A new type of core shell nanocapsules with Ni nanoparticles as cores and amorphous CuO as shells have been synthesized through the arc-discharge method and subsequently annealing process. Amorphous CuO nanoshells lead to the improved stability and electrochemical performances. When evaluated as anode materials for lithium-ion batteries, the Ni/amorphous CuO nanocapsules deliver an initial discharge capacity of 1238.4 mAh g(-1) at 100 mA g(-1) and maintain a higher reversible capacity of 673.4 mAh g(-1) over 100 cycles, compared to the Ni/crystalline CuO nanocapsules (392 mAh g(-1)). The feasibility of this material in lithium-ion batteries will offer guidelines for the future design of new materials with optimum properties and beneficial structural elements to realize improvements in electrochemical performances. (C) 2013 Elsevier B.V. All rights reserved.