Fabrication of 3D-Printed Carbon Microarchitected Structures with High Yield from Polyacrylonitrile Composites via Gel Infusion and Pyrolysis

Abstract

Fabrication of geometrically complex conductive carbon electrodes with micrometer-scale features via polymer 3D printing and pyrolysis enables precise control over precursor composition and structure geometry, enabling the development of a tunable electrode design space for electrochemical systems. Continuous liquid interface production 3D printing of lattices with high surface-to-volume ratios offers promise for producing polymer pyrolysis precursors with tailored microarchitected structures. Herein, a method is reported for 3D printing of polyacrylonitrile-derived carbon structures via gel infusion and subsequent pyrolysis. With optimized pyrolysis conditions, samples demonstrate high char yields of greater than 40% by mass, comparable to yields for conventionally electrospun polyacrylonitrile fibers and higher than commercial resin alternatives. Characterization of polyacrylonitrile-derived 3D carbon lattices reveals carbon crystallite sizes in the nanocrystalline to amorphous regime and capacitance values up to 1.98 F/g corresponding to an electrochemically active surface area (ECSA) of >1 m²/g with solid lattice beams. Increasing the pyrolysis temperature results in a higher ECSA, likely caused by increased surface roughness confirmed by microscopy. This gel infusion and pyrolysis method establishes a platform for incorporation of high char yield linear polymers into high-resolution microarchitected structures, paving a pathway for producing hierarchical 3D electrodes for energy storage, catalysis, and reactor technology applications.