电池阳极为例，采用一种新颖的实验方法研究了薄膜的收缩、表面液体含量的变化和表面孔隙中液体的耗竭。光学增白剂被纳入薄膜中，薄膜在对流狭口干燥器中产生。经过不同的干燥时间，在暴露于UV-A辐射期间发出荧光的薄膜图像被捕获并通过图像处理进行分析。用激光位移传感器观察薄膜收缩。发现第一个孔隙一空，孔隙流体就开始对流输送。通过在薄膜上施加外力，即压力波动，揭示了从完全饱和到部分清空的薄膜的转变。研究了干燥速率和颗粒形状的意义。我们表明，表面孔隙中的液体耗竭可以发生在薄膜收缩结束之前或同时发生。
HypothesisDrying constitutes a key step in the production of thin, particulate films as the complex microstructure develops and functional additives redistribute throughout the film, thus shaping the film properties. The onset of pore emptying constitutes a paramount marker in the film formation process as capillary liquid transport emerges.ExperimentsFilm shrinkage, development of surface liquid content and liquid depletion in surface pores of thin films are studied by means of a novel experimental approach, using the example of lithium-ion battery anodes. An optical brightener is incorporated into the films, which are produced in a convective slot-nozzle dryer. After various drying times, images of the film, which emit light fluorescently during exposure to UV-A radiation, are captured and analyzed by image processing. Film shrinkage is observed by means of a laser displacement sensor.FindingsAs soon as the first pores empty, pore fluid is transported convectively. By exerting an external force, i.e. a pressure surge, on the film, the transition from a fully saturated to a partially emptied film is revealed. The significance of drying rate and particle shape are studied. We show that liquid depletion in surface pores can occur both prior and concurrent with the end of film shrinkage.