Thermal conductivity and permeability of consolidated expanded natural graphite treated with sulphuric acid

Wang, L.W.; Metcalf, Steven J.; Critoph, Robert E.; Thorpe, Roger; Tamainot-Telto, Zacharie

doi:10.1016/j.carbon.2011.06.093

Cited by 89 publications

(24 citation statements)

References 19 publications

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“…From Figure g, the graphene films reveal an exceptionally high thermal conductivity of 2292 ± 159 W m −1 K −1 at room temperature by considering the heat transport both on the sample surface and through the film thickness. The measured thermal conductivity is higher than graphite and high‐temperature‐ and high‐pressure‐treated graphene films, including graphite foil, expanded graphite, commercial pyrolytic graphite, HOPG, G‐O paper pressed, and heat treated at 2750 or 3000 °C, G‐O/CNT composite film or hydroxylated graphene film heat treated at 2800 °C (Figure h and Table S6, Supporting Information). The superb in‐plane thermal conduction properties have been attributed to the high‐quality defect‐free individual layers of graphene used in the layer‐by‐layer assembly of the films.…”

Section: Measured Interlayer Spacing Of Graphene Layers In Each Samplmentioning

confidence: 98%

Ultrastiff, Strong, and Highly Thermally Conductive Crystalline Graphitic Films with Mixed Stacking Order

et al. 2019

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A macroscopic film (2.5 cm × 2.5 cm) made by layer‐by‐layer assembly of 100 single‐layer polycrystalline graphene films is reported. The graphene layers are transferred and stacked one by one using a wet process that leads to layer defects and interstitial contamination. Heat‐treatment of the sample up to 2800 °C results in the removal of interstitial contaminants and the healing of graphene layer defects. The resulting stacked graphene sample is a freestanding film with near‐perfect in‐plane crystallinity but a mixed stacking order through the thickness, which separates it from all existing carbon materials. Macroscale tensile tests yields maximum values of 62 GPa for the Young's modulus and 0.70 GPa for the fracture strength, significantly higher than has been reported for any other macroscale carbon films; microscale tensile tests yield maximum values of 290 GPa for the Young's modulus and 5.8 GPa for the fracture strength. The measured in‐plane thermal conductivity is exceptionally high, 2292 ± 159 W m−1 K−1 while in‐plane electrical conductivity is 2.2 × 105 S m−1. The high performance of these films is attributed to the combination of the high in‐plane crystalline order and unique stacking configuration through the thickness.

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Section: Measured Interlayer Spacing Of Graphene Layers In Each Samplmentioning

confidence: 98%

Ultrastiff, Strong, and Highly Thermally Conductive Crystalline Graphitic Films with Mixed Stacking Order

et al. 2019

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“…The permeability perpendicular to the direction of compression vary in the range of 10 -11 to 10 -16 m 2 as the density increases from 111 to 539 kg/m 3 . As a type of heat transfer matrix the thermal diffusivity is about five times higher than that of pure aluminum [18].The development of the novel composite sorbents involves the following steps.…”

Section: Development Of Compact Composite Multi-salt Sorbentsmentioning

confidence: 99%

Solution to the sorption hysteresis by novel compact composite multi-salt sorbents

Gao

Wang

et al. 2017

Applied Thermal Engineering

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Two novel types of consolidated composite sorbents of NH 4 Cl/CaCl 2 /MnCl 2 and NH 4 Cl/CaCl 2 are developed by the matrix of expanded natural graphite treated with sulfuric acid (ENG-TSA). The Clapeyron curves and sorption / desorption properties of different sorbents are tested and compared under non-equilibrium conditions. Compared with single-salt sorbent, the multi-salt / ENG-TSA sorbents show the combining properties of each kind of metal chloride they contain. One novel phenomenon is discovered in the study is that the sorption hysteresis of single salts, which is regarded as one common phenomenon for chemisorption, can be changed by the composite sorbents of multi-salt. For the composite bi-salt sorbent of NH 4 Cl/CaCl 2 the sorption hysteresis is much less significant than the single metal chlorides of NH 4 Cl and CaCl 2 . For the tri-salt composite sorbent of NH 4 Cl/CaCl 2 /MnCl 2 the sorption hysteresis disappears. The reason is analyzed and it may be related to the resorption between the metal chlorides they contain, which leads to a reduction of reaction heat that is believed to be a typical reason for sorption hysteresis.

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“…The higher density of adsorbent is, the lower permeability and the higher thermal conductivity becomes. The anisotropic characteristics of thermal conductivity and permeability of consolidated ENG-TSA [17] and activated carbon/ENG-TSA composite adsorbent [18] have already been studied, and results indicate that direction for best heat and mass transfer performance is perpendicular to the compressing direction of composite adsorbent. In the experiment, only plate samples are utilized, and density is selected as 400 kg/m 3 uniformly illuminating in the sample surface, so that the temperature transient increases as the hot end of the one-dimensional heat conducts to the cold end propagation.…”

Section: Materials Characterization 21 Materialsmentioning

confidence: 99%

Investigation on non-equilibrium performance of composite adsorbent for resorption refrigeration

Jiang

Wang

Zhou

et al. 2016

Energy Conversion and Management

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The aims of this paper is to indicate that the non-equilibrium adsorption testing results is more suitable for prediction of the real refrigeration performance than equilibrium data. Therefore, a test unit is constructed to test the non-equilibrium performance of different composite adsorbents. The adsorption and desorption quantity are measured and calculated by smart differential pressure transmitter. The non-equilibrium adsorption performances of working pair of Manganese chloride-ammonia, Calcium chloride-ammonia and Ammonium chloride-ammonia are investigated respectively. Results show that hysteresis phenomena happens obviously in non-equilibrium desorption process, which is related with dual variables rather than single variable. Based on the testing results, resorption refrigeration performance is analyzed, in which Manganese chloride is used as high temperature salt (HTS), and Calcium chloride, Ammonium chloride are selected as low temperature salt (LTS) for comparison. Results show that the highest COP and SCP for resorption refrigeration are about 0.272 and 45.6 W/kg, respectively. Performance of Manganese chloride-Calcium chloride and Manganese chloride-Ammonium chloride working pairs are much lower when compared with theoretical data.

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Thermal conductivity and permeability of consolidated expanded natural graphite treated with sulphuric acid

Cited by 89 publications

References 19 publications

Ultrastiff, Strong, and Highly Thermally Conductive Crystalline Graphitic Films with Mixed Stacking Order

Ultrastiff, Strong, and Highly Thermally Conductive Crystalline Graphitic Films with Mixed Stacking Order

Solution to the sorption hysteresis by novel compact composite multi-salt sorbents

Investigation on non-equilibrium performance of composite adsorbent for resorption refrigeration

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