The lithiation/de-lithiation behavior of Cu-nanowire/Si nano-particle composite anodes with different copper current collectors is investigated using in-situ micro Raman spectroscopy. It is revealed that not all of the active material particles experience lithiation in the first cycle. It is suggested that a portion of the anode active material is electrically disconnected from the current collector to begin with. Mapping of the connectivity of the anode electrode, performed by in-situ micro-Raman revealed that the portion of the disconnected material depends on the type of the current collector and on the active material loading. The disconnected zones are distributed unevenly over the electrode area. (C) 2015 Published by Elsevier B.V.