Graphene Scrolls Research Articles

A Facile In Situ Sulfurization Strategy for Heterostructured SnS2@Graphene Scrolls Anode with Enhanced Initial Coulombic Efficiency for High‐Energy Lithium Storage

AbstractThe initial Coulombic efficiency (ICE) for anode materials is usually one of important parameters for the energy density improvement of batteries. However, due to the lack of effective regulatory methods, the excellent ICE is usually difficult to achieve for SnS2 systems based on alloying/conversion mechanisms in Li‐storage process. Herein, a heterostructure constructed from SnS2 nanoflakes in situ anchored on graphene scroll (SnS2@GS) is engineered and fabricated involving a facile in situ sulfurization strategy. The SnS2@GS anode benefiting from 1D open and organized ion diffusion pathways, along with rapid charge transfer in the heterogeneous interfaces, achieves improved reversibility and kinetics. This material exhibits a remarkable specific capacity coupled with a high ICE (≈88%) while yielding robust rate properties. These exceptional lithium storage properties derive from improved conductivity and reduced energy barriers for Li‐ion migration in the heterostructures, as indicated by the density functional theory calculations. Besides, the full‐cell (LiFePO4//SnS2@GS) and the lithium‐ion capacitor based on SnS2@GS anode are assembled and deliver superior energy densities of 330 and 349 W h kg−1, respectively. This proposed approach is also popularized for the fabrication about other metal sulfide wrapped in graphene scroll to construct the anodes with remarkable properties.

Highly Stretchable Graphene Scrolls Transistors for Self-Powered Tribotronic Non-Mechanosensation Application.

Owing to highly desired requirements in advanced disease diagnosis, therapy, and health monitoring, noncontact mechanosensation active matrix has drawn considerable attention. To satisfy the practical demands of high energy efficiency, in this report, combining the advantage of multiparameter monitoring, high sensitivity, and high resolution of active matrix field-effect transistor (FET) with triboelectric nanogenerators (TENG), we successfully developed the tribotronic mechanosensation active matrix based on tribotronic ion gel graphene scrolls field-effect transistors (GSFET). The tribopotential produced by TENG served as a gate voltage to modulate carrier transport along the semiconductor channel and realized self-powered ability with considerable decreased energy consumption. To achieve high spatial utilization and more pronounced responsivity of the dielectric of this transistor, ion gel was used to act as a triboelectric layer to conduct friction and contact electrification with external materials directly to produce triboelectric charges to power GFET. This tribopotential-driving device has excellent tactile sensing properties with high sensitivity (1.125 mm-1), rapid response time (~16 ms), and a durability operation of thousands of cycles. Furthermore, the device was transparent and flexible with the capability of spatially mapping touch stimuli and monitoring real-time temperature. Due to all these unique characteristics, this novel noncontact mechanosensation GSFET active matrix provided a new method for self-powered E-skin with promising potential for self-powered wearable devices and intelligent robots.

Energy evolution mechanism of nanonetwork from hydrogenated graphene scrolls

Energy evolution mechanism of nanonetwork from hydrogenated graphene scrolls

Inner phase hybridization engineering of core-shell structure confined in graphene scroll for boosting electromagnetic wave absorption

Rational manipulation of low dimensional composite materials with tunable phase hybridization and hierarchical structure is evolving as a promising strategy to boost electromagnetic (EM) wave absorption performance. Herein, a cation-π interaction-driven assembly and carbothermic reduction strategy is proposed to construct the hierarchical 0D core-shell embedded 1D reduced graphene oxide (rGO) scroll aerogels with tuning phase hybridization in the inner core as EM wave absorption materials for the first time. The metal ions can form strong cation-π interaction with CNTs and graphene oxide (GO) to drive the rolling of GO on the surface of CNTs, generating 1D scroll. During the pyrolysis, the metal ions evenly dispersed in the interlayers of graphene scroll can be in-situ reduced to produce the multiple component magnetic nanoparticles which are coated by carbon to form 0D core-shell structure and phase hybridization of the inner core can be easily regulated by the temperature. Due to the optimized interfacial polarization effect and magnetic-dielectric synergy, the aerogel obtained at pyrolysis temperature of 650 °C exhibit ultrahigh EM wave absorption performance with a minimum reflection loss of −88.70 dB with effective absorption bandwidth of 7.30 GHz at 2.99 mm, overpassing most of the known EM wave absorption materials. This work as a comprehensive research provides a deep understanding upon the primary contribution of phase hybridization and hierarchical structure, well inspiring the further development of low dimensional EM wave absorption materials.

Inner Phase Hybridization Engineering of Core-Shell Structure Confined in Graphene Scroll for Boosting Electromagnetic Wave Absorption

Inner Phase Hybridization Engineering of Core-Shell Structure Confined in Graphene Scroll for Boosting Electromagnetic Wave Absorption

Graphene functionalized hybrid nanomaterials for industrial-scale applications: A systematic review

As of remarkable electrical, optical, magnetic, thermal and mechanical properties and large specific surface area, graphene belongs to two-dimensional material of sp2 hybridization carbon atoms, has attracted a lot of interest in the recent decades. For the enormous utilization of graphene in nanoelectronics, the production of high quality graphene in large scale is essential. The properties and applications of this 2-D carbon structure have opened up new possibilities for potential systems and devices. Due to its unique properties in relation to other carbon nanomaterials, research interest in this material grew quickly. Though there are numerous graphene generating techniques, complications in the production of large scale, highly ordered structures of graphene have triggered advanced research in this area leading to the development of a broad spectrum of graphene nanostructures. Utilities of graphene is often behaving as a composite or filler material with metals, metal oxides and polymers. The customization of graphene properties and surface chemistry is focused on controlling its performance in a polymer matrix device. Due to its unusual combination of excellent properties, graphene has evolved as one of the most innovative nanomaterials. ‘Graphene’ is so thick that not even helium, the smallest gas atom, can move through it and it is impermeable to gasses. The typical review overviews the current understanding of the properties of graphene and its derivatives such as: graphene oxide (GO), porous graphene and porous graphene oxide, graphene oxide incorporated liquid crystal (GO-LC), graphene scroll. The review emphasis on simple and effective methodologies for the development of graphene nanocomposite. Various components of smart synthesis techniques are illustrated. Furthermore systematic review explored, interesting applications diversities of graphene and its derivatives, especially in the field of electronics, energy storage were examined along with the potential prospects for their further development, key challenges and significant opportunities in the industrial potential scale.

Lithium‐Ion Batteries: Mn‐Substituted Tunnel‐Type Polyantimonic Acid Confined in a Multidimensional Integrated Architecture Enabling Superfast‐Charging Lithium‐Ion Battery Anodes (Adv. Sci. 3/2021)

In article number 2002866, Hao Wu, Yun Zhang, and co-workers engineer a novel multidimensional integrated architecture, consisting of 0D Mn-substituted tunnel-type polyantimonic acid (PAA) embedded in 1D graphene scrolls that are co-assembled with 2D graphene sheets, to improve the electronic conductivity of PAA and accommodate its volume expansion. As a result, the optimized PAA-based composite enables extraordinary superfast charging capability and robust cycling stability in high-performance rechargeable lithium ion batteries.

Mn‐Substituted Tunnel‐Type Polyantimonic Acid Confined in a Multidimensional Integrated Architecture Enabling Superfast‐Charging Lithium‐Ion Battery Anodes

Given the inherent features of open tunnel‐like pyrochlore crystal frameworks and pentavalent antimony species, polyantimonic acid (PAA) is an appealing conversion/alloying‐type anode material with fast solid‐phase ionic diffusion and multielectron reactions for lithium‐ion batteries. Yet, enhancing the electronic conductivity and structural stability are two key issues in exploiting high‐rate and long‐life PAA‐based electrodes. Herein, these challenges are addressed by engineering a novel multidimensional integrated architecture, which consists of 0D Mn‐substituted PAA nanocrystals embedded in 1D tubular graphene scrolls that are co‐assembled with 2D N‐doped graphene sheets. The integrated advantages of each subunit synergistically establish a robust and conductive 3D electrode framework with omnidirectional electron/ion transport network. Computational simulations combined with experiments reveal that the partial‐substitution of H3O+ by Mn2+ into the tunnel sites of PAA can regulate its electronic structure to narrow the bandgap with increased intrinsic electronic conductivity and reduce the Li+ diffusion barrier. All above merits enable improved reaction kinetics, adaptive volume expansion, and relieved dissolution of active Mn2+/Sb5+ species in the electrode materials, thus exhibiting ultrahigh rate capacity (238 mAh g−1 at 30.0 A g−1), superfast‐charging capability (fully charged with 56% initial capacity for ≈17 s at 80.0 A g−1) and durable cycling performance (over 1000 cycles).

Influence of probe amplitude on the preparation of graphene scroll by probe ultrasonicator technique

The graphene scroll is a new material that influences future applications. Literature reveals that it is much effort is required to prepare the graphene scroll by different techniques. In this paper, facile synthesis of graphene scroll was obtained using probe ultrasonicator with a mixture of ethanol and water. The confirmation of graphene scroll preparation was analyzed by different characterization techniques. Graphene scroll is confirmed by Transmission Electron microscopy with SAED pattern, EDS confirmed the elements. Raman spectrum reveals the formation graphene and graphene scroll. XRD spectrum is shown the interlayer spacing between layers. Absorption spectrum was recorded of graphene using UV–Visible spectrometer. Raman spectrum proves that the prepared material is graphene. The formation of the graphene scroll mechanism was analyzed.

In situ anchoring MnO nanoparticles on self-supported 3D interconnected graphene scroll framework: A fast kinetics boosted ultrahigh-rate anode for Li-ion capacitor

Lithium ion capacitors (LICs) are deemed to be an ideal complement between lithium-ion batteries and supercapacitors. However, the sluggish kinetics that leads to a poor rate capability of Faradaic insertion anodes remains a handicap. Herein, a self-supported architecture is designed by combining an interconnected graphene scroll (GS) framework with in situ formed well-distributed MnO nanoparticles (NPs) for an advanced LIC anode. In this architecture, the inner-connected tubular GS framework plays a multifunctional role: serving as an electron transport bridge like “highways”, providing a favorable ion transport pathway as well as accommodating the volume expansion and maintaining the structural stability of MnO. Benefiting from the stable structure, highly localized charge-transfer and low energy diffusion barrier, the as-built anode exhibits an ultrahigh-rate behavior (203 mAh g−1 at 20 A g−1) and robust cycling stability (759 mAh g−1 after 1000 cycles at 2 A g−1). When evaluated as a self-supported anode for LIC, the LIC delivers a high energy density of 179.3 Wh kg−1, a high power density of 11.7 kW kg−1, and a capacity retention of 80.8% after 5000 cycles. Moreover, the corresponding soft-packaged LIC keeps stable electrochemical performances at various bending states. All these features manifest the potential of the architecture for application in advanced energy storage devices.

Nitrogen-doped and reduced graphene oxide scrolls derived from chemical exfoliation of vapor-grown carbon fibers for electrochemical supercapacitors

Vapor-grown carbon fibers with partially disordered graphitic structure allow for the formation of graphene oxide scrolls (GOSs) through a solution-based chemical exfoliation along their longitudinal directions. Heat treatment of GOS at 300 °C in an air atmosphere forms the partially reduced GOS (denoted as HT-RGOS) with curved and hydrophobic graphene oxide sheets. Hydrothermal treatment of GOS in urea solution results in the formation of N-doped and reduced GOS (denoted as N-RGOS) with more curved and hydrophilic surface than the HT-RGOS. The charge-storage behavior of HT-RGOS and N-RGOS electrodes in 1M KOH electrolyte is mostly dominated by the pseudocapacitive faradaic processes, while the GOS electrode is characterized by both the pseudocapacitive faradaic and non-capacitive processes. The specific capacitance of N-RGOS electrode reaches 228 F g−1 which is greater than that of GOS (77 F g−1) and HT-GOS (190 F g−1) electrodes at a current density of 1 A g−1. The improved supercapacitive behavior of N-RGOS results from the enhanced hydrophilicity and electrical conductivity by the introduction of nitrogenous groups to the N-RGOS that enable the easy transport of electrolyte and electron through the graphene scrolls.

Electrochemically activated MnO cathodes for high performance aqueous zinc-ion battery

Aqueous Zn-ion batteries (ZIBs) attract ever-growing attention due to low cost, high safety, and environmental friendliness. Among the limited cathode candidates, manganese-based oxides stand out owing to large ion channels and multiple valence of Mn. Notably, MnO, thought to be inactive before, actually exhibits high energy densities in AZIBs, thus arousing wide interests. Herein, the electrochemical behavior of MnO electrode is extensively investigated in ZnSO4 electrolytes with different concentration of MnSO4. It is confirmed that the inactive MnO is electrochemically activated during the initial charge process. Greatly, the initial capacity and the following cycling stability of MnO electrode strongly depends on the concentration of MnSO4, indicating that the activation of MnO could be attributed to Mn dissolution, leading to the higher valence of Mn as evidenced by ex-situ XPS analysis. Greatly, a H+/Zn2+ co-insertion mechanism is suggested for the as-activated Mn1-xO electrode according to the ex-situ XRD results. In addition, by constructing a core-sheath MnO@N-doped graphene scrolls (MnO@NGS) configuration through a modified hydrothermal process, the reversible capacity of MnO has been successfully improved to 288 mAh g−1 (0.1 A g−1), leading to high energy density of 367 mWh g−1. More importantly, benefiting from the graphene wrapping and sufficient internal voids, 98% of the initial capacity can be retained after 300 cycles (0.5 A g−1), much better than the unmodified MnO and MnO2 electrodes. This work is expected to deepen the understanding of the charge-storage mechanism of MnO and help to design durable manganese-based cathodes for ZIBs.

Building defect-rich oxide nanowires@graphene coaxial scrolls to boost high-rate capability, cycling durability and energy density for flexible Zn-ion batteries

Transition metal oxides with earth abundance and high theoretical capacity have received ever-growing interests as promising cathode materials for aqueous zinc-ion batteries (ZIBs). However, their semiconducting nature and poor conductivity lead to the kinetically sluggish rate and poor electrochemical reversibility. Herein, a novel defect-rich oxide nanowire filled graphene scrolls (denoted as DNGS) is introduced as a high-performance cathode for ZIBs. The 1D ultrathin oxide nanowires with defective nature are enwrapped in the center of the graphene scrolls, forming the core-shell coaxial scrolls. Benefitting from the highly conductive graphene network and 1D structured oxide with defect-rich structure, the DNGS hybrid scrolls achieve fast electron/ion transport, high electrochemical reversibility and superior energy storage capability. For the first time, the defect-rich vanadate oxide (V6O13-δ) is employed to construct the DNGS structure. The evolution of the DNGS structure is probed and the sequential mechanism based on the “oriented growth, self-assembly and self-rolling” process is disclosed. Both experimental and theoretical analyses demonstrate the significant increase in the electronic conductivity, ionic diffusion capability and electrochemical properties of the DNGS hybrid scrolls in comparison with the reference ones. The DNGS sample achieves ultrafast discharge capability and excellent deep cycling stability. Moreover, the flexible ZIBs based on the DNGS cathode display excellent high-rate long-term cycling stability (97% after 1000 cycles at alternative 13 and 4 A g−1) and admirable energy density (max. 231 mWh cm−3). Even under severe external deformation, the superior properties are well-retained which prove their high reliability. Therefore, this work not only provides a highly efficient structure to improve properties of oxides, but also propel the development of ZIBs for broadened applications.

Vortex fluidic mediated transformation of graphite into highly conducting graphene scrolls

Two-dimensional graphene has remarkable properties that are revolutionary in many applications. Scrolling monolayer graphene with precise tunability would create further potential for niche applications but this has proved challenging. We have now established the ability to fabricate monolayer graphene scrolls in high yield directly from graphite flakes under non-equilibrium conditions at room temperature in dynamic thin films of liquid. Using conductive atomic force microscopy we demonstrate that the graphene scrolls form highly conducting electrical contacts to highly oriented pyrolytic graphite (HOPG). These highly conducting graphite–graphene contacts are attractive for the fabrication of interconnects in microcircuits and align with the increasing interest in building all sp2-carbon circuits. Above a temperature of 450 °C the scrolls unravel into buckled graphene sheets, and this process is understood on a theoretical basis. These findings augur well for new applications, in particular for incorporating the scrolls into miniaturized electronic devices.

Model of Metamaterial Based on Graphene Scrolls and Carbon Nanotubes with Negative Refractive Index

The structure of a new metamaterial with negative permittivity and permeability that is made of periodically positioned graphene/boron nitride nanoscrolls and carbon nanotubes is proposed. The parameters of the metamaterial structure with a negative refractive index for the frequency of an electromagnetic wave within the visible range (namely, from near infrared to yellow) are calculated.

Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures.

Graphynes and graphdiynes are generic names for families of two-dimensional carbon allotropes, where acetylenic groups connect benzenoid-like hexagonal rings, with the coexistence of sp and sp2 hybridized carbon atoms. The main differences between graphynes and graphdiynes are the number of acetylenic groups (one and two for graphynes and graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like structures. In this work we studied through molecular dynamics simulations, using reactive potentials, the structural and thermal (up to 1000 K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne scrolls. Our results demonstrate that stable nanoscrolls can be created for all the structures studied here, although they are less stable than corresponding graphene scrolls. This can be elucidated as a result of the higher graphyne/graphdiyne structural porosity in relation to graphene, and as a consequence, the π-π stacking interactions decrease.

Graphene-scroll-sheathed α-MnS coaxial nanocables embedded in N, S Co-doped graphene foam as 3D hierarchically ordered electrodes for enhanced lithium storage

One-dimensional (1D) nanomaterials have been recognized as ideal nanoscale building blocks to build multi-dimensional and multi-functional electrode configurations for electrochemical energy storage, owing to their unique structural advantages. Herein, a hierarchical transition-metal-sulfide-based electrode configuration is designed by constructing N, S co-doped 3D graphene foam with embedded 1D ultra-long α-MnS nanowires sheathed within graphene scrolls. This structural engineering strategy relies on forming coaxial nanocables comprising core-sheath α-MnS@graphene scrolls via a hydrothermally-assisted self-scrolling and self-assembly process, coupled with a sulfidation treatment. The coaxial nanocable as the structural unit is able to accommodate the volume expansion of the enclosed α-MnS by external elastic graphene scrolls together with internal void spaces, and thus ensures the interfacial stabilization of the solid electrolyte interphase layer. Meanwhile, N, S co-doped graphene foam with a cross-linked 3D structure offers continuous conductive paths for fast electron transfer, and also helps to maintain the structural and electrical integrity of the electrode. Because of the unique structural merits, the hierarchically ordered electrode delivers remarkably enhanced rate (406 mAh g−1 at 2000 mA g−1) and cycling capability (519 mAh g−1 after 400 cycles at 1000 mA g−1). Such a hierarchical structure design may present rational synthetic strategies to develop durable transition-metal-sulfide-based electrodes.

Mechanics of the scrolling and folding of graphene

The competition between the out-of-plane rigidity and the van der Waals interaction leads to the scrolled and folded structural configurations of graphene. These configuration changes, as compared with the initially planar geometry, significantly affect the electronic, optical and mechanical properties of graphene, promising exciting applications in graphene-nanoelectronics. We propose a finite-deformation theoretical model, in which no presumed assumptions on the geometries of deformed configurations are required. Both the predicted deformed profiles and the critical conditions show great agreements with molecular dynamics simulations results when compared with existing studies with simple geometrical assumptions. Moreover, MD simulations are performed to explore the morphology transitions between different configurations. It is observed that the folded configuration is energetically favorable for a short graphene sheet, while a long graphene sheet tends to scroll. Of particular interest, we observe the morphology transition from a Fermat scroll to the Archimedean scroll for the bi-scrolled graphene. These findings are useful for understanding the stability of graphene and may provide guidance to the design of programmable graphene-nanoelectronics.

Nanoparticle activated and directed assembly of graphene into a nanoscroll

Graphene nanoscrolls (GNS) have emerged as an important class of materials with applications in the field of lubrication, energy storage devices, and catalysis. However, the formation of GNS even with existing advanced experimental techniques could be very challenging. Here, we investigate the ability of diamond, nickel (Ni), platinum (Pt), and gold (Au) nanoparticles (NPs) in activating, guiding, and stabilizing the GNS by performing reactive molecular dynamics (RMD) simulations. NPs of certain diameters, when placed on a free-standing graphene sheet, can activate either wrapping or scrolling of the graphene. This activation is due to non-bonded interactions between graphene and NPs. However, for a complete wrap and scroll formation and its stabilization both graphene-graphene and NPNP interactions were also critical. Surface atoms of Ni and Pt NPs undergo reconstruction during the wrapping or scrolling of graphene, suggesting that the NP-graphene interactions are more favorable as compared to NPNP and graphene-graphene interactions. We have identified new energy criteria which must be satisfied to facilitate a complete GNS formation for the graphene-NP systems investigated in the present study. Overall, our study can provide a new method to design metal-graphene hybrid materials that can be used for a variety of applications.

Graphene Scroll-Coated α-MnO2 Nanowires as High-Performance Cathode Materials for Aqueous Zn-Ion Battery.

The development of manganese dioxide as the cathode for aqueous Zn-ion battery (ZIB) is limited by the rapid capacity fading and material dissolution. Here, a highly reversible aqueous ZIB using graphene scroll-coated α-MnO2 as the cathode is proposed. The graphene scroll is uniformly coated on the MnO2 nanowire with an average width of 5 nm, which increases the electrical conductivity of the MnO2 nanowire and relieves the dissolution of the cathode material during cycling. An energy density of 406.6 Wh kg-1 (382.2 mA h g-1 ) at 0.3 A g-1 can be reached, which is the highest specific energy value among all the cathode materials for aqueous Zn-ion battery so far, and good long-term cycling stability with 94% capacity retention after 3000 cycles at 3 A g-1 are achieved. Meanwhile, a two-step intercalation mechanism that Zn ions first insert into the layers and then the tunnels of MnO2 framework is proved by in situ X-ray diffraction, galvanostatic intermittent titration technique, and X-ray photoelectron spectroscopy characterizations. The graphene scroll-coated metallic oxide strategy can also bring intensive interests for other energy storage systems.