Investigation of film solidification and binder migration during drying of Li-Ion battery anodes
Investigation of film solidification and binder migration during drying of Li-Ion battery anodes
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DOI：
10.1016/j.jpowsour.2016.04.018
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发表时间：
2016-06-30
影响因子：
9.2
通讯作者：
Schabel, Wilhelm
中科院分区：
文献类型：
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作者：
Jaiser, Stefan;Mueller, Marcus;Schabel, Wilhelm
决定电池电极微观结构的特性本质上是在干燥过程中发生变化的，这使其成为电池制造中最重要但尚未充分理解的加工步骤。功能性添加剂（例如粘合剂或炭黑）在整个薄膜中的分布很大程度上取决于干燥过程。研究了由石墨、聚合物粘合剂、炭黑和溶剂组成的代表性最先进模型系统，以深入了解基础过程。引入了一种新的实验方法，可以揭示干燥过程中整个薄膜中粘合剂浓度梯度的演变。通过能量色散 X 射线光谱 (EDS) 在顶部和底部表面检测粘合剂。研究了干燥动力学并揭示了干燥过程对电化学性能的影响。在应用高干燥速率时观察到的表面粘合剂的富集被证明取决于两个基本过程，即毛细管作用和扩散。研究结果揭示了干燥阶段的特征，为薄膜固化提供了基本的见解。在此基础上，公开了一种能够解释实验结果的自上而下的巩固机制。活性层对基材的粘附力强烈依赖于基材附近的局部粘合剂浓度。 (C) 2016 Elsevier B.V. 保留所有权利。
The property determining micro-structure of battery electrodes essentially evolves during drying, appointing it a paramount, yet insufficiently understood processing step in cell manufacturing. The distribution of functional additives such as binder or carbon black throughout the film strongly depends on the drying process. A representative state-of-the-art model system comprising graphite, polymeric binder, carbon black and solvent is investigated to gain an insight into the underlying processes. A new experimental approach is introduced that allows for revelation of the evolution of binder concentration gradients throughout the film during drying. Binder is detected by means of energy-dispersive x-ray spectroscopy (EDS) at the top and bottom surface. Drying kinetics is investigated and the impact of the drying process on electrochemical performance is disclosed. The enrichment of binder at the surface, which is observed while applying high drying rates, is shown to depend on two fundamental processes, namely capillary action and diffusion. The findings reveal characteristic drying stages that provide fundamental insights into film solidification. Based on that, a top-down consolidation mechanism capable of explaining the experimental findings is disclosed. Adhesion of the active layer to the substrate is shown to strongly depend on the local binder concentration in the vicinity of the substrate. (C) 2016 Elsevier B.V. All rights reserved.