Increasing both the electromagnetic shielding and thermal conductive properties of three-dimensional graphene-CNT-SiC hybrid materials

During the operation of electronic devices,a considerable amount of heat and electromagnetic radiation is emitted.Therefore,the investigation of materials with electromagnetic shielding and thermal management abilities has significant importance.Hybrid materials of three-dimensional graphene networks containing both carbon nanotubes(CNTs)and SiC whiskers(3D graphene-CNT-SiC)were synthesized.Using an aqueous-phase reduction method for the self-assembly of the graphene oxide,a three-dimen-sional porous graphene structure was fabricated.SiC whiskers,inserted between the graphene layers,formed a framework for longit-udinal thermal conduction,while CNTs attached to the SiC surface,created a dendritic structure that increased the bonding between the SiC whiskers and graphene,improving dielectric loss and thermal conductivity.It was found that the thermal conductivity of the hybrid material reached 123 W·m^(-1)·K^(-1),with a shielding effectiveness of 29.3 dB when the SiC addition was 2%.This result indic-ates that 3D graphene-CNT-SiC has excellent thermal conductivity and electromagnetic shielding performance.

Highly Thermo-Conductive Three-Dimensional Graphene Aqueous Medium

Highly thermo-conductive aqueous medium is a crucial premise to demonstrate high-performance thermal-related applications.Graphene has the diamond comparable thermal conductivity,while the intrinsic two-dimensional reality will result in strong anisotropic thermal conductivity and wrinkles or even crumples that significantly sacrifices its inherent properties in practical applications.One strategy to overcome this is to use three-dimensional(3D)architecture of graphene.Herein,3D graphene structure with covalent-bonding nanofins(3D-GS-CBF)is proposed,which is then used as the filler to demonstrate effective aqueous medium.The thermal conductivity and thermal conductivity enhancement efficiency of 3D-GS-CBF(0.26 vol%)aqueous medium can be as high as 2.61 W m-1 K-1 and 1300%,respectively,around six times larger than highest value of the existed aqueous mediums.Meanwhile,3D-GS-CBF can be stable in the solution even after 6 months,addressing the instability issues of conventional graphene networks.A multiscale modeling including non-equilibrium molecular dynamics simulations and heat conduction model is applied to interpret experimental results.3D-GS-CBF aqueous medium can largely improve the solar vapor evaporation rate(by 1.5 times)that are even comparable to the interfacial heating system;meanwhile,its cooling performance is also superior to commercial coolant in thermal management applications.

Synthesis and electrochemical properties of three-dimensional graphene/polyaniline composites for supercapacitor electrode materials

To improve the specific capacitance and rate capability of electrode material for supercapacitors, a three-dimensional graphene/polyaniline （3DGN/PANI） composite is prepared via in situ polymerization on GN hydrogel. PANI grows on the GN surface as a thin film, and its content in the composite is controlled by the concentration of the reaction monomer. The specific capacitance of the 3DGN/PANI composite containing 10 wt% PANI reaches 322.8 F.g-1 at a current density of 1 A.g-1, nearly twice as large as that of the pure 3DGN （162.8 F.g-1）. The capacitance of the composite is 307.9 F.g-1 at 30 A.g-1 （maintaining 95.4%）, and 89% retention after 500 cycles. This study demonstrates the exciting potential of 3DGN/PANI with high capacitance, excellent rate capability and long cycling life for supercapacitors.

Preparing three-dimensional graphene architectures: Review of recent developments

The recent development of synthesis processes to assemble graphene sheets into porous three-dimensional （3D）macroscopic structures are reviewed, including our efforts on 3D graphene structures. Mechanisms for building 3D graphene architectures and their composite materials are also summarized. The functional systems based on 3D graphene architectures provide a significant enhancement in the efficacy due to their unique structures and properties.

Dynamic surface wettability of three-dimensional graphene foam

In this work, three-dimensional graphene foams （GFs） are synthesized and characterized by scanning electron micro- scope （SEM） and Raman spectroscopy. The SEM images indicate that after the growth of graphene, the graphene covers the surface of nickel （Ni） foam uniformly. Raman spectra show that the percentages of monolayer, bilayer, trilayer, and multilayer graphenes are - 58%, - 32%, - 8%, and ,.o 2%, respectively. The contact angle （CA） （-- 12°） of water droplet （3 p-L） on GF is found to be larger than that on Ni foam （,- 107°）, indicating that graphenes have changed the surface wettability of the Ni foam. Meanwhile, the dynamic characteristics of CA of water droplet on GF are different from those on Ni foam. The mechanisms for different behaviors are discussed, which are attributed to volatilization and seepage of water droplets.

Rational design of Co nano-dots embedded three-dimensional graphene gel as multifunctional sulfur cathode for fast sulfur conversion kinetics

Lithium-sulfur(Li-S)batteries hold great promises to serve as next-generation energy storage devices because of their high theoretical energy density and environmental benignity.However,the shuttle effect of the soluble lithium polysulfides(LiPS)and intrinsic insulating nature of sulfur lead to low sulfur utilization and coulombic efficiency,leading to poor cycling performance.The impeded charge transportation and retard LiPS catalytic conversion also endows the Li-S batteries with sluggish redox reaction,leading to unsatisfied rate capability.In this study,Co-based MOF material ZIF-67 is used as the precursor to prepare Co nano-dots decorated three-dimensional graphene aerogel as sulfur immobilizer.This porous architecture establishes a highly conductive interconnected framework for fast charge/mass transportation.The exposed Co nano-dots serve as active sites to strongly trap LiPS,which endows CoNDs@G with low decomposition energy barrier for fast LiPS conversion reaction and promote the completely Li2 S catalytic transformation.Li-S cells based on the Co-NDs@G cathode exhibits excellent cyclability and a high capacity retention rate of 91.1%in 100 cycles.This strategy offers a new direction to design sulfur immobilizer for accelerated LiPS conversion kinetics of Li-S batteries.

Design and construction of three-dimensional graphene/conducting polymer for supercapacitors

Three-dimensional graphene/conducting polymer（3DGCP） composites have received significant attention in recent years due to their unique structures and promising applications in energy storage.With the structural diversity of graphene and π-functional conducting polymers via rich chemical routes,a number of 3DGCP composites with novel structures and attractive performance have been developed.Particularly,the hierarchical porosity,the interactions between graphene and conducting polymers as well as the their synergetic effects within 3DGCP composites can be well combined and elaborated by various synthetic methods,which made 3DGCP composites show unique electrochemical properties and significantly improved performance in energy storage fields compared to other graphenebased composites.In this short review,we present recent advances in 3DGCP composites in developing effective strategies to prepare 3DGCP composites and exploring them as a unique platform for supercapacitors with unprecedented performance.The challenges and future opportunities are also discussed for promotion of further study.

Three-dimensional graphene and its composite for gas sensors

As a two-dimensional(2D)material,graphene shows excellent advantages in the field of gas sensors due to its inherent large specific surface area and unique electrical properties.However,in the practical application of gas detection,graphene sheet is easy to form irreversible agglomeration and has some limitations such as low sensitivity,long response time and slow recovery speed,which greatly reduce its gas sensing performance.As a gas sensing material,three-dimensional(3D)porous graphene has been extensively studied in recent years owing to its larger specific surface area and stable structure.In order to synthesize graphene with different three-dimensional structures,many methods have been developed.Herein,the synthesis and assembly of three-dimensional graphene and its composites were reviewed,with emphasis on the application of three-dimensional graphene and its composites in the field of gas sensors.The challenges and development prospects of three-dimensional graphene materials in the application of gas sensors were briefly described.

Three-dimensional MoS_2/reduced graphene oxide aerogel as a macroscopic visible-light photocatalyst

Photocatalysis is regarded as an ideal technology for solving the urgent environmental and energy issues that we face today.Among the reported photocatalysts,molybdenum disulfide（MoS2） is very promising for applications in hydrogen production and pollutant photodegradation.However,its lack of active sites and the difficulty of recovering catalysts in powder form have hindered its wide application.Here,we report the successful preparation of a macroscopic visible-light responsive MoS2/reduced graphene oxide（MoS2/RGO） aerogel.The obtained MoS2/RGO aerogel exhibits enhanced photocatalytic activity towards hydrogen production and photoreduction of Cr（Ⅵ） in comparison with the MoS2 powder.In addition,the low density（56.1 mg/cm^3） of the MoS2/RGO aerogel enables it to be used as an efficient adsorption material for organic pollutants.Our results demonstrate that this very promising multifunctional aerogel has potential applications in environmental remediation and clean energy production.

Vertical crosslinking MoS_2/three-dimensional graphene composite towards high performance supercapacitor

Molybdenum disulfide（MoS2） has been stimulated in extensive researches due to its layered structure and the potential as an electrochemical energy material. However, the effects on electrochemical performance of concentration of MoS2 are rarely mentioned. In this paper, the effects of different concentrated layered MoS2 on the morphology and electrochemical properties of the composite of MoS2 and three-dimensional graphene（MoS2/3DG） were discussed. The results show that layered MoS2 was successfully compounded to 3DG and formed a vertical crosslinking structure. It can be observed that MoS2 nanosheets are vertically loaded on the inner and outer surface of graphee when the concentration of MoS2 is 0.20 mg/L. The specific capacitance of composite（MoS2（0.20 mg/L）/3 DG）reaches 2182.33 mF/cm^2 at the current density of 1 mA/cm^2, and the specific capacitance remains 116.83% after 5000 cycles. When the current density increased 100 times（from 1 mA/cm^2 to 100 mA/cm^2）, the specific capacitance retains 78.9%. Meanwhile, the hybrid energy storage devises can deliver an energy density of 130.34 Wh/m^2. The superior electrochemical properties are attributed to the synergistic effect of MoS2 and 3DG. Therefore, the material has a potential application on supercapacitor electrode material.

Flexible Graphene Field‑Effect Transistors and Their Application in Flexible Biomedical Sensing

Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.

Advances in Graphene‑Based Electrode for Triboelectric Nanogenerator

With the continuous development of wearable electronics,wireless sensor networks and other micro-electronic devices,there is an increasingly urgent need for miniature,flexible and efficient nanopower generation technology.Triboelectric nanogenerator(TENG)technology can convert small mechanical energy into electricity,which is expected to address this problem.As the core component of TENG,the choice of electrode materials significantly affects its performance.Traditional metal electrode materials often suffer from problems such as durability,which limits the further application of TENG.Graphene,as a novel electrode material,shows excellent prospects for application in TENG owing to its unique structure and excellent electrical properties.This review systematically summarizes the recent research progress and application prospects of TENGs based on graphene electrodes.Various precision processing methods of graphene electrodes are introduced,and the applications of graphene electrode-based TENGs in various scenarios as well as the enhancement of graphene electrodes for TENG performance are discussed.In addition,the future development of graphene electrode-based TENGs is also prospectively discussed,aiming to promote the continuous advancement of graphene electrode-based TENGs.

Application of nanotechnology to dentistry:Impact of graphene nanocomposites on clinical air quality

Concerns about air quality in dental clinics where aerosol generation during procedures poses significant health risks,have prompted investigations on advanced disinfection technologies.This editorial describes the strengths and limitations of ventilation and aerosol control measures in dental offices,especially with respect to the use of graphene nanocomposites.The potential of graphene nanocomposites as an innovative solution to aerosol-associated health risks is examined in this review due to the unique properties of graphene(e.g.,high con-ductivity,mechanical strength,and antimicrobial activity).These properties have produced promising results in various fields,but the application of graphene in dentistry remains unexplored.The recent study by Ju et al which was published in World Journal of Clinical Cases evaluated the effectiveness of graphene-based air disinfection systems in dental clinics.The study demonstrated that graphene-based disinfection techniques produced significant reductions in suspended particulate matter and bacterial colony counts,when co-mpared with traditional methods.Despite these positive results,challenges such as material saturation,frequency of filter replacement,and associated costs must be addressed before widespread adoption of graphene-based disinfection techniques in clinical practice.Therefore,there is need for further research on material structure optimization,long-term safety evaluations,and broader clinical applications,in order to maximize their positive impact on public health.

Graphene Aerogel Composites with Self‑Organized Nanowires‑Packed Honeycomb Structure for Highly Efficient Electromagnetic Wave Absorption

With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.

Use of graphene nanocomposites for air disinfection in dental clinics:A game-changer in infection control

This manuscript features the promising findings of a study conducted by Ju et al,who used graphene nanocomposites for air disinfection in dental clinics.Their study demonstrated that,compared with conventional filters,graphene nanocom-posites substantially improved air quality and reduced microbial contamination.This manuscript highlights the innovative application of graphene materials,emphasizing their potential to enhance dental clinic environments by minimizing secondary pollution.On the basis of the unique antimicrobial properties of gra-phene and the original study’s rigorous methodology,we recommend using gra-phene nanocomposites in clinical settings to control airborne infections.

Three-dimensional graphene membrane cathode for high energy density rechargeable lithium-air batteries in ambient conditions

Lithium-air batteries have attracted significant interest for applications in high energy density mobile power supplies, yet there are considerable challenges to the development of rechargeable Li-air batteries with stable cycling performance under ambient conditions. Here we report a three-dimensional （3D） hydrophobic graphene membrane as a moisture-resistive cathode for high performance Li-air batteries. The 3D graphene membrane features a highly interconnected graphene network for efficient charge transport, a highly porous structure for efficient diffusion of oxygen and electrolyte ions, a large specific surface area for high capacity storage of the insulating discharge product, and a network of highly tortuous hydrophobic channels for O2/H20 selectivity. These channels facilitate 02 ingression while retarding moisture diffusion and ensure excellent charge/ discharge cycling stability under ambient conditions. The membrane can thus enable robust Li-air batteries with exceptional performance, including a maximum cathode capacity that exceeds 5,700 mAh/g and excellent recharge cycling behavior （〉2,000 cycles at 140 mAh/g, and 〉100 cycles at 1,400 mAh/g）. The graphene membrane air cathode can deliver a lifetime capacity of 100,000-300,000 mAh/g, comparable to that of a typical lithium ion battery cathode. The stable operation of Li-air batteries with significantly improved single charge capacities and lifetime capacities comparable to those of Li-ion batteries may offer an attractive high energy density storage alternative for future mobile power supplies. These batteries may provide much longer battery lives and greatly reduced recharge frequency.

Environmental application of three-dimensional graphene materials as adsorbents for dyes and heavy metals: Review on ice-templating method and adsorption mechanisms

The remediation of wastewater requires treatment technologies which are robust, efficient,simple to operate and affordable such as adsorption. Lately, three-dimensional(3D)graphene based materials have attracted significant attention as effective adsorbents for wastewater treatment. The intrinsic properties of 3D graphene structure such as large surface area and interconnected porous structure can facilitate the transport of pollutants into the 3D network and provide abundant active sites for trapping the pollutants. For the synthesis of 3D graphene structure, ice-templating is commonly practiced due to its facile steps, cost effectiveness and high scalability potential. This review covers the icetemplating fabrication technique for 3D graphene based materials and their application as adsorbents in eliminating dyes and heavy metals from aqueous media. The assembly mechanisms of the ice-templating fsynthesis are comprehensively discussed. Further discussion on the fundamental principles, critical process parameters and characteristics of ice-templated 3D graphene structures is also included. A thorough review on the mechanisms for batch adsorption of dyes and heavy metals is presented based on the structures and properties of the 3D graphene materials. The review further evaluates the dynamic adsorption in packed columns and the regeneration of 3D graphene based materials.

Three-dimensional graphene framework with ultra-high sulfur content for a robust lithium-sulfur battery

Lithium-sulfur batteries can deliver significantly higher specific capacity than standard lithium ion batteries, and represent the next generation of energy storage devices for both electric vehicles and mobile devices. However, the lithium-sulfur technology today is plagued with numerous challenges, including poor sulfur conductivity, large volumetric expansion, severe polysulfide shuttling and low sulfur utilization, which prevent its wide-spread adoption in the energy storage industry. Here we report a freestanding three-dimensional （3D） graphene frame- work for highly efficient loading of sulfur particles and creating a high capacity sulfur cathode. Using a one-pot synthesis method, we show a mechanically robust graphene-sulfur composite can be prepared with the highest sulfur weight content （90% sulfur） reported to date, and can be directly used as the sulfur cathode without additional binders or conductive additives. The graphene-sulfur composite features a highly interconnected graphene network ensuring excellent conductivity and a 3D porous structure allowing efficient ion transport and accommodating large volume expansion. Additionally, the 3D graphene framework can also function as an effective encapsulation layer to retard the polysulfide shuttling effect, thus enabling a highly robust sulfur cathode. Electrochemical studies show that such composite can deliver a highest capacity of 969 mAh-g-1, a record high number achieved for all sulfur cathodes reported to date when normalized by the total mass of the entire electrode. Our studies demonstrate that the 3D graphene framework represents an attractive scaffold material for a high performance lithium sulfur battery cathode, and could enable exciting opportunities for ultra-high capacity energy storage applications.

Flexible Three-Dimensional Graphene Hydrogels with Superior Conductivity and Excellent Electrochemical Performance for Supercapacitor Electrodes

Three-dimensional porous graphene hydrogels have been prepared by a green and facile but very efficient ap- proach using glucose as an assistant. Based on a one-step hydrothermal reaction with optimal experimental condi- tions such as the reaction time and temperature, the graphene hydrogels exhibit a superior electrical conductivity （95.3 S/m） and can be used as supercapacitor electrode without any binder or conducting additives but showing a high specific capacitance of 384.6 F/g at a current density of 1 A/g. The results show that addition of glucose can not only greatly decrease the reaction temperature but also shorten the reaction time. The superior performance of the three-dimensional porous graphene hydrogels as electrode for supercapacitor suggests its promising potentials in the field of energy storage devices.

Fiber-reinforced Three-dimensional Graphene Aerogels for Electrically Conductive Epoxy Composites with Enhanced Mechanical Properties

To enhance the mechanical properties of three-dimensional graphene aerogels with aramid fibers, graphene/organic fiber aerogels are prepared by chemical reduction of graphene oxide in the presence of organic fibers of poly（p-phenylene terephthalamide） （PPTA） and followed by freeze-drying. Thermal annealing of the composite aerogels at 1300℃ is adopted not only to restore the conductivity of the reduced graphene oxide component but also to convert the insulating PPTA organic fibers to conductive carbon fibers by the carbonization. The resultant graphene/carbon fiber aerogels （GCFAs） exhibit high electrical conductivities and enhanced compressive properties, which are highly efficient in improving both mechanical and electrical performances of epoxy composites. Compared to those of neat epoxy, the compressive modulus, compressive strength and energy absorption of the electrically conductive GCFA/epoxy composite are significantly increased by 60%, 59% and 131%, respectively.