Heteroatom doping can effectively tailor the local structures and electronic states of intrinsic two-dimensional materials, and endow them with modified optical, electrical, and mechanical properties. Recent studies have shown the feasibility of preparing doped graphene from graphene oxide and its derivatives via some post-treatments, including solid-state and solvothermal methods, but they require reactive and harsh reagents. However, direct synthesis of various heteroatom-doped graphene in larger quantities and high purity through bottom-up methods remains challenging. Here, we report catalyst-free and solvent-free direct synthesis of graphene doped with various heteroatoms in bulk via flash Joule heating (FJH). Seven types of heteroatom-doped flash graphene (FG) are synthesized through millisecond flashing, including single-element-doped FG (boron, nitrogen, oxygen, phosphorus, sulfur), two-element-co-doped FG (boron and nitrogen), as well as three-element-co-doped FG (boron, nitrogen, and sulfur). A variety of low-cost dopants, such as elements, oxides, and organic compounds are used. The graphene quality of heteroatom-doped FG is high, and similar to intrinsic FG, the material exhibits turbostraticity, increased interlayer spacing, and superior dispersibility. Electrochemical oxygen reduction reaction of different heteroatom-doped FG is tested, and sulfur-doped FG shows the best performance. Lithium metal battery tests demonstrate that nitrogen-doped FG exhibits a smaller nucleation overpotential compared to Cu or undoped FG. The electrical energy cost for the synthesis of heteroatom-doped FG synthesis is only 1.2 to 10.7 kJ g–1, which could render the FJH method suitable for low-cost mass production of heteroatom-doped graphene.

The ever‐increasing production of commercial lithium‐ion batteries (LIBs) will result in a staggering accumulation of waste when they reach their end of life. A closed‐loop solution, with effective recycling of spent LIBs, will lessen both the environmental impacts and economic cost of their use. Presently, <5% of spent LIBs are recycled and the regeneration of graphite anodes has, unfortunately, been mostly overlooked despite the considerable cost of battery‐grade graphite. Here, an ultrafast flash recycling method to regenerate the graphite anode is developed and valuable battery metal resources are recovered. Selective Joule heating is applied for only seconds to efficiently decompose the resistive impurities. The generated inorganic salts, including lithium, cobalt, nickel, and manganese, can be easily recollected from the flashed anode waste using diluted acid, specifically 0.1 m HCl. The flash‐recycled anode preserves the graphite structure and is coated with a solid‐electrolyte‐interphase‐derived carbon shell, contributing to high initial specific capacity, superior rate performance, and cycling stability, when compared to anode materials recycled using a high‐temperature‐calcination method. Life‐cycle‐analysis relative to current graphite production and recycling methods indicate that flash recycling can significantly reduce the total energy consumption and greenhouse gas emission while turning anode recycling into an economically advantageous process.

these 1D carbon nanomaterials include carbon nanotubes (CNTs), both single-and multi-walled, as well as ribbon-and platelike carbon nanofibers, bamboo-like carbon nanotubes, cup-stacked carbon nanofibers, and many more. [7][8][9][10] 1D materials are used extensively in composites, coatings, sensors, electrochemical energy storage, and electrocatalysts, capitalizing upon their strength, conductivity, low density, broadband electromagnetic absorption, high surface area, and chemical robustness. [11][12][13][14] Due to their broad utility and scientific interest, identifying new methods of synthesizing 1D carbon materials remains critical. The majority of synthetic strategies to form 1D carbon materials, including arcdischarge, laser ablation, chemical vapor deposition, plasma torch, and high partial pressure carbon monoxide involve the mobilization of carbon atoms in feedstocks on the surface of a catalytic metal which then grow into a graphitic 1D morphology. [15] These current methods often result in mixtures of 1D materials and amorphous carbon that require separation, and 1D materials syntheses often suffer from low production rates of <1 g h −1 . [16][17][18] Some recent work has focused on converting waste plastic into higher value carbon nanomaterials, inspired by the low Graphitic 1D and hybrid nanomaterials represent a powerful solution in composite and electronic applications due to exceptional properties, but large-scale synthesis of hybrid materials has yet to be realized. Here, a rapid, scalable method to produce graphitic 1D materials from polymers using flash Joule heating (FJH) is reported. This avoids lengthy chemical vapor deposition and uses no solvent or water. The flash 1D materials (F1DM), synthesized using a variety of earth-abundant catalysts, have controllable diameters and morphologies by parameter tuning. Furthermore, the process can be modified to form hybrid materials, with F1DM bonded to turbostratic graphene. In nanocomposites, F1DM outperform commercially available carbon nanotubes. Compared to current 1D material synthetic strategies using life cycle assessment, FJH synthesis represents an 86-92% decrease in cumulative energy demand and 92-94% decrease in global-warming potential. This work suggests that FJH affords a cost-effective and sustainable route to upcycle waste plastic into valuable 1D and hybrid nanomaterials.

Flash Joule heating (FJH) is a far-from-equilibrium (FFE) processing method for converting low-value carbon-based materials to flash graphene (FG). Despite its promise in scalability and performance, attempts to explore the...

Graphene has proved to be an exceptional reinforcing additive for composites, but the high cost of its synthesis has largely prevented its addition on industrial scales. Flash Joule heating provides a rapid, bulk‐scale method for graphene synthesis from coal materials, such as metallurgical coke (MC), into metallurgical coke‐derived flash graphene (MCFG). Here, this work investigates the properties of graphene‐epoxy composites in a higher nanofiller content regime than has previously been reported in literature. Composites with 20 to 50 wt% loading of MCFG are prepared by combining MCFG with diglycidyl ether bisphenol A epoxy precursor (DGEBA) and 1,5‐diamino‐2‐methylpentane. With a 1:2 ratio of MCFG:DGEBA, the Young's modulus increases by 92% and with a 1:3 ratio, hardness increases by 140%. At a 1:4 ratio of MCFG:DGEBA, compressive strength and maximum strain increase by 145% and 61%, respectively. At a 1:3 ratio of MCFG:DGEBA, toughness increases by 496%. Finally, at a 1:1 ratio of MCFG:DGEBA, GHG emissions, water consumption, and energy consumption are reduced by 33%, 47%, and 34%, respectively. As the cost of FG plummets, since it can be produced from very low cost materials like MC, in milliseconds with no solvent or water, the prospects are promising for its high‐loading use in composites.