An electrochemically roughened copper foil was evaluated as a current collector for micrometric Si powder (ball-milled) based electrodes prepared by the conventional slurry-coating method. The formation of a bunch of copper nanowires on the current collector provides a rough surface, which enhances the adhesion of the Si composite electrode as confirmed from scratch tests. This produces a major decrease of the irreversible capacity associated with the electrical disconnection of the Si particles with cycling, which results in a great improvement of the electrode cycle life. With such a roughened Cu current collector, the micrometric Si-based electrode is able to maintain a discharge capacity of 1200mAhg−1 for at least 1000 cycles.