Sub-micron porous niobium solid electrolytic capacitor prepared by dealloying in a metallic melt

• Sub-μm open-cell porous Nb was prepared by dealloying in metallic melt.
• Specific surface area increased with decreasing dealloying time.
• Manufactured porous Nb was applied for capacitor anode and improved capacitance.

Porous Nb was prepared by dealloying in a metallic melt. A Ni–Nb precursor was immersed in a Mg melt, and Ni was selectively dissolved into the melt. The remaining Nb self-organized into a bicontinuous structure. Removing the Mg solvent in aqueous HNO3 yielded open-cell sub-μm porous Nb, which was applied in solid electrolytic capacitors after anodization. Ligament size decreased with decreasing immersion time. This increased the mass-specific capacitance to 500,000 μFV/g, by increasing the specific surface area to 3.92 m2/g.