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Graphene oxide (GO) membranes have great potential for separation applications due to their low-friction water permeation combined with unique molecular sieving ability. However, the practical use of deposited GO membranes is limited by the inferior mechanical robustness of the membrane composite structure derived from conventional deposition methods. Here, we report a nanostructured GO membrane that possesses great permeability and mechanical robustness. This composite membrane consists of an ultrathin selective GO nanofilm (as low as 32 nm thick) and a postsynthesized macroporous support layer that exhibits excellent stability in water and under practical permeability testing. By utilizing thin-film lift off (T-FLO) to fabricate membranes with precise optimizations in both selective and support layers, unprecedented water permeability (47 L·m-2·hr-1·bar-1) and high retention (>98% of solutes with hydrated radii larger than 4.9 A) were obtained.

Single-phase metal dodecaboride solid solutions, Zr0.5Y0.5B12 and Zr0.5U0.5B12, were prepared by arc melting from pure elements. The phase purity and composition were established by powder X-ray di...

The development of highly sensitive sensors and power generators that could function efficiently in extreme temperatures and contact with fire can be lifesaving but challenging to accomplish. Herein, we report, for the first time, a fire-retardant and self-extinguishing triboelectric nanogenerator (FRTENG), which can be utilized as a motion sensor and/or power generator in occupations such as oil drilling, firefighting or working in extreme temperature environments with flammable and combustible materials. The device takes advantage of the excellent thermal properties of carbon derived from resorcinol-formaldehyde aerogel whose electrical, mechanical and triboelectric properties have been improved via the introduction of Polyacrylonitrile nanofibers and graphene oxide nanosheets. This FRTENG is not flammable even after 90 s of trying, whereas conventional triboelectric materials were entirely consumed by fire under the same conditions. The developed device shows exceptional charge transfer characteristics, leading to a potential difference up to 80 V and a current density up to 25 µA/m2. When integrated into firefighter's shoes, the FRTENG is able to discern the movements of a firefighter in hazardous situations, while providing the high thermal stability missing in conventional TENGs. The fire-retardant and self-extinguishing characteristics offered by the FRTENG makes it a path-breaking device for lifesaving wearable applications.

Three-dimensional graphenes are versatile materials for a range of electronic applications and considered among the most promising candidates for electrodes in future electric double layer capacitors (EDLCs) as they are expected to outperform commercially used activated carbon. Parameters such as electrical conductivity and active surface area are critical to the final device performance. By adding carbon nanodots to graphene oxide in the starting material for our standard laser-assisted reduction process, the structural integrity (i.e. lower defect density) of the final 3D-graphene is improved. As a result, the active surface area in the hybrid starting materials was increased by 130% and the electrical conductivity enhanced by nearly an order of magnitude compared to pure laser-reduced graphene oxide. These improved material parameters lead to enhanced device performance of the EDLC electrodes. The frequency response, i.e. the minimum phase angle and the relaxation time, were significantly improved from −82.2° and 128 ms to −84.3° and 7.6 ms, respectively. For the same devices the specific gravimetric device capacitance was increased from 110 to a maximum value of 214 F g−1 at a scan rate of 10 mV s−1.

Micro-supercapacitors (MSCs) are one of the most promising electronic circuit elements in electronic devices as they are designed for use as energy storage components, decoupling capacitors, ripple current filter elements, and in many other applications. The materials used for MSCs have been greatly restricted since only a few materials or material combinations are capable of operating at the required high frequencies with high power and sufficient stability for long-term operation [1]. By using graphene and its derivatives as electrodes, here we demonstrate that MSCs with ultrahigh power density will push further the monolithic integration and the realization of smart multifunctional autonomous system-on-a-chip.

The synthesis of graphene nanoribbons (GNRs) that contain site-specifically substituted backbone heteroatoms is one of the essential goals that must be achieved in order to control the electronic properties of these next generation organic materials. We have exploited our recently reported solid-state topochemical polymerization/cyclization-aromatization strategy to convert the simple 1,4-bis(3-pyridyl)butadiynes 3a,b into the fjord-edge nitrogen-doped graphene nanoribbon structures 1a,b (fjord-edge N2[8]GNRs). Structural assignments are confirmed by CP/MAS 13C NMR, Raman, and XPS spectroscopy. The fjord-edge N2[8]GNRs 1a,b are promising precursors for the novel backbone nitrogen-substituted N2[8]AGNRs 2a,b. Geometry and band calculations on N2[8]AGNR 2c indicate that this class of nanoribbons should have unusual bonding topology and metallicity.

We report our discovery of utilizing perhydroxylated dodecaborate clusters ([B12(OH)12]2-) as a molecular cross-linker to generate a hybrid tungsten oxide material. We further demonstrate how these robust B12-based clusters in the resulting hybrid tungsten oxide material can effectively preserve the specific capacitance up to 4000 cycles and reduce the charge transfer resistance as well as the response time compared to that of pristine tungsten oxide.

We investigated changes in the optical properties of indium tin oxide (ITO) nanocrystals as a function of temperature. ITO is a plasmonic, wide bandgap semiconductor capable of absorbing UV and IR radiation. The nanoparticles were made using a standard two-pot synthesis, which resulted in the formation of ITO nanoparticles with myristic acid and oleylamine as surface passivation ligands. Ligand exchange with (6-7% aminopropylmethylsiloxane) dimethylsiloxane-copolymer was allowed dispersion of the particles into a thermal fluid, Duratherm S, which is capable of withstanding working temperatures of 300°C. Nanoparticles suspended in the fluid were heated over a range of temperatures and the properties investigated using IR spectrometry, UV-VIS, TEM, and particle size analysis. Although heating showed no change in particle size, spectral changes were clearly observed in the form of a strong blue shift and increased absorb-ance. These temperature-dependent changes in the spectral properties of ITO were attribu...

Supercapacitors are energy storage and conversion devices that display high power. In order to increase energy density, redox-active materials can be incorporated into the carbonaceous electrode(s). Although in recent years many studies have offered different redox-active candidates and composite methods, there is a constant search for an effective, easily producible and stable composite material. Here, we present a graphene/ferrocene composition as a redox active 3-D supercapacitor electrode material. The combination of highly reversible, conductive and strongly attached ferrocene with the high surface area and open porous structure of graphene results in high-power, high-energy density supercapacitors. The graphene scaffold is converted from graphene-oxide (GO) by laser irradiation, a facile, fast and eco-friendly method. The ferrocene is chemically bonded to the graphene by two different approaches that take advantage of the strong and stable pi–pi interactions between the carbon and the aromatic ligands. The excellent bonding between the components results in low internal resistance and high reversibility of the redox reaction. The composite demonstrated a 205% increase in specific capacitance from 87 F g−1 for pure laser reduced graphene oxide to 178 F g−1 for the composite with ferrocene. This is equivalent to an energy density of 6.19 W h kg−1 while maintaining a power density of 26.0 kW kg−1.

Technological breakthroughs in energy storage are being driven by the development of next-generation supercapacitors with favorable features besides high-power density and cycling stability. In this innovation, graphene and its derived materials play an active role. Here, the research status of graphene supercapacitors is analyzed. Recent progress is outlined in graphene assembly, exfoliation, and processing techniques. In addition, electrochemical and electrical attributes that are increasingly valued in next-generation supercapacitors are highlighted along with a summary of the latest research addressing chemical modification of graphene and its derivatives for future supercapacitors. The challenges and solutions discussed in the review hopefully will shed light on the commercialization of graphene and a broader genre of 2D materials in energy storage applications.