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.