A molten Mg corrosion method for preparing porous Ti foam as self-supported Li–O₂ battery cathodes

All-metal self-supported cathodes, especially porous noble metals, are attractive alternatives for settling the issue of carbon- and binder-decomposition in Li–O₂ batteries. However, the high cost of noble metals hinders their practical application. In the present study, nanoporous Ti foam is prepared using a molten Mg corrosion method for the first time. Electron microscope images demonstrate that, nanoporous Ti foam is obtained by treating Ti-Mo alloy plates in molten Mg at 650 °C for 3 hours. Then, the foam is coated with a layer of Au nanoparticles by cool-sputtering and used as self-supported Li–O₂ battery cathodes. The nanoporous foam can decrease the consumption of gold markedly compared with traditional porous Au foam. Benefiting from the high stability, conductivity, and porosity of Ti foam, the Li–O₂ batteries exhibit good durability (cycling 118 rounds at 1C rate within a 1000 mAh g⁻¹ capacity limitation).