Novel massif-like CuxO nanostructure was directly growing on Cu foam via a facile thermal oxidation method in air atmosphere. The massifs are about 5 mu m in mean diameter and 4 gm in mean height, which consist of a large number of nanoparticles with mean size about 100 nm. CuxO nanowires that evolve from the particles locate at the laps of the massifs. Galvanostatic battery testing shows that the CuxO/Cu electrode exhibits excellent cycle stability and rate capability. The charge and discharge capacities are both 1.8 mAh cm(-2) after 100 cycles under a discharge/charge rate of 0.35 C. After testing at various rates from 0.2 to 12 C over 50 cycles, the 5th-cycle discharge capacity can resume well when lowering the discharge/charge rate to 0.2 C. The performances are testified due to a novel electrochemical activation effect that induces the reconstruction of porous forest-like morphology in cycling. (C) 2013 Elsevier Ltd. All rights reserved.