Bicontinuous Mesoporous Metal Foams with Enhanced Conductivity and Tunable Pore Size and Porosity via Electrodeposition for Electrochemical and Thermal Systems

Abstract

Mesoporous metals are used in applications requiring high specific surface area and fast mass transport in an electrically conductive network and are primarily produced via dealloying. However, dealloyed metals retain a residual concentration of the sacrificial component, and the final composition of the porous metal is coupled to the same process controls that determine pore size and porosity. The residual component can significantly impact salient physical properties and is a critical contributor to the resistivity of many dealloyed films. To circumvent the impurities introduced by dealloying, we employ block copolymer films as templates to produce three-dimensional bicontinuous films of high-purity electrodeposited nickel and gold. We use this technique to demonstrate decoupling of stoichiometry, pore size, and porosity of mesoporous metals and demonstrate reduced resistivity due to improved material purity. We report electrical resistivity measurements of the films, with nickel and gold exhibiting resistivities of 3.9 × 10–7–6.2 × 10–7 and 2.2 × 10–7–2.4 × 10–7 Ω·m, respectively. The resistivities of the mesoporous metal are substantially lower than many reported values for dealloyed films and close to values predicted by effective medium theory. This work demonstrates a scalable, low-cost, robust platform to prepare mesoporous metals with low resistivity, including myriad electrochemical and thermal systems.