Conductive Graphene Network Research Articles

Multifunctional laser-ablated lubricant-infused slippery film with self-sensing and anti-icing/deicing properties

In this paper, we have developed a multifunctional laser-ablated lubricant-infused slippery film (MLLSF) by combining laser-induced graphene and lubricant-infused processes. Due to its lubricant-infused slippery surface characteristics, the MLLSF can decrease the ice adhesion strength to 7 kPa and prolong the ice time to 5 min at -20 °C. At the same time, benefitting from the outstanding photothermal effect of the laser-induced graphene conductive network, the surface temperature can rapidly rise from -20 °C to 45.6 °C in 60 s under 808-NIL illumination, thereby effectively melting the ice. More importantly, owing to the temperature sensing ability of the LIG conductive network, the prepared MLLSF can monitor the whole process of droplet icing and deicing process in real time. Therefore, this MLLSF with self-sensing, anti-icing and deicing properties has important practical values in monitoring and removing ice.

Weakly negative permittivity from three-dimensional printed polydimethylsiloxane/graphene films in the radio frequency band

Epsilon-negative materials (ENMs) has become a research hotspot due to their unique physical properties and practical applications in fields such as directional radiation and tunneling effects. In this work, weakly negative permittivity (from -50 at 10 kHz to -25 at 1 MHz) was realized from three-dimensional printed polydimethylsiloxane/graphene films. The dielectric properties including complex permittivity (ε', ε″), complex impedance (Z', Z″), alternating current conductivity (σac), and dielectric loss tangent (tanδ) were investigated. When graphene content reached 15 wt%, the interconnected graphene network was formed, resulting in negative permittivity. Theory calculations were further used to explore the mechanism. The electrons around carbon atoms showed significant delocalization. With the effect of the external electromagnetic field, the electrons on the surface of graphene could easily oscillate collectively, leading to negative permittivity. Differential charge density exhibited that interfacial electric fields were formed between polydimethylsiloxane and graphene, enhancing positive permittivity. Therefore, when the graphene content reached 15 wt%, the film exhibited weakly negative permittivity, which was the result of the mutual balance between the graphene conductive network and the interface electric fields.

Synergistic enhancement of ion/electron transport by ultrafine nanoparticles and graphene in Li2FeTiO4/C/G nanofibers for symmetric Li-ion batteries

Low-cost Fe-based disordered rock salt (DRX) Li2FeTiO4 is capable of providing high capacity (295 mA h g−1) by redox activity of cations (Fe2+/Fe4+ and Ti3+/Ti4+) and anionic oxygen. However, DRX structures lack transport channels for ions and electrons, resulting in sluggish kinetics, poor electrochemical activity, and cyclability. Herein, graphene conductive carbon network permeated Li2FeTiO4 (LFT/C/G) nanofibers are successfully prepared by a facile sol-gel assisted electrospinning method. Ultrafine Li2FeTiO4 nanoparticles (2 nm) and one-dimensional (1D) structure provide abundant active sites and unobstructed diffusion channels, accelerating ion diffusion. In addition, introducing graphene reduces the band gap and Li+ diffusion barrier and improves the dynamic properties of Li2FeTiO4, thus achieving a relatively mild interfacial reaction and reversible redox reaction. As expected, the LFT/C/1.0G cathode delivers a remarkable discharge capacity (238.5 mA h g−1), high energy density (508.8 Wh kg−1), and excellent rate capability (51.2 mA h g−1 at 1.0 A g−1). Besides, the LFT/C/1.0G anode also displays a high capacity (514.5 mA h g−1 at 500 mA g−1) and a remarkable rate capability (243.9 mA h g−1 at 8 A g−1). Moreover, the full batteries based on the LFT/C/1.0G symmetric electrode demonstrate a reversible capacity of 117.0 mA h g−1 after 100 cycles at 50 mA g−1. This study presents useful insights into developing cost-effective DRX cathodes with durable and fast lithium storage.

Ultrafast reaction kinetic of polyaniline in flexible hydrogel electrodes facilitated by graphene ribbons

Abstract By loading energy storage active materials on hydrogel which is inherently flexible, the flexibility of electrode materials can be simply realized, thereby achieving the flexibility of energy storage devices. However, the polymer network that constructs the three-dimensional skeleton of the hydrogel is not conductive, which inhibits the redox ability of the active material. If a high speed conductive structure can be added to the colloidal phase, the performance of the flexible electrode material can be greatly improved. Here, we introduce redox graphene ribbons into the polyvinyl alcohol hydrogel loaded with polyaniline. The in situ three-dimensional conductive graphene network greatly enhanced the conductivity of the hydrogel electrode, thus increasing the specific capacitance to as high as 1117 F g−1 at 2 mg cm−2 mass loading, with a retention ratio of 66.96% from 0.5 A g−1 to 20 A g−1. These highlighted properties enable the PRP hydrogel as an electrode for flexible supercapacitors, which provides a promising possibility for the practical application of wearable electronics.

Biocompatible and Biodegradable 3D Graphene/Collagen Fiber Hybrids for High-Performance Conductive Networks and Sensors.

Polymer-based flexible conductive materials are crucial for wearable electronics, electronic skin, and other smart materials. However, their development and commercial applications have been hampered by the lack of strain tolerance in the conductive network, poor bonding with polymers, discomfort during wear, and a lack of biocompatibility. This study utilized oil-tanned leather with a natural network structure, high toughness, and high tensile deformation recovery as a structural template. A graphene (Gr) conductive network was then constructed on the collagen network of the leather, with coordination cross-linking between Gr and collagen fibers through aluminum ions (Al3+). A new flexible conductive material (Al-GL) was then constructed. Molecular dynamics simulations and experimental validation revealed the existence of physical adsorption, hydrogen bonding adsorption, and ligand bonding between Al3+, Gr, and collagen fibers. Although we established that the binding sites between Al3+ and collagen fibers were primarily on carboxyl groups (-COOH), the mechanism of chemical bonding between Gr and collagen fibers remains unclear. The Al-GL composite exhibited a high shrinkage temperature (67.4 °C) and low electrical resistance (16.1 kΩ·sq-1), as well as good softness (9.33 mN), biocompatibility, biodegradability (<60 h), and air and moisture permeability. Furthermore, the incorporation of Al3+ resulted in a heightened Gr binding strength on Al-GL, and the resistance remained comparable following 1 h of water washing. The Al-GL sensor prepared by WPU encapsulation not only demonstrated highly sensitive responses to diverse motion signals of the human body but also retained a certain degree of response to external mechanical effects underwater. Additionally, the Al-GL-based triboelectric nanogenerator (Al-GL TENG) exhibited distinct response signals to different materials. The Al-GL prepared by the one-pot method proposed in this study offers a novel approach to combining functional nanofillers and substrate materials, providing a theoretical foundation for collagen fiber-based flexible conductive materials.

High conductive poly(1,8-diaminonaphthalene)/graphene nanocomposite as a cathode for zinc ion batteries

Recently, aqueous zinc ion batteries (AZIBs) are experiencing rapid development benefiting to their high safety and increasing electrochemical performance. Among all kinds of AZIB electrode materials, organic materials have attracted attentions due to their unique advantages such as structural flexibility, small volume expansion, abundant Zn2+ storage sites and environmental friendliness. However, issues involving electrode dissolution, sluggish electrochemical kinetics etc. still hampered the prior choice of organic electrodes. Herein, we designed a poly(1,8-diamino-naphthalene)/ graphene composite aiming to improve the availability of organic electrodes in AZIBs. By means of constructing high conducting graphene network and the synergetic effect between the two components, the electronic transfer kinetics and overall electrochemical performance of PDAN organic electrode have been fully improved. The organic-inorganic composite exhibited an initial specific capacity of 240 mA·h·g−1 and stable galvanostatic cycling after 1000 cycles, exceeding the original polymer.

Pomegranate‐Inspired Cathodes Mitigate the Mismatch Between Carrier Transport and High Loading for Aqueous Zinc‐Ion Batteries

AbstractThe development of high‐energy‐density aqueous zinc‐ion batteries requires the preparation of cathodes with a thick layer of active material. However, the insulating nature and dissolution of vanadium‐based oxides lead to low areal capacity (0.1,1 mA h cm−2) during the charge/discharge cycle. Herein, V2O5 nanospheres are generated by anchoring onto the laser‐induced graphene (LIG) conductive network through defect‐induced adsorption, resulting in the formation of pomegranate‐like V2O5@LIG composites. The unique and abundant defect structure in the honeycomb LIG can trigger the formation of uniform V2O5 nanospheres with high specific surface area and interact electronically with V2O5 to enhance the electrical conductivity of the cathode materials up to four orders of magnitude. In contrast to conventional carbon materials that can cause steric hindrance for ion transport, the micropores within LIG shorten the ion transport path through the cathode. Concurrently, the pomegranate‐like encapsulated structure effectively prevents cathode material corrosion. Under a high‐loading mass of 17.1 mg cm−2, the full cell is stably cycled for 200 cycles, possessing a 92.5% capacity retention, and achieving a high areal capacity of 6.05 mA h cm−2.

Graphene–Encapsulated Si@C with Dual Carbon Layer Structure as High‐Performance Anode Materials for Lithium–Ion Batteries

AbstractSilicon–based materials are among the highly promising anode candidates for Li–ion batteries owing to their excellent theoretical energy density. However, the huge volume variation makes the application of silicon anode in lithium–ion batteries be full of challenge. Herein, high–performance Si@C@rGO composites anode for lithium–ion batteries are successfully prepared by graphene oxide (GO) uniformly encapsulating resorcinol–formaldehyde resin (RF) coated silicon nanoparticles. The RF‐derived carbon layer can prevent the silicon from direct contact with the electrolyte. Furthermore, the continuous conductive graphene network not only improves the overall electrical conductivity of the composite material, but also can be reversibly deformed with the volume change of silicon during the charging and discharging process, thus greatly improving the structural stability of the anode. The optimal Si@C@rGO‐2 composite provides a high specific capacity of 743.9 mAh g−−1 after 300 cycles at a current density of 1 A g−1. Meanwhile, the material also exhibits good rate performance, showing a good reversible capacity of 719.5 mAh g−1 even at a high current density of 2 A g−1. In addition, this simple and low‐cost strategy of Si@C@rGO anode can provide a design reference for the further development of anode materials in lithium–ion batteries.

Fast and stable lithium extraction enabled by less-defective graphene supported LiMn2O4 conductive networks in hybrid capacitive deionization

Hybrid capacitive deionization (HCDI) technology for lithium (Li+) extraction from brine has received growing concern owing to its easy operation, low energy consumption, and environmental friendliness. LiMn2O4 (LMO) as an affordable Li+ extraction material offers a high theoretical capacity, while the slow ion insertion kinetics and unavoidable Mn dissolution restrict its wide usage. Herein, an LMO-based electrode supported by less-defective (inherent lattice defects and oxygen-containing defects), interconnected graphene conductive networks is proposed for fast and stable Li+ extraction from brine using HCDI. The rGO/LMO electrode displays an excellent conductivity of 0.42 S·cm−1 and a high specific capacitance of 418.26 F·g−1. In the HCDI system, the rGO/LMO electrode delivers a Li+ adsorption capacity up to 4.34 mmol·g−1 with a rapid adsorption rate of 0.33 mmol·g−1·min−1 (0.05 mol·L–1 LiCl, 1.0 V), demonstrating both of the outstanding adsorption capacity and rate abilities as defined by Ragone plots. In a solution with a high Mg2+/Li+ molar ratio of 20, the separation factor can reach 71.32. By employing rGO/LMO electrode to simulated Atacama brine, the separation factor of Li+ from Na+, K+, Ca2+, and Mg2+ are calculated to be 473.89, 74.86, 63.07, and 38.55. Particularly, the rGO/LMO electrode shows remarkable cycling stability with a capacity retention rate of 90.73 % (50 cycles). This developed less-defective graphene-wrapped LMO electrode holds significant importance in enhancing selective Li+ extraction performance with fast rate and stability.

Embedded printing of graphene sponge sensors for sleep monitoring

This study presents an approach for developing sleep monitoring sensors with excellent satisfactory softness, sensitivity and stability by embedding three-dimensional graphene conductive network patterns onto sponges.

Photoconversion and photoelectron storage coatings based on PANI, BiVO4 and graphene

Based on one of the most abundant resources on earth—sunlight, photocathodic protection (PCP) coating is a photoelectron-saving and intelligent anti-corrosion measure. Herein, we created a photoconversion and photoelectron storage coating composed of epoxy resin matrix, graphene, and sunlight-responsive polyaniline@bismuth vanadate nanocomposites (PANI@BiVO4). The PANI@BiVO4 nanocomposites were evenly distributed into the 3D network formed by graphene flakes. Such a unique design allows for storing the generated electrons, from the photoelectric conversion of BiVO4 upon light exposure, in the layer of PANI via electrochemical reactions. The stored electrons can be released along the 3D conductive graphene network to the metal interface even in dark conditions for more than 12 h.

Hybrid crosslinking for in-situ encapsulation of three-dimensional porous SiOx@rGO as high-performance anodes in lithium-ion batteries

Silicon suboxide (SiOx) anodes have garnered significant attention from both academia and industry due to their superior theoretical capacity compared to graphite, as well as their improved capacity retention in comparison to pure silicon. Nevertheless, SiOx electrodes still confront the challenge of substantial volume expansion (>160 %) during the alloying process, resulting in electrode structural damage or even fragmentation and severely impacting cycling performance. Here, a three-dimensional (3D) conductive network was constructed by ethylenediamine (EDA) cross-linking reduced graphene oxide (rGO), which was encapsulated on the surface of SiOx spheres generated in situ via a magnesium thermal reduction reaction. Accordingly, the SiOx@rGO-EDA anode was prepared successfully with high reversible capacity (892 mAh g−1 after 100 cycles at 1 A g−1) and fascinating rate performance (447 mAh g−1 at 4 A g−1). In full cell, the SiOx@rGO-EDA anode also exhibits outstanding cycling stability (154 mAh g−1 after 100 cycles at 0.1C) and rate capability. The scanning electron microscopy (SEM) images captured from a top-view perspective indicate that the surface of SiOx@rGO-EDA electrode is smooth and dense without any noticeable cracks, and it maintains its structural integrity throughout the cycling process. The cross-sectional thickness of the electrode remains essentially the same. These results illustrate the superior structural stability of the EDA cross-linked graphene conductive network cladding structure, enabling it to adapt to dynamic changes and ensure efficient transport of lithium ions and electrons. The facile and versatile synthesis method of SiOx@rGO-EDA structures by incorporating cross-linking agents provides inspiration for the design of next-generation high-performance anodes.

Graphene Nanoplatelet Exoskeleton on Polyurethane Foam to Produce Flame‐Retardant, Piezoresistive, and Electromagnetic Interference Shielding Surfaces

AbstractPolyurethane foam (PUF)’s porous structure, light weight, flexibility, and low‐cost properties make it useful in various cutting‐edge technologies. However, time‐consuming, costly, and complicated surface modification methods severely hinder its commercial applications. Herein, an ultrafast, simple, and cost‐effective surface modification method based on the evaporation of a low boiling point solvent to prepare a multifunctional graphene nanoplatelet (GNP)‐decorated PUF (GNP@PUF) is proposed. Due to the passive heat barrier of GNP sheets, the resulting sponge exhibits excellent flame retardancy by reducing the critical fire retardancy metrics, that is, peak heat release rate, total heat release, and total smoke release by 72%, 50%, and 81%, respectively. In addition, GNP@PUF can function as a piezoresistive sensor and electromagnetic interference (EMI)‐shielding material. As a piezoresistive sensor, it exhibits a wide‐compressive pressure (2.4–112 kPa)/strain (5–70%) range and ultra‐fast response/relaxation time (48/35 ms), wide‐stretching strain (5–100%) range, and it can detect minute human motions by being attached to different parts of the human body. Meanwhile, the composite foam displays good absorption‐dominant EMI shielding performance (≈38 dB), possibly due to conductive dissipation and multiple reflections/scattering of EM waves inside the 3D conductive graphene network. This study provides a simple coating technique for developing multifunctional lightweight foam materials.

Dried figs like nitrogen-doped graphene oxide anchored cobalt-doped Fe3O4 nanoparticle as sulfur host for high performance Li-S battery

Lithium-sulfur batteries (LSBs) represent a prospective energy storage device because of their low cost and high theoretical energy density. However, the performance of LSBs was largely constrained by the kinetics of polysulfides (LiPSs) conversion and shuttle effect. Thus, a metal-doped metal oxide is proposed as an efficient adsorbent and catalyst for LiPSs. We designed cobalt-doped Fe3O4 nano-catalysts which was in situ grown on the N-doped graphene conductive network as a multifunctional sulfur host. Evidenced by experimental characterization, it is demonstrated that due to the appropriate doping amount (EGO/Co-Fe3O4 (700)), the host exhibits efficient adsorption and rapid catalytic conversion of LiPSs. Compared with the undoped Co catalyst (S@EGO/Fe3O4), The S@EGO/Co-Fe3O4 (700) electrode possesses high initial discharge specific capacity (1488.4 mAh/g, 0.2 C), and superior cycle stability (900.8 mAh/g after 100 cycles). Impressive performances are also attained at lean electrolyte conditions (electrolyte-to-sulfur (E/S) ratio ∼ 7 μL mg−1).

Laser-Induced Graphene in Polyimide for Antenna Applications

Laser-induced graphene (LIG) has gained considerable attention recently due to its unique properties and potential applications. In this study, we investigated using LIG in polyimide (PI) as a material for antenna applications. The LIG-−PI composite material was prepared by a facile picosecond laser (1064 nm) irradiation process, which resulted in a conductive graphene network within the PI matrix. Furthermore, LIG formation was confirmed by Raman spectroscopy and sheet resistance measurements. Finally, a patch antenna from LIG with 2.45 GHz microwaves was simulated, produced and tested. These findings suggest that LIG−PI composites have great potential for use in high-frequency electronic devices and can provide a new avenue for the development of flexible and wearable electronics.

Facile fabrication of ultrathin graphene/cellulose composites with efficient electromagnetic interference shielding by spray deposition

Ultrathin electromagnetic interference shielding materials are commonly used to overcome electromagnetic pollution in applications including integrated and wearable electronics. This paper demonstrates a graphene composite with an ultrathin thickness of 43 μm manufactured using a facile and rapid spray deposition technique on a cellulose substrate. The graphene was highly oriented and densely stacked on the cellulose substrate by the spray deposition due to polyvinyl alcohol (PVA) and polyacrylic acid (PAA) introduced for increasing their self-adhesion and adhesion to the cellulose substrate. The interconnected graphene conductive networks on the cellulose were effectively formed, resulting in low electrical resistivity (0.003 Ω·m) and efficient electromagnetic shielding effectiveness (28.3 dB at the 10 GHz) of graphene/cellulose composites. It is expected that this research will be used for the effective development of electromagnetic shielding materials for multifunctional smart and wearable electronics.

Metal organic frameworks derived NiSe2 microspheres wrapped with graphene as a high-performance cathode for rechargeable magnesium batteries

Rechargeable magnesium batteries (RMBs) are suitable for large-scale energy storage, but the cathode materials are deficient. Herein, NiSe2 microspheres derived from Ni-metal organic frameworks (Ni-MOFs) and wrapped with reduced graphene oxide (NiSe2/rGO) are fabricated and used as RMB cathodes. The NiSe2 microspheres are composed of tiny nanoparticles and interweaved with conductive graphene network. The NiSe2/rGO cathode exhibits a capacity of 215.5 mAh g−1 at 50 mA g−1, a good rate capability of 66.8 mAh g−1 at 2.0 A g−1 and a stable cycling for 300 cycles. Further kinetic investigation indicates the graphene improves the activity of the tiny NiSe2 nanoparticles, enhancing the interphase charge transfer and the magnesium storage performance.

Self-Assembled Microfiber-Like Biohydrogel for Ultrasensitive Whole-Cell Electrochemical Biosensing in Microdroplets.

A novel microfiber-like biohydrogel was fabricated by a facile approach relying on electroactive bacteria-induced graphene oxide reduction and confined self-assembly in a capillary tube. The microfiber-like biohydrogel (d = ∼1 mm) embedded high-density living cells and activated efficient electron exchange between cells and the conductive graphene network. Further, a miniature whole-cell electrochemical biosensing system was developed and applied for fumarate detection under -0.6 V (vs Ag/AgCl) applied potential. Taking advantage of its small size, high local cell density, and excellent electron exchange, this microfiber-like biohydrogel-based sensing system reached a linear calibration curve (R2 = 0.999) ranging from 1 nM to 10 mM. The limit of detection obtained was 0.60 nM, which was over 1300 times lower than a traditional biosensor for fumarate detection in 0.2 μL microdroplets. This work opened a new dimension for miniature whole-cell electrochemical sensing system design, which provided the possibility for bioelectrochemical detection in small volumes or three-dimensional local detection at high spatial resolutions.

Constructing graphene conductive networks in manganese vanadate as high-performance cathode for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have been widely studied for their cheapness, safety, as well as high energy and power density. Electrode material plays a dominant role in the electrochemical properties of zinc-ion batteries. Reduced graphene oxide (rGO) can easily interact with compounds via π-π stacking for high-speed electron transport. In this study, The Mn-modified V6O13 material cathode was uniformly loaded onto the rGO conductive network. rGO can release the electron conduction process that limits the performance of the electrode material, and improves the rapid charge and discharge performance of the material. The results show that MnVO@rGO exhibits excellent energy storage properties with a high capacity of 360.3 mAh g−1 at a current density of 0.2 A g−1 in being used as the cathode material for AZIBs. More significantly, even with a current density expansion of a factor of 100, the MnVO@rGO//Zn battery still has a capacity of 88.9 mAh g−1 and a capacity retention rate of over 100% after 10,000 cycles. In addition, it has the maximal energy density of 260.0 Wh kg−1 and power density of 9113.7 W kg−1. This study provides an interesting idea for the development of electrode materials for zinc-ion batteries.

Iron-induced lattice distortion generally boots the graphene-supported nickel phosphide nanoparticles catalysis for efficient overall water splitting

Rational design of high-efficient, low-cost and stable bifunctional electrocatalysts is necessary but challenging for water electrolysis. Transition metal phosphides (TMPs) with rich redox properties are considered to be the most promising substitutes for noble-metal materials but with aggregation and poor intrinsic electrical conductivity. Herein, we report an ultra-fast and controllable microwave strategy for synthesizing Fe-doped nickel phosphide on reduced graphene oxide (Fe-Ni12P5/rGO) as a highly active bifunctional electrocatalyst for both hydrogen and oxygen evolution reactions (HER and OER). It is noteworthy that Fe introduction can significantly cause the lattice distortion of Ni12P5 and lead to the increase of electrocatalytic active sites and modulation of the electronic structure of each catalytic center. Benefiting from the highly active Fe-Ni12P5 nanoparticles and two-dimensional graphene conductive network, the as-fabricated Fe-Ni12P5/rGO shows excellent electrocatalytic activity for HER and OER with good stability. In addition, an overall water splitting device with Fe-Ni12P5/rGO as both the cathode and anode electrocatalysts requires only an extremely low cell voltage of 1.57 V to reach 10 mA cm−2, which is attractive among the latest research. This work provides a facile and effective approach for the design of high-performance transition metal-based electrocatalysts.