Surface Modification of Copper Current Collector to Improve the Mechanical and Electrochemical Properties of Graphite Anode in Lithium-Ion Battery

A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The BCF and MCF anodes exhibited adhesion strengths of 1.552 and 1.617 MPa, respectively. The electrochemical studies of BCF and MCF anodes showed that the initial discharge capacity of graphite anode coated on the MCF (323.6 mAh g-1) was about 8 % higher than the BCF anode (299.9 mAh g-1). The BCF anode capacity reached 227.9 mAh g-1 after 100 charge/discharge cycles at 0.5C rate, while this value was 247.7 mAh g-1 for MCF anode. The results of electrochemical impedance spectra demonstrated that the diffusion coefficient of lithium-ion for MCF anode was about 56 % higher than that for BCF anode. On the other hand, the surface modification of the copper current collector reduced the charge transfer resistance of anode from 28.5 Ω to 23.2 Ω.