The carbon net negative conversion of biochar, the byproduct of pyrolysis bio-oil production from biomass, to very high-purity (99.95%), highly crystalline flake graphite that is essentially indistinguishable from high-grade commercial Li-ion grade graphite, is reported. The flake size of the graphite is determined by the physical dimensions of the metal particles imbedded in the biochar, demonstrated in the range of micrometers to millimeters. “Potato”-shaped agglomerates of graphite flakes result when the flake diameter is in the 1–5 μm range. The process is shown to work with a variety of biomass, including raw lignocellulose (sawdust, wood flour, and corn cob) and biomass components (cellulose and lignin), as well as lignite. The synthesis is extremely rapid and energy efficient (0.25 kg/kWh); the graphite is produced with a very high yield (95.7%), and the energy content of its coproduct, bio-oil, exceeds that needed to power the process. The demonstrated process is a tremendous advance in the sustainability of graphite production, currently commercially mined or synthesized with very high environmental impacts, and results in a value-added product that could economically advantage carbon-neutral bio-oil production.

Since being developed over 50 years ago, aromatic polyamides have been used industrially for numerous highperformance applications due to their heat resistance, chemical stability, and high strength. Despite this extensive time span, limited applications as surface coatings have been explored due to most aromatic polyamides being insoluble in organic solvents and their extremely high melting temperatures. However, new polymerization techniques have been developed to overcome this insolubility, allowing applications such as reverse osmosis membranes and gas separation membranes to be developed. With the recent advancement of substituent effect chain-growth condensation polymerization, controlled growth aromatic polyamides have been shown to grow from flat and curved surfaces. In this study, aromatic polyamides with a protecting side chain were grown from flat and curved surfaces to allow for post polymerization deprotection and the introduction of hydrogen bonding along the backbone of the polyamide. The aromatic polyamide brushes formed were then characterized using transmission electron microscope and atomic force microscopy to explore important physical properties of the polymer brushes, including grafting density and Young's modulus. The introduction of hydrogen bonding dramatically increased the Young's modulus of the aromatic polyamide brushes from 5−6 to 22−32 GPa. Our results demonstrate the tunability of the aromatic polyamide brushes to achieve high mechanical strength and pave the way for their application in areas such as high-performance coatings.

The carbon net negative conversion of bio-char, the low value byproduct of pyrolysis bio-oil production from biomass, to high value, very high purity, highly crystalline flake graphite agglomerates with rationally designed shape and size tailored for lithium-ion battery energy storage material is reported. The process is highly efficient, 0.41 g/Wh; the energy content of its co-product of the process, bio-oil, exceeds that needed to power the process. It is shown that the shape of the starting material is retained during the transformation, allowing the ultimate morphology of the graphite agglomerates to be engineered from relatively malleable biomass. In contrast to commercial graphite production, the process can be performed at small scale with low equipment costs, enabling individual research laboratories to produce Li-ion grade graphite with customizable shape, size and porosity for Si/graphite composite and other graphite involved anodes. The mechanism of the graphitization of bio-char, a “non-graphitizable” carbon, is explored, suggesting the molten metal catalyst is absorbed into the pore structure, transported through and transforming the largely immobile biochar. Finally, the transformation of biomass to rationally designed graphite morphologies with Li-ion anode performance that closely mimic commercial shaped graphite is demonstrated.

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In the field of printed electronics, there is a pressing need for printable resistors, particularly ones where the resistance can be varied without changing the size of the resistor. This work presents ink synthesis and printing results for variable resistance, inkjet-printed patterns of a novel and sustainable carbon nanomaterial—multilayer graphene nanoshells. Dispersed multilayer graphene nanospheres are sterically stabilized by a surfactant (Triton X100), and no post-process is required to achieve the resistive functionality. A surface tension-based adsorption analysis technique is used to determine the optimal surfactant dosage, and a geometric model explains the conformation of adsorbed surfactant molecules. The energetic interparticle potentials between approaching particles are modeled to assess and compare the stability of sterically and electrostatically stabilized multilayer graphene nanoshells. The multilayer graphene nanoshell inks presented here show a promising new pathway toward sustainable and practical printed resistors that achieve variable resistances within a constant areal footprint without post-processing.