Additive manufacturing of composite porosity mixer electrodes

[Display omitted] •We present a scalable method for selective laser sintered 3D porous electrodes.•Functional domains of the electrode are created with varying porosity.•The intrinsic porosity is determined by global printing parameters.•Due to the mixer geometry, the electrodes facilitate passive mixing.•A progressive facilitation of the pore space is shown for rising Re numbers. Electrochemical reactors present a viable means to unleash the full potential of renewable energies. With maximized surface areas, and thus increased reaction rates, the elimination of diffusion boundary layers on the electrode surface becomes increasingly important, calling for 3D structured electrodes that provide mass transport control inside the reactor. We produce 3D structured stainless steel mixer electrodes with high surface areas from selective laser sintering. By global control of the laser power, electrodes are rendered intrinsically porous without the need to define micro-features. The result is a composite porosity electrode (CPE) with a highly porous skin, a rigid porous support and a dense current collector core. The CPE shows increasing reaction rate of the porous surface with intensifying passive mixing at rising Reynolds numbers. This is explained by a large electrochemical surface area of the porous electrode that is made accessible through the mixer electrode’s mass transport enhancement. With its excellent scalability, this method promises great potential for the process intensification of a wide range of electrochemical applications.