Journal of Applied Electrochemistry, Vol.47, No.7, 829-837, 2017
Laser structured Cu foil for high-performance lithium-ion battery anodes
To improve interface adhesion between anode film and Cu foil, ultrafast laser structuring was implemented to construct dot patterns with a variety of periodic spacing (25, 50, and 75 A mu m) on Cu foil. The microstructure and electrochemical performance of anode films coated on those structured Cu foils were characterized. It was shown that adhesive force of the electrodes increased as periodic distance between the dots on the Cu foil decreased. Comparison of XRD patterns of the wet slurries with the dried anode films showed that after drying in the case of 50 A mu m period dot structured Cu foils the most graphite particles were aligned with the c-axis, vertical to the Cu foil surface. EIS, CV, and rate capability measurements confirmed that the anode film on the 50 A mu m dot period Cu foil had the lowest impedance, strongest lithiation and de-lithiation peaks, and highest discharge capacity. The cycling test carried out under C/2 rate confirmed that the cells with the 50 A mu m dot interval Cu foil showed the highest capacity retention. We inferred that this was due to the relatively shorter diffusive path in the anode due to vertical orientation of more graphite particles against the laser structured Cu foil.
Keywords:Ultrafast laser ablation;Adhesive force;Anode films;Orientation of graphite particles;Li (+) diffusion