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The 2D materials exhibit numerous technological applications, but their scalable production is a core challenge. Herein, ball milling exfoliation in supercritical carbon dioxide (scCO2) and polystyrene (PS) is demonstrated to completely exfoliate hexagonal boron nitride nanosheets (BNNSs), graphene, molybdenum disulfide (MoS2), and tungsten disulfide (WS2). The exfoliation yield of 91%, 93%, 92%, and 92% and average aspect ratios of 743, 565, 564, and 502 for BNNSs, graphene, MoS2, and WS2, respectively, are achieved. Integrating exfoliated BNNSS in the polystyrene matrix, 3768 % thermal conductivity in the axial direction and 316% in the cross‐plane direction at 12 wt.% loading is increased. Also, the in‐plane and cross‐plane electrical conductivity of 6.3 × 10−4 S m−1 and 6.6 × 10−3 S m−1, respectively, and the electromagnetic interference (EMI) of 63.3 dB is achieved by exfoliated graphene nanosheets based composite. High thermal and electrical conductivities and EMI shielding are attributed to the high aspect ratio and ultrathin morphology of the exfoliated nanosheets, which exert high charge mobility and form better the percolation network in the composite films due to their high surface area. The process demonstrate herein can produce substantial quantities of diverse 2D nanosheets for widespread commercial utilization. [ABSTRACT FROM AUTHOR]

In the current work, novel graphene quantum dots (GQDs)-doped goethite (α-FeOOH) nanocomposites (GQDs/α-FeOOH) were prepared by following a feasible hydrolysis method and applied for ciprofloxacin (CIP) removal. Results showed that the CIP degradation efficiency was significant (93.73%, 0.0566 min−1) in the GQDs/α-FeOOH + H2O2 + Vis system using much lower amounts of H2O2 (0.50 mM), which is 3.9 times the α-FeOOH + H2O2 + Vis system. It was found that •OH, O 2 • − , and 1O2 were mainly responsible for CIP degradation in the GQDs/α-FeOOH photo-Fenton system. GQDs/α-FeOOH demonstrated broad-spectrum UV–vis-IR responsiveness in the degradation of ciprofloxacin as a function of the doping of GQDs. Additionally, GQDs/α-FeOOH showed outstanding durability (recyclability up to 3 cycles with a lower iron leaking amount, 0.020 mg L−1), a broad range of application pH, and a pretty acceptable catalytic efficacy in a variety of surface water matrices. Overall, GQDs/α-FeOOH have been shown to be an effective photocatalyst for the remediation of emerging contaminants via the workable exploitation of solar energy. [ABSTRACT FROM AUTHOR]

The multilayer hybrids of pristine graphene and polyaniline nanofiber were prepared via layer-by-layer vacuum filtration for making a high-performance supercapacitor. The specific capacitance of the hybrids electrode in the three-electrode system was measured as high as 565 F/g at a current density of 0.1 A/g, and the as-prepared supercapacitor exhibited high energy density and power density of 19.28 Wh/kg and 3.2 kW/kg, respectively. The synergistic effect of crosslinking polyaniline nanofiber network and pristine graphene intercalation not only provided larger specific areas exposed to electrolyte and improved the penetration rate of electrolyte but also improved the electrical conductivity as well as shorten the charge transmission pathways of electrons from electrode to current collector. The results demonstrate that the supercapacitor electrodes with excellent capacitive performance can be fabricated by constructing a multilayer hybrid of graphene and polyaniline nanofiber. [ABSTRACT FROM AUTHOR]

A simple, scalable approach is developed to fabricate a flexible hybrid paper electrode composed of the polyaniline/graphene and the carbon fiber (CF)-reinforced bacterial cellulose. The prepared hybrid paper presents high areal capacitance of 4.145 F cm−2 at 5 mA cm−2 and an extremely low sheet resistance of 29.7 Ω sq.−1. The CF endows the paper electrode remarkable foldability with no mechanical destruction. Even after being repeatedly bent 180° up to 1000 times, the initial capacitance can be retained up to 98%. A fabricated all-solid-state supercapacitor based on the resulting paper electrode has an excellent areal capacitance of 630 mF cm−2 and energy density of 2.8 mWh cm−3. The results confirm that this approach can fabricate the highly foldable and shape-tailorable energy storage devices and may have wide potential applications. [ABSTRACT FROM AUTHOR]

Drinking water fluoride pollution is a worldwide environmental problem imposing serious menace to human health. Goethite anchoring regenerated graphene oxide (α-FeOOH@rGO) nanocomposite was synthesized via facile one-step hydrolysis pathway with ferrous sulfate as starting material. Fluoride adsorption efficiencies in aqueous solution were also testified through batch adsorption experiments. α-FeOOH@rGO has good defluoridation ability in a wide range of pH and has a strong anti-interference ability in the presence of high concentration foreign anions. Pseudo-second-order adsorption kinetics and Langmuir adsorption isotherms are fitted well involved in fluoride adsorption process. The FTIR and XPS results prove that defluoridation proceeds through an ion-exchange mechanism with sulfate-bearing in α-FeOOH@rGO crystal structure. It would be useful for the purpose of environmental protection in design and improvement of α-FeOOH@rGO as a cost-effective anion-exchange adsorbent. [ABSTRACT FROM PUBLISHER]

Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe3O4 impregnated graphene oxide (Fe3O4@GO)-activated persulfate system (Fe3O4@GO+K2S2O8) was synthesized by following a sustainable protocol and was tested on real wastewater containing dye pollutants. In the presence of the PS-activated system, the degradation efficiency of Rhodamine B (RhB) was significantly increased to a level of ≈95% compared with that of Fe3O4 (≈25%). The influences of different operational parameters, including solution pH, persulfate dosage, and RhB concentration, were systemically evaluated. This system maintained its catalytic activity and durability with a negligible amount of iron leached during successive recirculation experiments. The degradation intermediates were further identified through reactive oxygen species (ROS) studies, where surface-bound SO4− was found to be dominant radical for RhB degradation. Moreover, the degradation mechanism of RhB in the Fe3O4@GO+K2S2O8 system was discussed. Finally, the results indicate that the persulfate-activated Fe3O4@GO catalyst provided an effective pathway for the degradation of dye pollutants in real wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Anisotropic hybrid carbon aerogel with an engineered architecture is fabricated. • Aerogel-based sensor exhibits superb mechanical and sensing performance. • Versatile applicabilities of prepared piezoresistive sensors are confirmed. • Applications in sound visualization, wearable devices, et al. are tested. Piezoresistive sensors are highly desired in a wide variety of fields in health monitoring, human–machine interaction, robot sensing, and so on. Developing engineering-architected piezoresistive sensors with biocompatibility, high sensitivity, and mechanical robustness is one of the hot research fields. Here, a high-performance hybrid carbon aerogel is constructed from bacterial cellulose, chitosan, graphene oxide, and graphene based on synergistic electrostatic interaction and hydrogen bonding through unidirectional freeze-casting and carbonization. The carbon aerogel, characterized by its unique lamellar and fibrous alternating structure, mirrors the stability of a well-constructed "bridge". In this analogy, the layer functions as a steady "girder", while the fiber emulates indispensable "stay cable". The ordered microstructure contributes to uniform stress transfer, yielding a carbon aerogel-based sensor that exhibits high piezoresistive linear sensitivity (150 kPa−1), outstanding mechanical stability (3000 compressing cycles), and a quick response/recovery time (120/90 ms). The piezoresistive sensor detects real-time human physiological signals and effectively distinguishes subtle and different acoustic signals, enabling sound visualization. Also, it can work well in extreme conditions (200 °C and −196 °C). The prepared piezoresistive sensor is expected to have versatile applications in next-generation spatial pressure monitoring, wearable electronics, and sound visualization. [ABSTRACT FROM AUTHOR]

Exfoliation of graphite has become a popular top-down method of producing graphene. However, it is still a challenging issue to prepare purified graphene because the exfoliated graphene was usually mixed with the un-exfoliated graphite. In this work, we investigated the isolation of the graphene and graphite by using supercritical CO 2 through Computational Fluid Dynamics (CFD) simulation and experimental. The Eulerian multiphase and standard k–ε turbulence models for CFD simulation were used to explore the influences of the pressure and the velocity of supercritical CO 2 , the geometry of the separation column, and the feeding amount of the mixture on the distribution of the graphene and graphite in the column. The isolation experiments were carried out based on the CFD simulation results, and the isolated graphene was characterized by Raman spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy. The results indicate that the purified graphene sheets can be obtained by supercritical CO 2 elutriation approach and the optimal experimental conditions were consistent with that obtained by CFD simulation. The graphene was isolated with graphite completely when the volume fraction of the mixture of the graphene and graphite was <20%, the pressure and the flow rate of supercritical CO 2 were 8 MPa and 0.2 m/s, respectively. The obtained graphene sheets mainly consisted of 3–5 layers. The CFD simulation is helpful in scale-up production of purified graphene by supercritical CO 2 elutriation technique. Unlabelled Image • The graphene in the mixture of the graphene and graphite was isolated by supercritical CO 2 elutriation technique. • The influences of process parameters on separation were investigated by CFD simulation and experiment. • The CFD simulation results were consistent with that obtained by experiment. • The purified graphene sheets consisted of 3–5 layers were obtained. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A free-standing PANI/G/MnO 2 paper electrode was constructed with exciting performance. • The electrode has a mass loading of 11.75 mg cm−2 and excellent flexibility stability. • The electrode has a sizeable areal capacitance of 3.5 F cm−2. • The all-solid-state supercapacitor was assembled with the ternary composite paper. • The supercapacitor exhibits a high energy density of 5.2 mW h cm−3 at 8.4 mW cm−3. Abstract Free-standing hierarchical polyaniline/graphene/MnO 2 (PANI/G/MnO 2) paper is well constructed using low-cost printing paper by a simple layer-by-layer in situ growth and vacuum filtration method. The PANI nanofiber was polymerized on cellulose fibers, and then the pristine graphene sheet was introduced to generate the polyaniline/graphene paper, whose surface was subsequently scattered with the formed MnO 2 nanoflowers through oxidation of the cellulose fiber and graphene. The PANI/G/MnO 2 paper possessing a mass loading of 11.75 mg cm−2 is of high flexibility and could serve as a working electrode without using any binder and conductive additives. The electrode shows a sizeable areal capacitance of 3.5 F cm-2 at 5 mA cm−2 and excellent cycling stability of 90% after 1000 bending cycles. All-solid-state supercapacitor assembled with the PANI/G/MnO 2 paper exhibits a high energy density of 5.2 mW h cm-3 at 8.4 mW cm-3. Eight supercapacitors connected in series can light a green light-emitting diode of 3 V. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A conductive paste has been formulated based on high pristine graphene loading. • The graphene paste shows good rheology and stability for screen-printing. • The screen-printed pattern has a high conductivity of 9 × 104 S/m and excellent mechanical flexibility. Abstract Graphene conductive pastes are poised to apply in making flexible electronics via a screen-printing way because of its excellent electrical and mechanical properties. In this paper, a new formulation of a pristine graphene-based paste was presented consisting of the conductive filler of graphene, a mixed solvent of terpineol, dipropylene glycol methyl ether, cyclohexanone, and the auxiliaries of ethyl cellulose, Span-85 and 1,4-butyrolactone. The paste containing 20 wt% of the graphene was prepared and showed excellent dispersibility and stability. The screen-printed patterns on a polyimide substrate achieved a high conductivity of 9 × 104 S/m and had excellent mechanical flexibility. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrated a simple and cost-effective method to produce graphene from graphite in ethanol using ultrasound assisted with curcumin. The influence of curcumin concentration, starting graphite amount, sonication power, and sonication time on the graphene concentration was studied schematically. The π-π interaction between curcumin and graphene, being confirmed by FTIR spectrum, facilitate the exfoliation of the graphite into graphene. The concentration of the graphene in the ethanol reached up to 1.44 mg mL −1 and the exfoliated suspension was relatively stable. The content of monolayer, bilayer, and multilayer in the exfoliated graphene suspension were 21%, 37%, and 42%, respectively. The as-prepared graphene sheets were free-defect. This novel approach may not only enable to exfoliate the graphite into graphene but also to make the graphene-curcumin hybrid which might find applications in pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pristine graphene quantum dots were prepared using a shear-mixer in supercritical CO 2. • The PL quantum yield achieved 8.6% measured against the standard quinine sulfate. • The mechanism for forming the PGQDs was elucidated. Abstract Graphene quantum dots exhibit unique electronic and optical properties due to their combined properties of quantum confinements and edge effects and have broad applications like bio-imaging, drug delivery, biosensors and photovoltaic applications. In this paper, we presented a facile and green preparation of pristine graphene quantum dots (PGQDs) from graphite using a shear-assisted supercritical CO 2 approach. The effects of the pressure, graphite amount, and shearing speed on the yield of the PGQDs were investigated. The fluorescence quantum yield of the PGQDs achieved 8.6%, and it was highly stable with blue light emission. The mechanism for forming the PGQDs was elucidated. [ABSTRACT FROM AUTHOR]

The hybrids of pristine graphene with polyaniline were synthesized by in situ polymerizations for making a high-performance supercapacitor. The formed high-ordered PANI nanocones were vertically aligned on the graphene sheets. The length of the PANI nanocones increased with the concentration of aniline monomer. The specific capacitance of the hybrids electrode in the three-electrode system was measured as high as 481 F/g at a current density of 0.1 A/g, and its stability remained 87% after constant charge-discharge 10000 cycles at a current density of 1 A/g. This outstanding performance is attributed to the coupling effects of the pristine graphene and the hierarchical structure of the PANI possessing high specific surface area. The unique structure of the PANI provided more charge transmission pathways and fast charge-transfer speed of electrons to the pristine graphene because of its large specific area exposed to the electrolyte. The hybrid is expected to have potential applications in supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

In this work, the preparation of the graphene/epoxy resin composite and its corrosion protection on the copper substrate were presented. The 1,8-diaminooctane-grafted-graphene (1,8-D-g-G) was synthesized using the carboxyl functional graphite and 1,8-diaminooctane by a one-pot process under ultrasonication in supercritical CO 2 . The structure and morphology of the as-prepared samples characterized by FTIR, XPS, TEM, AFM, and SEM confirmed that the graphite was exfoliated into the graphene and the latter reacted with the 1,8-diaminooctane via amidation to form the 1,8-D-g-G. The graphene/epoxy resin composite was readily achieved by the reaction of the epoxy resin with the 1,8-D-g-G. The electrochemical and salt spray tests were applied to assess the corrosion protection of the composite coating on the copper substrate. The results demonstrated that the composite exhibited excellent corrosion protection. Also, the mechanism of the co-occurred exfoliating process and the amidation reaction in one-pot under ultrasonication in supercritical CO 2 was explored. [ABSTRACT FROM AUTHOR]

Ultrasound coupled with supercritical CO 2 has become an important method for exfoliation of graphene, but behind which a peeling mechanism is unclear. In this work, CFD simulation and experiment were both investigated to elucidate the mechanism and the effects of the process parameters on the exfoliation yield. The experiments and the CFD simulation were conducted under pressure ranging from 8 MPa to 16 MPa, the ultrasonic power ranging from 12 W to 240 W and the frequency of 20 kHz. The numerical analysis of fluid flow patterns and pressure distributions revealed that the fluid shear stress and the periodical pressure fluctuation generated by ultrasound were primary factors in exfoliating graphene. The distribution of the fluid shear stress decided the effective exfoliation area, which, in turn, affected the yield. The effective area increased from 5.339 cm 3 to 8.074 cm 3 with increasing ultrasonic power from 12 W to 240 W, corresponding to the yield increasing from 5.2% to 21.5%. The pressure fluctuation would cause the expansion of the interlayers of graphite. The degree of the expansion increased with the increase of the operating pressure but decreased beyond 12 MPa. Thus, the maximum yield was obtained at 12 MPa. The cavitation might be generated by ultrasound in supercritical CO 2 . But it is too weak to exfoliate graphite into graphene. These results provide a strategy in optimizing and scaling up the ultrasound-assisted supercritical CO 2 technique for producing graphene. [ABSTRACT FROM AUTHOR]

The graphene-based composite paper with high thermal conductivity has attracted increasing attention for many potential applications in thermal management systems. In this paper, we reported a pristine-graphene based poly vinyl alcohol (PVA) composite film with high thermal conductivity. Firstly, a concentration of the PVA aqueous solution was mixed with the pristine-graphene made by a green way of supercritical CO 2 exfoliation to form the composite solution via non-covalent. Then, the composite solution was filtered through a porous cellulose filter membrane (CFM) by using a vacuum dead-end micro-filtration method. Finally, the film was obtained by peeling from CFM after drying. The characterization results indicate that the as-produced film had a layer-aligned structure and well flexibility. The graphene content of the films varied from 20 wt% to 65 wt%, and their thermal conductivity varied between 10.15 and 36.81 W/mk. The results of dissipating heat indicated the film with 20 μm thickness and 50 wt% graphene loading enabled the temperature of heat source to reduce by 8 °C, suggesting it can be potentially applied in thermal management system. [ABSTRACT FROM AUTHOR]

Fluoride adsorption capacity in water matrices depends highly on the properties of each component of the adsorption system, the most important one of these is the physchemical properties of the adsorbent. Nanoparticle Goethite anchored onto graphene oxide (FeOOH+Ac/GO) and rice spike-like Akaganeite anchored onto graphene oxide (FeOOH/GO) were synthesized via an in-situ hydrolysis procedure and compared their fluoride adsorption performances in order to address the effect of crystalline structure growth induced by acetate sodium (NaAc), one important organic ligand in water and soil. The morphology, crystallinity, surface functional groups, elemental compositions and atomic percentage of the two hybrid graphene based nanocomposites were characterized. In order to evaluate fluoride adsorption capacity and reveal fluoride adsorption mechanism, adsorption kinetics and dynamics, effects of pH, effects of co-existing anions and mass transfer coefficients were comprehensively investigated for two adsorbents in water matrix. The results show that organic ligands like acetate greatly modify the crystalline structure of iron (oxy)hydroxide (FeOOH), thus altered its fluoride adsorption performance and adsorption mechanism. It would be very important to know the interface behaviors of mineral mediated by natural organic ligands in water or soil matrices. [ABSTRACT FROM AUTHOR]

A green and scalable method was presented for the production of pristine graphene by the exfoliation of graphite using a shear mixer in supercritical CO 2 . The resulting graphene flakes were characterized by transmission electron microscopy, Raman spectroscopy and atomic force microscopy. The synergistic effects of the fluid dynamic force coupled with the supercritical CO 2 actualized the exfoliation of graphite into graphene. The total exfoliation yield reached 63.2%. Up to 79% of the produced graphene was less than five layers, of which monolayer, bilayer and trilayer represented 27%, 25% and 14%, respectively. The average lateral size of the resulting graphene was 5 μm. The Raman spectrum reveals that the graphene was defect free. The prepared graphene was utilized to fabricate flexible, transparent and conductive films on a PET substrate through a vacuum filtration and dry transfer method. The transparency of the film reached 83%, the resistance was 0.83 kΩ/sq, and there was minimal variation, even after the film was bent more than 500 cycles. [ABSTRACT FROM AUTHOR]

Graphene-based materials with novel properties are widely applied in energy storage fields. In the last two decades, various methods have been used to prepare graphene-based materials, in which the supercritical fluid (SCF) technology exhibits unique advantages. This review summarizes the advantages of SCF technology in preparing graphene-based materials and their applications in energy storage systems. Firstly, the fundamental properties of graphene, graphene oxide (GO), and reduced graphene oxide (rGO) are introduced. Then, the SCF exfoliation, deposition, doping, and drying process in graphene-based materials are presented. In the last section, the performance of graphene-based materials in supercapacitors, Lithium-ion batteries, Sodium-ion batteries, fuel cells, and thermal storage systems are overviewed, respectively. This review reveals that the SCF technology can produce graphene-based materials with unique properties and would promote their applications in energy storage. [Display omitted] • Supercritical fluid-assisted methods to prepare graphene-based materials were reviewed. • Applications of graphene-based materials in energy storage were reviewed. • Supercapacitors, lithium-ion batteries, and new energy storage were mainly presented [ABSTRACT FROM AUTHOR]

[Display omitted] • High capacitance carbon fiber/graphene/bacterial cellulose/polyaniline electrode. • Oxygen plasma modification improved surface hydrophilicity and polyaniline load. • Two-stage conductive network greatly improved carrier transfer rate. In this paper, a novel structured carbon fiber/graphene/bacterial cellulose/polyaniline composite with high capacitive performance was fabricated. Graphene and carbon fiber modified with oxygen plasma formed a two-stage conductive network in composite supplying more pathways for charge carrier, thus improving charge carrier transfer performance. Oxygen plasma improved the hydrophilicity as well as produced more active sites on the surface of carbon fiber and graphene, leading to a higher PANI loading amount. The as-prepared composite presented high PANI loading amount of 6.95 mg/cm2 and areal capacitance of 5.44F/cm2 at the current density of 5 mA/cm2. [ABSTRACT FROM AUTHOR]

A continuous supercritical solvothermal technique was developed for synthesizing TiO 2 –graphene hybrids, with the pristine graphene sheets used as the crystallization sites and the TiO 2 nanoparticles crystallized on the graphene, forming the hybrids simultaneously. The structure and morphology of the fabricated hybrids were characterized via X-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy. The uniform hybrids were obtained at different concentrations of graphene while the temperature, pressure and resident time were fixed at 350 °C, 23 MPa, and 30 s, respectively. The TiO 2 particles formed on the hybrids were approximately 5–10 nm in size and dispersed uniformly. Compared with the pure TiO 2 and the commercial P25, the photocatalytic efficiency of the hybrids was greatly enhanced. The hybrid enabled methyl orange dye to degrade almost completely in 180 min, while only 78% and 82% of the methyl orange dye was degraded separately by the pure TiO 2 and P25. This enhanced photocatalytic performance of the hybrids is attributed to the well distributed-TiO 2 and the rapid transfer of the photo-generated electrons from the surface of the catalyst to the graphene, thereby preventing a photo-generated electron–hole recombination. [ABSTRACT FROM AUTHOR]

Highlyconductive pristine graphene electrodes were fabricatedby inkjet printing using ethyl cellulose-stabilized ink prepared frompristine graphene. Pristine graphene was generated by exfoliationfrom graphite using ultrasound-assisted supercritical CO2. The ink, at concentrations up to 1 mg/mL, was stable for more than9 months and had compatible fluidic characteristics for efficientand reliable inkjet printing. The inkjet printing patterns of thegraphene on diverse substrates were uniform and continuous. After30 printing passes and annealing at 300 °C for 30 min, the printedfilms developed a high conductivity of 9.24 × 103S/m.The resistivity of the printed electrodes on the flexible substratesincreased by less than 5% after 1000 bending cycles and by 5.3% undera folding angle of 180°. The presented exfoliated pristine grapheneand the corresponding efficient methods for formulating the ink andfabricating conductive electrodes are expected to have high potentialin applications involving graphene-based flexible electronic devices. [ABSTRACT FROM AUTHOR]

Highlights: [•] Preparation of graphene by ultrasonic in supercritical CO2 is developed. [•] Single- and few-layer graphene sheets are exfoliated from graphite directly. [•] Ultrasonic power affects the number of graphene layers and their lateral sizes. [•] As-exfoliated graphenes heighten electrochemical performance of LiFePO4 cathode. [•] The specific capacity of the LiFePO4/graphene composite cathode achieves 160mAh/g. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop industrially scalable methods to produce defect-free graphene to meet the requirement of graphene from lab to commercial applications. In this paper, a ball-milling in series with a shear-mixing exfoliation technique in supercritical CO 2 was developed. Graphite was pretreated by ball-milling in supercritical CO 2 , and the exfoliated sheets with smaller lateral sizes and numerous crevices on their edges were elutriated into a shear-mixing vessel by supercritical CO 2 simultaneously to inhibit over crushing. Whereafter, the freshly exfoliated sheets with crevices were further exfoliated into few-layer graphene without aggregation. 90% of the obtained graphene was less than five layers, and the processing capacity of 40 g for one batch increased 40–100 times compared with the previously reported method. The electrical conductivity of 3.25 × 105 S/m of the flexible graphene film on PVDF substrate demonstrates the excellent electrical performance of the obtained graphene. [Display omitted] • Continuous graphene exfoliation system via ball-milling and shear-mixing in SC-CO 2. • SC-CO 2 ball-milling pretreatment producing numerous crevices on graphite edges. • CO 2 elutriation separation inhibits over crushing and promoting exfoliation. • High-quality graphene was produced continuously with a single batch output of 40 g. • Obtained graphene showed excellent electrical conductivity of 3.25 × 105 S/m. [ABSTRACT FROM AUTHOR]