Preparation, micro-structure and characterization of high strength and low profile lithium copper foil with SPS and HP additives

Abstract

Copper foil is an important negative current collector material for lithium ion battery. Its mechanical properties and appropriate roughness have an important influence on the negative electrode and battery performance. Adding additives to the plating solution is an effective means to improve the performance of lithium copper foil. Here we prepared Cu-(SPS + HP) copper foil with a tensile strength of 570.57 MPa, elongation of 4.47%, and roughness of 0.812 μm. Moreover, the optical contact angle test shows that Cu-(SPS + HP) has the best surface wettability (the highest surface energy 50.62 mN/m). XRD and EBSD tests show that the fundamental reason for improving the mechanical properties of Cu-(SPS + HP) is the preferred orientation of the crystal plane (220) and the phenomenon of large grains including small grains. Besides, the electrochemical test of Cu-(SPS + HP) bath is conducted to determine the principle of additives in the plating process, cathodic reaction characteristics and electrocrystallization nucleation mechanism. Finally, we establish the electrodeposition model. The reaction behavior of SPS and HP in the plating process synergistically promoted the preparation of excellent performance lithium copper foil.