Pd nanoparticles decorating flower-like Co3O4 nanowire clusters to form an efficient, carbon/binder-free cathode for Li–O2 batteries†
A novel high-performance air cathode was prepared by synthesizing Co3O4 nanowire clusters on a nickel foam (NF) substrate and then decorating these clusters with Pd nanoparticles using a pulse electrodeposition method. This carbon-free and binder-free cathode had a well-defined, flower-like morphology, presenting clusters composed of nanowires with a diameter of ∼60 nm and a length of ∼5 μm on which were located Pd particles as small as 10 nm. The new cathode exhibited excellent low polarization and superior cycling performance. We found that its enhanced electrochemical properties could be attributed to the homogeneous distribution of Pd nanoparticles on the Co3O4 nanowires, which ensured uniform growth of Li2O2 on the Pd/Co3O4/NF electrodes. This, in turn, significantly improved the cathode's OER/ORR activity and aided the formation of discharge products with uniform morphologies, as well as the decomposition of these discharge products during recharging.