Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper

To incentivize carbon sequestration activities, kraft paper, a renewable and recyclable bioproduct that is already manufactured at scale, is proposed as feedstock for producing economically viable carbon materials. The paper was first additively manufactured into 3D open cell honeycombs and closed cell plate lattices using a sheet lamination process before being pyrolyzed into paper-derived architected carbon foams (PDACFs). In the isostress orientation, PDACFs displayed low moduli, high elastic strains (~ 30-40%) and a compressive resilience similar to graphene aerogels, but at stresses up to ~ 3 orders of magnitude higher, despite the brittle nature of the carbonized fibers. In the isostrain orientation, PDACFs exhibited better moduli (~ 1 MPa - 1 GPa), which were comparable to conventional carbon foams, and smaller elastic strains (~ 5-10%). Failure in isostrain orientation proceeded by fracture propagation through and/ or between the layers while cracks in the isostress orientation extended mainly across the layers. The strength of the PDACFs (~ 0.2 - 14 MPa) was similar in both orientations, however, likely because both interlayer and intralayer failure onset involved microscopic fractures initiating and propagating through a multitude of carbonized fiber interfaces. Notably, Honeycombs and Plate Simple Cubic PDACFs exhibited a combination of strength (> 3 MPa) and energy absorption (> 1 MJ/m3; > 1 kJ/kg) not found in porous carbon materials previously, suggesting that the hierarchical arrangement of carbonized fibers within a macroscopic lattice architecture is better for dissipating energy than the tetrakaidecahedron microstructure commonly found in foams. Furthermore, as an electrode in a Li-ion battery, the carbonized cellulose making up PDACFs showed reversible specific capacities of 65-140 mAh/g at a specific current of 10 mA/g for 300 cycles, which is comparable to that of commercial lithium manganese oxide batteries and graphitic anodes derived from non-renewable polymer foams.