Effect of three-dimensional electrode design on the capacity of CNT-based Li-ion battery anode (MWCNTs/2D Cu: MWCNTs on copper foil; MWCNTs/3D Cu: MWCNTs on copper foam; and a-Si/MWCNTs/3D Cu: amorphous Si-coated MWCNTs on copper foam). (Reprinted with permission from Kang et al. [41]. Copyright 2012 by Elsevier.)