Polydicyclopentadiene (pDCPD), a thermoset with excellent
mechanical
properties, has enormous potential as a lightweight, tough, and stable
matrix material owing to its highly cross-linked macromolecular network.
This work describes generating pDCPD-based foams and hierarchically
porous carbons derived therefrom by combining ring-opening metathesis
polymerization (ROMP) of DCPD, high internal phase emulsions (HIPEs)
as structural templates, and subsequent carbonization. The structure
and function of the carbon foams were characterized and discussed
in detail using scanning electron, transmission electron, or atomic
force microscopy (SEM, TEM, AFM), electron energy-loss spectroscopy
(TEM-EELS), N2 sorption, and analyses of electrical conductivity
as well as mechanical properties. The resulting materials exhibited
uniform, shape-retaining shrinkage of only ∼1/3 after carbonization.
No structural failure was observed even when the pDCPD precursor foams
were heated to 1400 °C. Instead, the high porosity, void size,
and 3D interconnectivity were fully preserved, and the void diameters
could be adjusted between 87 and 2.5 μm. Moreover, foams have
a carbon content >97%, an electronic conductivity of up to 2800
S·m–1, a Young’s modulus of up to 2.1
GPa, and a
specific surface area of up to 1200 m2·g–1. Surprisingly, the pDCPD foams were carbonized into shapes other
than monoliths, such as 10’s of micron thick membranes or foamy
coatings adhered to a metal foil or grid substrate. The latter coatings
even adhere upon bending. Finally, as a use case, carbonized foams
were applied as porous cathodes for Li–O2 batteries
where the foams show a favorable combination of porosity, active surface
area, and pore size for outstanding capacity.