Two-level porosity electrodes from metal-polymer dispersions

Abstract

Provision of large electrode surface areas is key to achieve process intensification in electrochemical processes. While commonly used porous electrode materials such as metal foams can provide increased surface areas, the 3D design is limited to flat electrodes which are prone to mass transport limitations. Here, we show a novel fabrication method for mechanically stable porous nickel electrodes from metal-polymer dispersions. These dispersions enable 3D shaping of the electrodes and therefore the control of the mass transport inside the reactor. The demonstrated addition of pore forming agents to the polymer solution facilitates the targeted hierarchical design of the pore size distribution to yield maximum porosity while maintaining mechanical stability. To compare the specific surface area of the different materials, planar electrodes were produced from nickel-polymer dispersions and their electrochemical surface area (ECSA) was deduced from cyclic voltammetry (CV) measurements. Finally, we demonstrate that our hierarchically porous nickel electrodes with two levels of porosity show an ECSA of 2.4 × 106 m2/m3, which is a 125-fold increase with respect to a commercial nickel foam (19.2 × 103 m2/m3). These metal-polymer dispersions facilitate the fabrication of novel 3D-structured free-form fabricated electrodes for well defined fluid flow conditions, enabling mass transfer control inside the reactor’s flow channel.

Keywords

• Metal-polymer dispersions
• Porogens
• Hierarchical porosity design
• Electrochemical surface area
• Electrochemistry
• Electrodes