表面技术2025，Vol.54Issue(10)：1-12,12.DOI:10.16490/j.cnki.issn.1001-3660.2025.10.001
锂电复合集流体用磁控溅射Cu籽晶层微观结构及性能调控
Microstructure and Performance Regulation of Cu Seed Layer by Magnetron Sputtering for Composite Current Collector Used in Lithium Battery
摘要
Abstract
In this work,nanoscale Cu seed layers were deposited on PP substrates by DC magnetron sputtering technique,aiming to solve the conductivity and bonding issues of composite Cu foils applied in current collectors for lithium-ion batteries.Cu films with low resistivity and favorable adhesion performance were obtained by regulating process parameters such as substrate temperature,gas flow,sputtering power,etc.The surface morphology of Cu films was analyzed by field emission scanning electron microscope(FESEM).The four point probe meter was employed to test the film square resistance,and the resistivity was subsequently calculated.The adhesion strength was qualitatively assessed based on the cross-cut test method.With the increase of the substrate temperature,the grain sizes of the films increased,followed by the decrease of the film resistivity as well as adhesion strength.As the gas flow increased,the deposition rate initially increased and then decreased.Under low-pressure conditions,black spots appeared on the film surface.EDS analysis indicated that these black spots were not surface oxides,but rather the result of the film being too thin and incomplete island-to-island connectivity.The resistivity showed a trend of initially decreasing and then increasing,which was attributed to the presence of these microscopic defects that enhanced electron scattering within the film.Therefore,copper films deposited under low-pressure conditions typically exhibited higher resistivity,while the adhesion strength between the film and the substrate gradually improved.As the sputtering power(1,1.5,2,and 2.5 kW)increased,the deposition rate of the film significantly increased.The XRD results for the 2.5 kW showed only a weak Cu(111)diffraction peak,indicating that the Cu(111)plane with the lowest surface energy,preferentially grew during the early stages of film formation.At sputtering powers of 1 kW and 1.5 kW,micro-pores and cracks appeared on the surfaces of Cu films deposited on Si and PP substrates,respectively.By adjusting the deposition time for the 1 kW and 1.5 kW samples,the surface became smooth when the film thickness reached approximately 80 nm,and the observed micro-pores or cracks were attributed to insufficient film thickness.A comparison of the cross-hatch test results for Cu films of the same thickness but under different sputtering powers revealed that as the power increased,the adhesion strength between the film and the substrate decreased.Based on the microstructure,electrical and bonding properties of Cu seed layers,the optimal deposition parameters were found as follows:substrate temperature of-15℃,gas flow(pressure)of 400 mL/min(0.24 Pa),sputtering power of 1.5 kW,and Cu thickness of approximately 80 nm.Under the above deposition conditions,the Cu film exhibited a dense microstructure,and the resistivity was as low as 9.72×10-8 Ω·m.Besides,the bonding strength was rated as level 1.The microstructure and properties of Cu films were significantly affected by the substrate temperature,gas flow as well as sputtering power.Hence,the Cu seed layers for composite current collectors could be obtained by regulating deposition process with excellent performance.关键词
复合集流体/磁控溅射/Cu籽晶层/电学性能/结合力Key words
composite current collectors/magnetron sputtering/Cu seed layer/electrical properties/adhesion分类
矿业与冶金引用本文复制引用
张柳燕,郝晓瑜,汪洋,杨英,古红涛,储松潮,武俊伟,郑军..锂电复合集流体用磁控溅射Cu籽晶层微观结构及性能调控[J].表面技术,2025,54(10):1-12,12.基金项目
安徽省重点研究和开发计划(202304a05020084)Key Research and Development Program of Anhui Province(202304a05020084) （202304a05020084）
