Dual-phase nanostructuring as a route to flexible nanoporous metals with outstanding comprehensive mechanical properties

The mechanical properties of nanoporous metals (NPMs) are very important for their potential applications in flexible electronics. Here, the NP Cu@Zr-Cu-Al metallic glass (NP Cu@Zr-Cu-Al MG) composite with high strength, high hardness, and good flexibility is reported. The NP Cu@Zr-Cu-Al MG was synthesized by a two-step dealloying method. First, the flexible NP Zr-Cu-Al MG was prepared by selective etching the active Y-rich MG from the pseudobinary MG system (Zr47Cu46Al7 MG + Y47Cu46Al7 MG) of Cu46Zr23.5-Y23.5Al7 alloy. The NP Cu@Zr-Cu-Al MG was then obtained by further etching the NP Zr-Cu-Al MG and the Cu layer was evenly covered on the MG matrix of ligaments. The NP Cu@Zr-Cu-Al MG demonstrated good flexibility due to its non-cracking structure and the existence of flexible Zr-Cu-Al MG. Additionally, the NP Cu@Zr-Cu-Al MG showed the highest tensile strength of 143.9 MPa and nanohardness of 0.79 GPa among all the reported NPMs. The Zr-Cu-Al MG strengthening phase weakened the rupture of Cu@Zr-Cu-Al ligaments, which could effectively restrain the crack initiation and propagation in the NP Cu@Zr-Cu-Al MG. Finally, it could improve the comprehensive mechanical properties. The NP Cu@Zr-Cu-Al MG was applied as an electrode for supercapacitors and glucose biosensors. The NP Cu@Zr-Cu-Al MG electrode displayed better conductivity and supercapacitor capacitance than the bare NP Zr-Cu-Al MG electrode.