Application of Scanning Electron Microscopy in Electrolytic Copper Foils
The characterization of copper foil morphology by scanning electron microscopy can help researchers and developers to optimize and improve the preparation process and performance of copper foils to further meet the existing and future quality requirements of high-performance lithium-ion batteries. Wide Range of Copper Applications Copper metal is widely used in lithium-ion batteries and printed circuit boards because of its ductility, high conductivity, ease of processing and low price. Depending on the production process, copper foil can be categorized into calendered copper foil and electrolytic copper foil. Calendered copper foil is made of copper blocks rolled repeatedly, with high purity, low roughness and high mechanical properties, but at a higher cost. Electrolytic copper foil, on the other hand, has the advantage of low cost and is the mainstream copper foil product in the market at present. The specific process of electrolytic copper foil is (1) dissolving copper: dissolve raw copper to form sulfuric acid-copper sulfate electrolyte, and remove impurities through multiple filtration to improve the purity of the electrolyte. (2) Raw foil preparation: usually polished pure titanium rolls as the cathode, through electrodeposition of copper ions in the electrolyte is reduced to the surface of the cathode to form a certain thickness of copper layer. (3) Surface treatment: the raw foil is peeled off from the cathode roll, and then after post-treatment, the finished electrolytic copper foil can be obtained. Figure 1 Electrolytic Copper Foil Production Process Copper Metal in Lithium-ion Batteries Lithium-ion batteries are mainly composed of active materials (cathode material, anode material), diaphragm, electrolyte and conductive collector. Positive potential is high, copper is easy to be oxidized at higher potentials, so copper foil is often used as the anode collector of lithium-ion batteries. The tensile strength, elongation and other properties of copper foil directly affect the performance of lithium-ion batteries. At present, lithium-ion batteries are mainly developed towards the trend of "light and thin", so the performance of electrolytic copper foil also puts forward higher requirements such as ultra-thin, high tensile strength and high elongation. How to effectively improve the electrolytic copper foil process to enhance the mechanical properties of copper foil is the main research direction of copper foil in the future. Suitable additive formulation in the foil making process is the most effective means to regulate the performance of electrolytic copper foil, and qualitative and quantitative research on the effect of additives on the surface morphology and physical properties of electrolytic copper foil has been a research hotspot for scholars at home and abroad. In materials science, the microstructure determines its mechanical properties, and the use of scanning electron microscopy to characterize the changes in the surface micro-m...
