Fabrication of a Porous Copper Current Collector Using a Facile Chemical Etching to Alleviate Degradation of a Silicon-Dominant Li-ion Battery Anode

Abstract

In this work, we proposed a facile method to fabricate the three-dimensional porous copper current collector(3D Cu CC) for a Si-dominant anode in a Li-ion battery (LiB). The 3D Cu CC was prepared by combiningchemical etching and thermal reduction from a planar copper foil. It had a porous layer employingmicro-sized Cu balls with a large surface area. In particular, it had strengthened attachment of Si-dominantactive material on the CC compared to a planar 2D copper foil. Moreover, the increased contact areabetween a Si-dominant active material and the 3D Cu could minimize contact loss of active materials froma CC. As a result of a battery test, Si-dominant active materials on 3D Cu showed higher cyclic performanceand rate-capability than those on a conventional planar copper foil. Specifically, the Si electrodeemploying 3D Cu exhibited an areal capacity of 0.9 mAh cm-2 at the 300th cycles (@ 1.0 mA cm-2), whichwas 5.6 times higher than that on the 2D copper foil (0.16 mAh cm-2).