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[Display omitted] • The hydrated GO/PANI film fixed on carbon cloth is achieved via water evaporation. • Integrated rGO/PANI/CC electrode is obtained by facile hydrazine reduction. • High rGO/PANI mass loading is realized via repeating dropping/evaporating process. • The integrated electrode displays excellent capacitance and rate performance. • The all-solid-state device exhibits high energy density toward promising potentials. The convenient fabrication of supercapacitor electrodes with high active material mass loading is of great significance to the practical application. In this paper, a novel and efficient strategy is proposed to prepare graphene/polyaniline (PANI) composite with controllable mass loading towards high-performance supercapacitor electrodes. The graphene oxide (GO)/PANI colloid layer is drop-coated onto carbon cloth (CC) before evaporating most of the water. The as-obtained hydrated GO/PANI/CC film undergoes a facile hydrazine reduction treatment and yields the porous reduced GO (rGO)/PANI active layer fixed on the CC current collector, which could directly act as the binder-free supercapacitor electrode. As a result, the excellent adhesion of active layer with CC and the uniform PANI distribution on porous rGO matrix contribute greatly to the fast electron and ion transport in the electrochemical activities. The integrated rGO/PANI/CC electrode achieves a high specific capacitance of 871.5 F g−1 at the current density of 1.5 A g−1 with superior rate performance. More importantly, repeating the drop-coating/water-evaporating process could conveniently realize the high rGO/PANI mass loading (up to 10 mg cm−2) on the current collector. The corresponding symmetric all-solid-state supercapacitors with different mass loadings can deliver the maximum energy densities of 39.1 Wh kg−1, 425.3 μWh cm−2, and 4.0 mWh cm−3, manifesting their promising practical prospect. This work would provide a new path for the fabrication of graphene-based supercapacitor electrodes and other functional film materials. [ABSTRACT FROM AUTHOR]

Developing high-capacity electrode materials is critical to enhance the energy-density of lithium-ion batteries. Here, a new graphene nanoplatelets-supported SiO x -disordered carbon composite (SiO x -C/GNPs) is fabricated by a Stöber-type process and high-temperature treatment. When used as an anode for lithium-ion batteries, SiO x -C/GNPs exhibits excellent cycle stability and rate capability even under deep charge–discharge cycling. A stable reversible capacity of about 630 mAh g −1 (calculated on the total mass of the composite) can be achieved at a current density of 100 mA g −1 and the capacity retention is nearly 100% after 250 cycles. Additionally, the plateau voltages of lithium extraction for the composite are only slightly higher than those for the commercial graphite, which ensures the high energy density of the assembled batteries. The superior electrochemical performance of this novel material is due to its unique features: excellent electronic conductivity, short transportation length for both lithium ions and electrons, elastomeric space to accommodate volume changes upon Li insertion/extraction and robust connection between SiO x and GNPs. [ABSTRACT FROM AUTHOR]

A sheet-on-sheet and metal-free graphene/C 3 N 4 /carbon dots (GR/C 3 N 4 /CDots) ternary heterostructure with efficient visible-light photocatalysis for pollutants degradation has been reported. Via a convenient and hydrothermal method, large-sized GR nanosheets can serve as substrate for monodispersed dispersion of C 3 N 4 nanosheets. A subsequent loading of very small amount of CDots (1 wt%, 2–5 nm) onto sheet-on-sheet heterostructure significantly enhance visible-light-driven photoredox performances of catalysts, including oxidation of organics pollutant (RhB, 96.0%) and reduction of heavy metals [Cr(VI), 83.6%]. Excellent catalytic properties of GR/C 3 N 4 /CDots heterostructure can be predominantly ascribed to the intimate interfacial contact among constructing ingredients, increased specific surface area and enhanced light adsorption derived from GR and CDots carbon materials. Particularly, the synergistic sheet-on-sheet interaction between C 3 N 4 and carbon materials (GR and CDots) remarkably accelerate the electrons/holes separation, giving rise to significantly enhanced photoredox performances of GR/C 3 N 4 /CDots in comparison with other counterparts. The synergism effect between organic contaminants and heavy metals also contributed to the efficient performance of GR/C 3 N 4 /CDots, wherein the O 2− and OH were the main active species in the photoredox reactions. This metals-free heterostructure shows favorable photostability in cyclic experiments. We anticipate that our work could provide a classical paradigm for rational design of efficient and visible-light-driven photocatalysts for their sustainable applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

Nitrogen-doped 3D graphene frameworks (N-3D GFs) were synthesized by a facile two-step method: Polystyrene (PS) encapsulated in graphene oxide (GO) composites (denoted as PS@GO) are first synthesized, followed by a post–thermal annealing in ammonia step to get N-doped 3D GFs. The resulting N-3D GFs inherit the advantages of graphene, which possesses high electrical conductivity and high specific surface area. Furthermore, the well-defined 3D interconnected structure can facilitate the access of the electrolyte to the electrode surface, thus shortening the diffusion length of both Li + /e − , keeping the overall electrode highly conductive and active in lithium storage. Simultaneously, the in-situ formation of pyridinic N and pyrrolic N in 3D GFs provide high electronic conductivity and structure stability for lithium storage. The designed N-3D GFs electrode delivers a high specific capacity of 1094 mAhg −1 after 100 cycles at 200 mAg −1 and superior rate capability (691 mAhg −1 after 500 cycles at 1000 mAg −1 ) when used as anode for LIBs. We believe that such an inherently inexpensive, scalable, facile method can significantly increase the feasibility of building high performance energy storage system. [ABSTRACT FROM AUTHOR]

Three dye-functionalized graphene oxide/polyaniline (GAP) composites were first prepared by optimizing acid blue 74 (AB74) feed content, and then dye-functionalized graphene/polyaniline (rGAP) nanocomposites were obtained from the GAP composites through reducing and re-protonating treatments. The AB74 dye molecules with negatively charged sulfonic groups can effectively prevent aggregation of graphene sheets during the reduction process of graphene oxide, and can be used as a bridge to attach polyaniline nanorods via π–π conjunction and electrostatic attraction. Furthermore, when rGAP5 (the AB74 feed content of 5 wt.%) was used as a supercapacitor electrode material, it achieved a high specific capacitance of 579 F g −1 at a current density of 0.5 A g −1 , good cycling stability and rate capacity. [ABSTRACT FROM AUTHOR]