SupportingInformationCarbonAerogelEvolution:Allotrope,Graphene-Inspired,and3D-PrintedAerogelsSwetha Chandrasekaran, Patrick G. Campbell, Theodore F. Baumann, Marcus A.Worsley*Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California,UnitedStates94551*correspondingauthor:worsley1@llnl.gov

Figure S1. Citations per year for a) carbon aerogel and b) graphene aerogelpublications.

FigureS2.SEMimagesofCNTfoamscontaininga)30wt%andb)55wt%CNTsandTEMimagesc)andd)atdifferentmagnificationsofafoamcontaining30wt%CNT.ReproducedbypermissionfromRef.43(AmericanInstituteofPhysics).

FigureS3.SEMmicrographsofa,b)CA,d)CAwith13wt%CNT,andf,h,i)CAwith41wt%CNT.TEMmicrographsofthecolloidalcarboncorrespondingtoc)CAandCAwith13wt%CNT,ande,g)ofthefibrillarcarboncorrespondingtoCAwith13and41wt%CNT.ReproducedbypermissionfromRef.48(WileyandSons).

FigureS4.RepresentationofreactionschemeforcrosslinkingCNTs.ReproducedbypermissionfromRef.50(RoyalSocietyofChemistry)..

Figure S5. Picture of MWCNT/CHI monoliths with different shapes and sizesresultingfromtheISISAprocessingofMWCNT/CHIsuspensionsplacedindifferentdisposablecontainers;aninsulinsyringe(left)andapolystyrenecuvette(right)(a)(baris1cm).SEMmicrographofthelongitudinalsectionofaMWCNT/CHImonolith(b)(baris50mm).TheMWCNTcontentofeverymonolithshowninthefigureis85wt%.Arrowsindicatethedirectionoffreezing.ReproducedbypermissionfromRef.53(AmericanChemicalSociety).

FigureS6.(a)PhotographsoftheproductspreparedbyhydrothermalreductionofGOdispersionswithdifferentGOconcentrationsat180°Cfor12h;(b)photographsoftheproductspreparedbyhydrothermalreductionof2mgmL-1ofGOat180°Cfordifferenttimes.ReproducedbypermissionRef.71(AmericanChemicalSociety).

FigureS7.(a)13Cand(b)1HNMRspectraforGOpowder,GOafterinitialgelation,andGA.ReproducedbypermissionfromRef.83(RoyalSocietyofChemistry).

FigureS8.(a)SchemeillustratingthesynthesisprocessofGAfromtheassemblyofGOatoil-waterinterfaceandthesubsequentchemicalreduction.(b)WholeviewoftheGAderivedfromtheemulsionwithGOconcentrationof2.00mg/mL,revealingthat the bulk of aerogel is entirely composed of cellular-like pores. (c) The imageshows theclosely linkedporeswithpolyhedralmorphology. (d)Ahexagonalporesharestheboundarywithothersixadjacentpores,ensuringthefirmbridgeofthe

connection. (e) The ultrathin andwrinkledwall. Reproduced by permission fromRef.93(NaturePublishingGroup).

FigureS9.(a)TGAcurves fortheGAtreatedat1050,1500,2000,and2500°C.(b)Oxidation temperature, TO, of GA vs annealing temperature. (c) Young's modulusand energy loss for GA vs annealing temperature. (d) Bulk density and electricalconductivityofGAvsannealingtemperature.ReproducedbypermissionfromRef.100(AmericanChemicalSociety).

Figure S10. Macroscopic and Microscopic structures of CNT/GAs. (a) Digitalphotograph of CNT/GAs with diverse shapes. (b) A 100 cm3 CNT/GA cylinderstandingona flower-likedog’s tail (Setairaviridis (L.)Beauv). (c)A∼1000cm3CNT/GAcylinder(21cmindiameterand3cminthickness).(d-e)Microscopicallyporous architecture of a CNT/GA at differentmagnifications, showingCNT-coatedgraphenecellwalls.(f-h)SEMimagesofdifferentinterconnectionsforCNTs-coatedgraphene(graphene@CNTs)cellwalls:overlapping(f), twisting (g),andwrapping(h). (i) Cartoonof a flattenedCNT-coatedgraphene cellwall. (j-l) Cartoonmodelscorresponding to the three interconnectionstyles shown in (f-g) respectively.Thegray lamellar, orangewires andbrownwires represent the graphene sheet, CNTscoatedonthetopandCNTscoatedonthebackofthegraphenesheet,respectively.(m,n) TEM images of CNT-coated graphene cellwalls, theHRTEM image of a cellwalledge(insetin(m),scalebaris2nm)andtheSAEDpatterns(insetin(n))takenat the labeled area. (o) Schematic illustration of idealized building cells of ourCNT/GAmadeby synergisticassemblyofgrapheneandCNTs. (p)SEM imageandphotograph(inset in (p))of the lightestneatgrapheneaerogel (ρ=0.16mgcm-3,i.e.,1.38mgin8.6cm3).ReproducedbypermissionfromRef.103(WileyandSons)..

Figure S11.a Macroscopic visualization, showing that nanotube aerogels collapseand graphene-coated aerogels recover their original shape after compression by≥90%.b,σversusεcurvesfornanotubeaerogelsalongtheloadingdirectionandforgraphene-coatedaerogelsduringloading–unloadingcycles.Thehysteresisincreasesat largerε for thegraphene-coatedaerogels. Insets:photographsof aerogels aftergraphene coating at ε=0% (left) and 60% (right). c,d, Fatigue resistance ofgraphene-coated nanotube aerogel at 60% strain, 1Hz, for the 1st and 2,000thcycles(c)andat2%strain,100Hz,forthe1stand106thcycles(d).ReproducedbypermissionfromRef.39(NaturePublishingGroup).

Figure S12. Fabrication scheme for CNT/GA via microwave irradiation (MWI).ReproducedbypermissionfromRef.106(AmericanChemicalSociety).

FigureS13.Transmissionelectronmicrographsofamorphouscarbonprecursorandrecovered diamond aerogel. (A and B) Bright-field transmission electronmicrographs of amorphous aerogel (A) and recovered aerogel (B). Samples aresupported on lacy carbon. Scale bars: 200 nm. (C and D) Corresponding electrondiffraction from precursor and recoveredmaterial, respectively. (In D thefundamental beam is blocked.) (E and F) High resolution images of carbon anddiamond aerogel microstructure. Nanocrystalline lattice fringes visible in F(arrowheads)correspondtothe(111)planeofcubicdiamondwithalatticespacingof 2.06 Å. Scale bars: 5 nm. Reproduced by permission from Ref. 10 (Copyright(2011)NationalAcademyofSciences).

Figure S14. Growth process of Aerographite. a) Photograph of utilized ZnOtemplateswithavolumeof1.77cm3.b-d)SEMmicrographsshowingtwoexamplesforthestructuralvarietyofZnOcrystaltemplates,herewithacorrugatedsurface.e)Photograph of an intermediate state of a sample on its way from ZnO toAerographite.f-h)SEMrevealingtemplateremovalandformationofcarbonlayers.ReproducedbypermissionfromRef.109(WileyandSons).

Figure S15. TEM images of original GA (a,c) and converted BN aerogel (b,d). Thelower-magnification TEM images (a,b) show that both aerogels are porous withfeaturesizesofabout30nm.Thehigher-magnificationTEMimages(c,d)showthatthe aerogels comprise layered structures, indicated by the parallel, dark fringes.UponconversiontoBN,thelayeredstructuresbecomemorecrystallinewithsharptransitions between the facets (d), compared to the more meandering layers

observedintheGAs(c).Inaddition,theaveragenumberofwallfortheconstituentsheetsincreasesfrom2to3inthecaseoftheGAsto6to8fortheBNaerogels.Scalebars are 200 nm (a,c) and 10 nm (c,d). Reproduced by permission from Ref. 17(AmericanChemicalSociety).

FigureS16.Characterizationof3DGO/BPNFaerogelwith13.4wt%BPcontent:(a)homogeneous aqueous solution containing BPNFs, GO nanosheet and D400. (b)Aluminium foil covered reaction vessel. (c) Gelation of GO and BPNFs forming ahydrogel.(d)MacroscopicviewofGO/BPNFaerogelafterfreeze-dryingtreatment.Field emission scanning electronmicroscopy (FE-SEM) imagesof neatGOaerogel(e–f) and GO/BPNF aerogel (g–h), respectively. X-ray photoelectron spectroscopy(XPS)curveofbulkBP(i),neatGOaerogelandGO/BPNFaerogel(j), respectively.ReproducedbypermissionfromRef.125(RoyalSocietyofChemistry).

FigureS17.TheGA3Dprintingprocess.a)3Dprintingsetup.b)3Dprintingoficesupport. c)3DprintingofGO suspension.d) Immersingprinted ice structure intoliquidnitrogen.e)Freezedrying.f)Thermallyreducedto3DultralightGAoncatkin.g)3DGAarchitecture, left:2.5structureandright:3Darchitecturewithoverhangstructures.h)GAswithvariouswallthickness.ReproducedbypermissionfromRef.148(WileyandSons).