3D highly oriented metal foam: a competitive self-supporting anode for high-performance lithium-ion batteries

To develop good rate capability and good cycle stability electrode, hierarchical porous coral-like ZnO/ZnCo2O4/Co3O4 coating was fabricated on a novel 3D straight-through layered copper current collector with one-step solution combustion method and used as self-supporting anode for lithium-ion batteries (LIBs). The coral-like ZnO/ZnCo2O4/Co3O4 coating facilitated the full penetration of the electrolyte and increased the activation rate of the active material. Also, the novel 3D copper current collector has an increased surface area compared to a traditional foam metal, providing an optimal structure for balancing the volume-change tolerance and the energy density of the porous electrode. In addition, the highly oriented structure favors the effective transport of electrons and Li ions within the 3D electrode. As a consequence, high reversible capacity of 1428 mAh g−1 at a current density of 200 mA g−1 after 100 cycles and excellent rate capability of 682 mAh g−1 at 1000 mA g−1 were achieved. This study provides a facile and scalable path toward high-performance self-supporting electrodes for LIBs and demonstrates that the volume density of self-supporting electrodes can be enhanced by increasing surface area of the 3D structured current collector.