Casting of high surface area electrodes enabled by low-temperature welding of copper nanoporous powders and nanoparticles hybrid feedstocks

•Synthesis of spherical nanoporous copper (PCu) micron-scale powders via dealloying of Cu-Al gas-atomized precursors was demonstrated.•PCu are synthesized with high-throughput, moderate flowability, moderate-oxygen content, high-surface area and free of precipitates.•Nanoscale weldability of feedstocks composed of PCu and copper nanoparticles (CuNPs) were at temperatures as low as a third of its melting point.•Open-die casting of PCu/CuNPs resulted in parts with ultimate compression strength of 3.6 – 17.8 MPa, electrically conductive with preserved nanoporosity (i.e., pore size 24 – 36 nm).