Chuangang Hu

All‐Graphene Core‐Sheath Microfibers for All‐Solid‐State, Stretchable Fibriform Supercapacitors and Wearable Electronic Textiles

Flexible graphene fi ber (GF) stands for a new type of fi ber of practical importance, which integrates such unique properties as high strength, electrical and thermal conductivities of individual graphene sheets into the useful, macroscopic ensembles. GFs possess the common characteristics of fi bers like the mechanical fl exibility for textiles, while maintaining the uniqueness such as low cost, light weight, and ease of functionalization in comparison with conventional carbon fi bers. [ 1–3 ] Due to the extraordinary challenge to assemble two-dimensional (2D) microcosmic graphene sheets with irregular size and shape into macroscopic fi brillar confi guration, however, the success in fabrication of neat graphene fi bers only comes true recently. [ 1–4 ]

A Versatile, Ultralight, Nitrogen‐Doped Graphene Framework

Graphene lite: a density of (2.1 ± 0.3) mg cm(-3), the lowest to date for a graphene framework architecture, is achieved by preparing an ultralight, N-doped, 3D graphene framework (see photo of a block of the material balancing on a dandelion). Its adsorption capacity for oils and organic solvents is much higher than that of the best carbonaceous sorbents, and it is a promising electrode material for supercapacitors (484 F g(-1)) and as a metal-free catalyst for the oxygen reduction reaction.

Highly compression-tolerant supercapacitor based on polypyrrole-mediated graphene foam electrodes.

Deformation-tolerant devices are vital for the development of high-tech electronics of unconventional forms. In this study, a highly compressible supercapacitor has been fabricated by using newly developed polypyrrole-mediated graphene foam as electrode. The assembled supercapacitor performs based on the unique and robust foam electrodes achieves superb compression tolerance without significant variation of capacitances under long-term compressive loading and unloading processes.

Newly-Designed Complex Ternary Pt/PdCu Nanoboxes Anchored on Three-Dimensional Graphene Framework for Highly Efficient Ethanol Oxidation

Newly-designed ternary Pt/PdCu nanoboxes on three-dimensional graphene framework (Pt/PdCu/3DGF) have been fabricated via a dual solvothermal strategy. This structurally well-defined Pt/PdCu/3DGF system possesses an approximately 4-fold improvement in catalytic activity for ethanol oxidation in alkaline media over the commercial 20% Pt/C catalyst as normalized by the total mass of active metals, showing the great potential for direct fuel cell applications.

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.

Graphene Fibers with Predetermined Deformation as Moisture‐Triggered Actuators and Robots

Enough to make your hair curl! Moisture-responsive graphene (G) fibers can be prepared by the positioned laser reduction of graphene oxide (GO) counterparts. When exposed to moisture, the asymmetric G/GO fibers display complex, well-controlled motion/deformation in a predetermined manner. These fibers can function not only as a single-fiber walking robot under humidity alternation but also as a new platform for woven devices and smart textiles.

Tailored graphene systems for unconventional applications in energy conversion and storage devices

Graphene-based materials have shown great potential in various fields across physics, chemistry, biology, and electronics, due to their unique electronic properties, facile synthesis, and ease of functionalization. In this review, we summarize the significant advances in tailored graphene systems for the recently developed unconventional energy conversion and storage devices reported by our group and others, namely focused on their tunable and controllable preparation and remarkable applications in new types of supercapacitors, lithium ion batteries, photovoltaic cells, and other emerging generators. This featured article also highlights the working principles and outlines the problems hindering the practical applications of graphene-based materials in these energy-related devices. Future research trends towards new methodologies in the design and synthesis of graphene-based systems with unique properties for emerging energy storage and energy conversion devices are also proposed.

Functional graphene nanomesh foam

Rationally designed graphene nanomesh assembled foam (GMF) with hierarchical pore arrangement has been successfully fabricated for the first time by a site-localized nanoparticle-induced etching strategy on the basis of hydrothermally self-assembled graphene architecture. The newly developed GMF provides a new material platform for developing high-performance functional devices. Specially, the N- and S-codoped GMF electrode exhibits excellent electrocatalytic activities for oxygen reduction reaction (ORR), better than most of the graphene-based ORR catalysts reported previously.

Spontaneous Reduction and Assembly of Graphene oxide into Three-Dimensional Graphene Network on Arbitrary Conductive Substrates

Chemical reduction of graphene oxide (GO) is the main route to produce the mass graphene-based materials with tailored surface chemistry and functions. However, the toxic reducing circumstances, multiple steps, and even incomplete removal of the oxygen-containing groups were involved, and the produced graphenes existed usually as the assembly-absent precipitates. Herein, a substrate-assisted reduction and assembly of GO (SARA-GO) method was developed for spontaneous formation of 3D graphene network on arbitrary conductive substrates including active and inert metals, semiconducting Si, nonmetallic carbon, and even indium-tin oxide glass without any additional reducing agents. The SARA-GO process offers a facile, efficient approach for constructing unique graphene assemblies such as microtubes, multi-channel networks, micropatterns, and allows the fabrication of high-performance binder-free rechargeable lithium-ion batteries. The versatile SARD-GO method significantly improves the processablity of graphenes, which could thus benefit many important applications in sensors and energy-related devices.

Large scale production of biomass-derived N-doped porous carbon spheres for oxygen reduction and supercapacitors

The urgent need for sustainable energy development depends on the progress of green technologies, which have steered hot research areas into environmentally benign approaches via inexpensive precursors and abundant resources obtained directly from nature for energy devices such as fuel cells and supercapacitors. By using fermented rice as starting materials, we herein demonstrate a facile, green and scalable approach to synthesize porous N-doped carbon spheres characterised by high specific surface areas (2105.9 m2 g−1) and high porosity (1.14 cm3 g−1), which exhibit not only excellent electrocatalytic activity toward the four-electron oxygen reduction reaction with long-term stability for fuel cells, but also have excellent resistance to crossover effects and CO poisoning superior to that of the commercial Pt/C catalyst. Furthermore, the naturally derived porous N-doped carbon spheres, used as the active electrode materials, present superior performance for capacitors with a capacitance of 219 F g−1 at a high discharge current density of 15 A g−1 and good cycling stability for over 4400 cycles. This work shows a good example for taking advantage of the abundant resources provided by nature, and opening the door for the creation of functional materials with promising applications in high-performance renewable devices related to energy conversion and storage.