Integrated porous cobalt oxide/cobalt anode with micro- and nano-pores for lithium ion battery

An integrated porous cobalt-oxide/cobalt (Co₃O₄/CoO/Co) anode was prepared by facile processes, including directional freeze casting of a Co foam and its partial thermal oxidation to Co₃O₄/CoO, for use as a high-capacity anode material for lithium-ion batteries (LIBs). The thermal oxidation created a nanostructured oxide layer, 0.4 μm in thickness, on the surface of aligned, interconnected Co lamellae comprising the foam. In this electrode design, the Co foam was used as the current collector, and the nanowall-like Co oxide (CoO and Co₃O₄) layers acted as the anode that reacted with lithium ions during discharging and charging. The integrated porous Co₃O₄/CoO/Co anode exhibits highly reversible capacity of 989 mAh g⁻¹ after 50 cycles with an coulombic efficiency of 99.4%, which is superior to that of the conventional Co foil anode (245 mAh g⁻¹). The integrated porous Co₃O₄/CoO/Co architecture demonstrated in this study has promising potential applications for self-supporting advanced anodes with tailored macro- and microstructures for high capacity LIBs.