Lignin-based carbon foams and composites and related methods

Abstract

A method of making a carbon foam comprises subjecting a precursor composition comprising an amount of at least partially decomposed lignin to a first pressure for a first time, optionally, while heating the precursor composition to a first temperature; heating the compressed precursor composition to a second temperature for a second period of time while subjecting the compressed precursor composition to a second pressure to further decompose the at least partially decomposed lignin and to generate pores within the compressed precursor composition, thereby providing a porous, decomposed precursor composition; and heating the porous, decomposed precursor composition to a third temperature for a third time to carbonize, and optionally, to graphitize, the porous, decomposed precursor composition to provide the carbon foam. Also provided are the carbon foams and composites made from the carbon foams.

What is claimed is: 
     
         1 . A carbon foam comprising a carbon matrix defining a plurality of pores distributed throughout the carbon foam, the carbon foam characterized by a compressive strength of at least 20 MPa as measured from the carbon foam free of carbon-encapsulated metal nanoparticles, graphene-encapsulated metal nanoparticles, and an additive selected from carbon particles, carbon nanoparticles, metal, metal oxide, and metal carbide. 
     
     
         2 . The carbon foam of  claim 1 , wherein the compressive strength is at least 45 MPa. 
     
     
         3 . The carbon foam of  claim 1 , further characterized by a uniform distribution of pores throughout the carbon foam. 
     
     
         4 . The carbon foam of  claim 3 , further characterized by uniformly sized pores. 
     
     
         5 . The carbon foam of  claim 1 , further characterized by a porosity in a range of from 50% to 90% as measured from the carbon foam free of carbon-encapsulated metal nanoparticles, graphene-encapsulated metal nanoparticles, and an additive selected from carbon particles, carbon nanoparticles, metal, metal oxide, and metal carbide. 
     
     
         6 . The carbon foam of  claim 1 , further characterized by an apparent density in a range of from 0.1 g/cm 3  to 1 g/cm 3  as measured from the carbon foam free of carbon-encapsulated metal nanoparticles, graphene-encapsulated metal nanoparticles, and an additive selected from carbon particles, carbon nanoparticles, metal, metal oxide, and metal carbide. 
     
     
         7 . The carbon foam of  claim 1 , further characterized by a uniform distribution of pores throughout the carbon foam; uniformly sized pores; a porosity in a range of from 50% to 90%; and an apparent density in a range of from 0.1 g/cm 3  to 1 g/cm 3 , the porosity and the apparent density as measured from the carbon foam free of carbon-encapsulated metal nanoparticles, graphene-encapsulated metal nanoparticles, and an additive selected from carbon particles, carbon nanoparticles, metal, metal oxide, and metal carbide. 
     
     
         8 . The carbon foam of  claim 1 , further comprising one or more of carbon-encapsulated metal nanoparticles; graphene-encapsulated metal nanoparticles; and an additive selected from carbon particles, carbon nanoparticles, metal, metal oxide, metal carbide, and combinations thereof.