Uniquely arranged graphene-on-graphene structure as a binder-free anode for high-performance lithium-ion batteries.

3D graphene interconnected frameworks homogeneously connected with a few-layer graphene film (3DG/FLG) constitute a novel hierarchical hybrid structure for anodes in lithium-ion batteries. The pore-rich 3D graphene network is favorable for Li(+) diffusion and electron transport, and the FLG is a non-metallic current collector that effectively collects/transports charge carriers from/to the 3D graphene network and provides an excellent scaffold to support the 3DG.

3D graphene-Fe3O4 nanocomposites with high-performance microwave absorption.

3D Fe3O4-graphene nanocomposites were conveniently prepared via a direct hydrothermal grafting method. On the basis of the unique properties of both single-crystalline Fe3O4 and 3D chemically reduced graphene oxide, with characteristics such as ultralow density and high surface area, the as-prepared graphene-Fe3O4 nanocomposites showed high-performance microwave absorption ability and have the potential for application as advanced microwave absorbers.

Graphene microtubings: controlled fabrication and site-specific functionalization.

Manipulating graphene through engineering for macroscopic assemblies of practical importance is a big challenge. We develop a dually geometric confinement approach for the scalable preparation of meter-long graphene microtubings (µGTs) with a tunable diameter. They have strength comparable to graphene fiber and can be shaped to hierarchical multichannel µGT systems in a straightforward way. Of particular importance, µGTs can be selectively functionalized in a site-specific outer-wall, inner-wall, outer/inner-wall, and within-wall fashion, which endows the µGTs with unique properties for desirable applications. Apart from the magnetically and photoelectronically responsive µGTs developed here, a self-powered micromotor made of Pt inner-wall modified µGT showing agile motion in aqueous medium has been also achieved. Beyond the applications demonstrated in this study, the well-defined µGT systems can also play essential role in other important fields such as fluidics, catalysis, purification, separation, and sensing.

A linear graphene edge nanoelectrode.

A nanometer-thick linear graphene edge nanoelectrode was constructed based on the edge plane of chemical vapor deposition (CVD) grown few-layer graphene, which showed much better electrochemical performance compared with traditional carbon fibre microelectrodes.

Functional graphene springs for responsive actuation.

A new type of graphene fiber spring (GFS) has been demonstrated to possess a large elongation of up to 480% with a stable elasticity coefficient for 100,000 times of stretch. Remarkably, the GFS performs reversibly stretchable actuation under electrostatic effects, and responds to an applied magnetic field for the development of novel magnetostriction switches and actuators once functionalized with magnetic nanocomponents.

Moisture-activated torsional graphene-fiber motor.

A new type of moisture-driven rotational motor is developed using a helical arrangement of graphene sheets along a graphene oxide fiber, which not only presents remarkable performance as a reversible rotary motor with a rotary speed of up to about 5200 revolutions per minute under humidity alternation, but also allows the construction of humidity switches and promising moisture-triggered electric generators.

Monolithic graphene fibers for solid-phase microextraction.

Monolithic graphene fibers for solid-phase microextraction (SPME) were fabricated through a dimensionally confined hydrothermal strategy and their extraction performance was evaluated. For the fiber fabrication, a glass pipeline was innovatively used as a hydrothermal reactor instead of a Teflon-lined autoclave. Compared with conventional methods for SPME fibers, the proposed strategy can fabricate a uniform graphene fiber as long as several meters or more at a time. Coupled to capillary gas chromatography (GC), the monolithic graphene fibers in a direct-immersion (DI) mode achieved higher extraction efficiencies for aromatics than those for n-alkanes, especially for polycyclic aromatic hydrocarbons (PAHs), thanks to π-π stacking interaction and hydrophobic effect. Additionally, the fibers exhibited excellent durability and can be repetitively used more than 160 times without significant loss of extraction performance. As a result, an optimum extraction condition of 40°C for 50min with 20% NaCl (w/w) was finally used for SPME of PAHs in aqueous samples. For the determination of PAHs in water samples, the proposed DI-SPME-GC method exhibited linear range of 0.05-200µg/L, limits of detection (LOD) of 4.0-50ng/L, relative standard deviation (RSD) less than 9.4% and 12.1% for one fiber and different fibers, respectively, and recoveries of 78.9-115.9%. The proposed method can be used for analysis of PAHs in environmental water samples.

Large-scale spinning assembly of neat, morphology-defined, graphene-based hollow fibers.

Large-scale assembly of graphenes in a well-controlled macroscopic fashion is important for practical applications. We have developed a facile and straightforward approach for continuous fabrication of neat, morphology-defined, graphene-based hollow fibers (HFs) via a coaxial two-capillary spinning strategy. With a high throughput, HFs and necklace-like HFs of graphene oxide have been well-controlled produced with the ease of functionalization and conversion to graphene HFs via simply thermal or chemical reduction. This work paves the way toward the mass production of graphene-based HFs with desirable functionalities and morphologies for many of important applications in fluidics, catalysis, purification, separation, and sensing.

Textile electrodes woven by carbon nanotube-graphene hybrid fibers for flexible electrochemical capacitors.

Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers.

Facile fabrication of light, flexible and multifunctional graphene fibers.

Macroscopic graphene fibers with strength comparable to carbon nanotube yarns have been fabricated with a facile dimensionally-confined hydrothermal strategy from low-cost, aqueous graphite oxide suspensions, which is shapable, weavable, and has a density of less than 1/7 conventional carbon fibers. In combination with the easy in situ and post-synthesis functionalization, the highly flexible graphene fibers can be woven into smart textiles.