LAUSR

DOI: 10.1002/aenm.201702545 various important applications, especially in energy conversion/storage due to their large surface area, good electrical conductivity, great physicochemical stability, and high surface reactivity.[1–9] In these carbons, 2D materials, such as graphene, have drawn much more attention because their low-dimension structure could shorten ion-diffusion length and realize fast electron transfer in an electrochemical reaction process. Extensive efforts have been devoted to controllably exfoliate graphite into 2D carbon materials.[10–13] ACs have been broadly used for various application over the past years due to their low cost, high specific surface area, and rich porous structure, but their conductivity and ratio of surface to weight are still not comparable with graphene.[14–16] ACs are normally derived from various carbon-rich organic precursors by carbonization at high temperatures following by different activation process such as treatments with KOH, ZnCl2, and H3PO4. ACs can have high porosity, large specific surface area (≈2000 m2 g−1) and excellent adsorption capacity through different activation processes; however, the currently used carbonrich organic precursors are easily to result in large aggregates and end-died pores at high temperature carbonization for poor accessibility of reactants and/or ions, low conductivity, and low utilization in energy storage devices.[22,23] Post-treatment of carbon materials can punch pores only on the surface of bulk carbon and is hard to destroy chemical forces between aggregated layers for separation. Graphene-like lamellar nanomaterials can have inherent advantages of high ratio of surface area to weight, high exposure surface atoms, and fast charge transport behavior. The space and channels between the lamellar layers can greatly boost ions or/and reactants accessibility and significantly shorten the diffusion length to an electrode. It is also very meaningful to convert biomass into valuable carbons,[24–26] in particular for “waste-to-wealth” purpose. Chemical modification for biomass is much easier than that for carbon materials. Moreover, chemical modification and biomass carbonization will induce heteroatoms into carbon materials to tailor the carbon electron-donor properties, the electrical and chemical behaviors of carbons. Active carbons have unique physicochemical properties, but their conductivities and surface to weight ratios are much poorer than graphene. A unique and facile method is innovated to chemically process biomass by “drilling” holes with H2O2 and exfoliating into graphene-like nanosheets with HAc, followed by carbonization at a high temperature for highly graphitized activated carbon with greatly enhanced porosity, unique pore structure, high conductivity, and large surface area. This graphene-like carbon exhibits extremely high specific capacitance (340 F g−1 at 0.5 A g−1) and high specific energy density (23.33 to 16.67 W h kg−1) with excellent rate capability and long cycling stability (remains 98% after 10 000 cycles), which is much superior to all reported carbons including graphene. Synthesis mechanism for deriving biomass into porous graphene-like carbons is discussed in detail. The enhancement mechanism for the porous graphene-like carbon electrode reveals that rationally designed mesoand macropores are very critical in porous electrode performance, which can network micropores for diffusion freeways, high conductivity, and high utilization. This work has universal significance in producing highly porous and conductive carbons from biomass including biowastes for various energy storage/conversion applications.