Eco-friendly Synthesis of Nanoporous Magnesium by Air-Free Electrolytic Dealloying with Recovery of Sacrificial Elements for Energy Conversion and Storage Applications
Jintao Fu, John S. Corsi, Samuel S. Welborn, Victoria M. Basile, Lin Wang, Alexander K. Ng, Eric Detsi
Abstract
The synthesis of nanoporous Mg with minimal surface oxide coverage has been hindered by its high chemical reactivity. Herein, we demonstrate the fabrication of three-dimensional bicontinuous nanoporous Mg with ligament and pore sizes in the range of 20–30 nm using air-free electrolytic dealloying with recovery of the sacrificial material. The starting material consists of a magnesium–lithium parent alloy with lithium as the sacrificial component. During selective electrolytic leaching in an anhydrous lithium-conducting organic electrolyte solvent, the sacrificial lithium is stripped from the magnesium–lithium parent alloy used as the working electrode and plated on a pure lithium foil used as the counter electrode, enabling sacrificial element recovery, making the process eco-friendly. The morphology of the fabricated nanoporous Mg was thoroughly investigated using electron microscopy techniques, inductively coupled plasma (ICP) spectroscopy, X-ray photoelectron spectroscopy (XPS), small-angle X-ray scattering (SAXS), and X-ray diffraction. The synthesized nanoporous Mg is attractive for energy conversion and storage applications. Here, we show that it can produce hydrogen on-demand by hydrolysis with pure water and that it can also be used as a high-capacity lithium-ion battery anode.