Hierarchically Porous Structures Prepared By Electrodeposition Onto 3D-Printed Substrates

Electrochemical energy storage devices such as batteries and supercapacitors, and chemical separation technologies such as chromatography and distillation, involve multiphase transport of chemical species, where the phases may be mobile or stationary. In these cases, a high contact area between the phases is desirable, which can be achieved through nanoscale porosity. However, transport through nanoscale pores can be slow, so a hierarchy of larger-scale pores can allow faster operation, such as more rapid charging of an energy storage device. We have combined photopolymer 3D printing, which allows creation of ordered pores on a micrometer to millimeter scale, with electroless deposition and electrodeposition of a nanoporous layer, to create millimeter-scale hierarchically porous structures. We have demonstrated that the pore network confers advantages in storage capacity and transport rates versus non-hierarchical porous structures. Our methods allow fabrication of dense structures, where the volume fractions of pore and solid are of the same order of magnitude, with spatial resolution exceeding that of 3D printing methods based on laser heating of powders or thermal extrusion of polymers. This work was supported by the Laboratory-Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2018-2643 A