Haiyan Sun

Multifunctional, Ultra‐Flyweight, Synergistically Assembled Carbon Aerogels

All carbon aerogels (up to 1000 cm(3)) with ultralow density (down to 0.16 mg cm(-3)) and temperature-invariant (-190-900 °C) super-elasticity are fabricated by facile assembling of commercial carbon nanotubes (CNTs) and chemically-converted giant graphene sheets, on the basis of the synergistic effect between elastic CNTs ribs and giant graphene cell walls.

Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm−2 and energy densities of 5.91 and 3.84 μWh cm−2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics.

Ultrastrong Fibers Assembled from Giant Graphene Oxide Sheets

Continuous, ultrastrong graphene fibers are achieved by wet-spinning of giant graphene oxide liquid crystals, followed by wet-drawing and ion-cross-linking. The giant size and regular alignment of graphene sheets render the fibers with high mechanical strength and good conductivity. Such graphene fibers promise wide applications in functional textiles, flexible and wearable sensors, and supercapacitor devices.

Highly Electrically Conductive Ag‐Doped Graphene Fibers as Stretchable Conductors

Ag-doped graphene fibers show remarkable electrical conductivity, high current capacity, good mechanical strength and fine flexibility. The integration of these merits promises Ag-doped graphene fibers expanding applications as stretchable conductors, wearable electronics, and actual microcables.

An iron-based green approach to 1-h production of single-layer graphene oxide

As a reliable and scalable precursor of graphene, graphene oxide (GO) is of great importance. However, the environmentally hazardous heavy metals and poisonous gases, explosion risk and long reaction times involved in the current synthesis methods of GO increase the production costs and hinder its real applications. Here we report an iron-based green strategy for the production of single-layer GO in 1 h. Using the strong oxidant K2FeO4, our approach not only avoids the introduction of polluting heavy metals and toxic gases in preparation and products but also enables the recycling of sulphuric acid, eliminating pollution. Our dried GO powder is highly soluble in water, in which it forms liquid crystals capable of being processed into macroscopic graphene fibres, films and aerogels. This green, safe, highly efficient and ultralow-cost approach paves the way to large-scale commercial applications of graphene.

A Highly Efficient Metal-Free Oxygen Reduction Electrocatalyst Assembled from Carbon Nanotubes and Graphene.

A novel carbon-nanotube-graphene hybrid nanostructure is developed using an aerosol-assisted assembly approach. After doping with nitrogen and phosphorus, the prepared hybrid nanomaterials exhibit excellent electrocatalytic performance for oxygen reduction in both alkaline and acidic media. This research presents a continuous and low-cost route to prepare high-performance metal-free electrocatalysts while replacing Pt-based materials.

Ultrastiff and Strong Graphene Fibers via Full‐Scale Synergetic Defect Engineering

Kilometer-scale continuous graphene fibers (GFs) with outstanding mechanical properties and excellent electrical conductivity are produced by high-throughput wet-spinning of graphene oxide liquid crystals followed by graphitization through a full-scale synergetic defect-engineering strategy. GFs with superior performances promise wide applications in functional textiles, lightweight motors, microelectronic devices, and so on.

Solution processible hyperbranched inverse-vulcanized polymers as new cathode materials in Li–S batteries

Soluble inverse-vulcanized hyperbranched polymers (SIVHPs) were synthesized via thiol–ene addition of polymeric sulfur (S8) radicals to 1,3-diisopropenylbenzene (DIB). Benefiting from their branched molecular architecture, SIVHPs presented excellent solubility in polar organic solvents with an ultrahigh concentration of 400 mg mL−1. After end-capping by sequential click chemistry of thiol–ene and Menschutkin quaternization reactions, we obtained water soluble SIVHPs for the first time. The sulfur-rich SIVHPs were employed as solution processible cathode-active materials for Li–S batteries, by facile fluid infiltration into conductive frameworks of graphene-based ultralight aerogels (GUAs). The SIVHPs-based cells showed high initial specific capacities of 1247.6 mA h g−1 with 400 charge–discharge cycles. The cells also demonstrated an excellent rate capability and a considerable depression of shuttle effect with stable coulombic efficiency of around 100%. The electrochemical performance of SIVHP in Li–S batteries overwhelmed the case of neat sulfur, due to the chemical fixation of sulfur. The combination of high solubility, structure flexibility, and superior electrochemical performance opens a door for the promising application of SIVHPs.

Perspective: Graphene aerogel goes to superelasticity and ultraflyweight

Three-dimensional graphene-based aerogels have been promoted to present fascinating superelasticity and ultralightness by the intelligent design on microstructures. In this perspective, we conclude the recent design strategies to realize these dual elasticity and lightness, and look forward to the promising applications of graphene-based aerogels with multifunctional merits.