3D nanoporous Ni@NiO/metallic glass sandwich electrodes without corrosion cracks for flexible supercapacitor application

Abstract

It is a great challenge to fabricate the cracks-free nanoporous metals (NPMs) for flexible supercapacitor electrodes, since the formation of corrosion cracks caused by dealloying easily results in the fracture of NPMs. This work successfully achieves the sandwich uniform nanoporous Ni@NiO core@shell electrodes containing metallic glass interlayer (np-Ni@NiO/MG) with enhanced flexibility and high electrochemical performance by controlling corrosion rates of the Ni40Zr60 MG precursors. To clarify the origin for high fragility of NPMs and improve its flexibility for wearable energy storage devices, the influence of the concentration of HF etching solution on the morphology, flexibility as well as mechanical integrity of the dealloyed Ni40Zr60 MG are investigated. It is amazingly discovered that controlling the corrosion rates of the dealloying precursors is effective in eliminating the corrosion cracks, and markedly improving the flexibility of the obtained np-Ni@NiO/MG electrodes. Moreover, as for flexible energy storage electrode, the electrochemical performance of the np-Ni@NiO/MG sandwich electrodes subjected to various bending deformation are further examined. Furthermore, a flexible all-solid-state supercapacitor (FAS) device is assembled and two FASs in series can easily light a green LED, demonstrating a highly application prospect as a wearable energy storage device.