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Properties and microstructures of A3-3 matrix graphite for pebble fuel elements after high temperature purification at different temperatures
ZHOU Xiang-wen, ZHANG Kai-hong, YANG Yang, WANG Lei, ZHANG Jie, LU Zhen-ming, LIU Bing, TANG Ya-ping
 doi: 10.1016/S1872-5805(21)60048-3
Abstract(116) HTML(56) PDF(10)
Matrix graphite (MG) was purified by high temperature purification (HTP), and their properties and microstructures were measured and analyzed to investigate the effect of HTP temperature on the property improvement of A3-3 MG as a pebble fuel element, and to optimize the purification temperature. Results showed that all the properties of MG specimens purified at temperatures from 1600 to 1900 ℃ met the technical requirements. X-ray diffraction analysis results showed that the microstructures of MG after HTP were significantly improved. With increasing the purification temperature from 1600 to 1900 ℃, MG gradually became ordered, the microstructures became better gradually for improving the comprehensive performance. The ash content decreased abruptly after HTP at 1600 ℃, but changed little when the purification temperature rose from 1600 to 1900 ℃. The microstructure improvement at high temperatures played a decisive role in increasing the oxidative corrosion resistance of MG. Therefore, HTP is very important and necessary, and cannot be canceled in the production of pebble fuel elements. This study provides an important reference to determine an optimal HTP temperature of pebble fuel elements for improving the production efficiency and reducing production cost in the commercial production of pebble fuel elements in the future.
A review of graphene-based films for heat dissipation
LI Hao-liang, XIAO Shu-ning, YU Hong-liu, XUE Yu-hua, YANG Jun-he
 doi: 10.1016/S1872-5805(21)60092-6
Abstract(2) HTML(1) PDF(1)
Graphene, owing to its outstanding thermal and electrical conductivity, has been regarded as one of the promising substitutes for heat dissipation or electromagnetic shielding and attracted widespread attention recently. Here, we attempt to summarize the current state of reduced graphene oxide films, graphene films and graphene-based composite films for thermal management, including the preparation and the applications. Additionally, the key factors that determine the thermal conductive performance of graphene films are also discussed to figure out the main challenges, especially in the scalable manufacturing of graphene-based films in the near future.
A review on vertically aligned carbon nanotube arrays and carbon/carbon composites: Fabrication, thermal conduction properties and applications in thermal management
DONG Zhi-jun, SUN Bing, ZHU Hui, YUAN Guan-ming, LI Bao-liu, GUO Jian-guang, LI Xuan-ke, CONG Ye, ZHANG Jiang
 doi: 10.1016/S1872-5805(21)60090-2
Abstract(26) HTML(2) PDF(16)
The development of modern technology has put forward higher and more urgent needs for thermal management materials. Due to their low thermal expansion coefficient, excellent thermal conduction and high-temperature resistance, vertically aligned carbon nanotube arrays and carbon/carbon composites have aroused extensive interests as ideal lightweight and stable thermal management materials. Here, we firstly introduce the thermal conducting mechanism of carbon materials. Then, we present the general fabrication methods, the main factors affecting thermal conductivity of vertically aligned carbon nanotube arrays and carbon/carbon composites as well as their applications in thermal management. The preparation-structure-performance relationships are outlined and the strategies for achieving high thermal conductivity are summarized. Finally, critical consideration on the challenges and prospects in thermal management applications of vertically aligned carbon nanotube arrays and carbon/carbon composites are presented.
A review of three-dimensional graphene networks for thermally conductive polymer composites: Constructions and applications
WU Ni, CHE Sai, LI Hua-wei, WANG Chao-nan, TIAN Xiao-juan, LI Yong-feng
 doi: 10.1016/S1872-5805(21)60089-6
Abstract(25) HTML(2) PDF(7)
As the power consumption and heat generation of electronic devices continue to increase, higher demands are therefore placed on thermal management materials for heat dissipation. Graphene has been widely used as the thermal conductive filler to improve the thermal conductivity of polymers. However, the poor dispersibility of graphene nanoplates in polymers dramatically limits their practical applications in thermal management. A promising strategy to increase the thermal conductivity of polymer composites is to construct the interconnected three-dimensional graphene networks. This review summarizes the recent advancements in the construction and applications of three-dimensional graphene-based polymer composites (3D GPCs). The approaches to enhance the thermal conductivity of 3D GPCs are presented. The current challenges and our perspectives in the preparation and applications of 3D GPCs are proposed.
Thermal conductivity of graphite nanofiber electrospun from graphene-oxide-doped polyimide
YUAN Ze-zheng, CHEN Wei, SHI Yun-kai, CHU Xiao-dong, HUANG Zheng-hong, GAN Lin, LI Jia, HE Yan-bing, LI Bao-hua, KANG Fei-yu, DU Hong-da
 doi: 10.1016/S1872-5805(21)60077-X
Abstract(80) HTML(19) PDF(6)
Aromatic polyimide (PI)-based graphite nanofibers are obtained from the graphitization of graphene oxide (GO)-doped electrospun PI nanofibers. GO improves the PI molecular orientation, crystalline structure and thermal conductivity of PI graphite nanofibers. The degree of PI molecular orientation of the nanofibers is enhanced during fiber preparation by GO. The improvement of molecular orientation facilitates the increase in the thermal conductivity of the graphite nanofibers. As the addition of only 0.1% GO can lead to an apparent increase in the thermal conductivity of PI-based graphite nanofibers. The effect of GO on the thermal conductivity is not by itself, but by the improvement in PI molecular orientation and its role as nucleation centers in graphitization. This approach and the resulting high thermal conductivity materials show great potential for practical applications.
A comprehensive review of three-dimensional graphene for thermal management and electromagnetic protection
JIA Hui, LIANG Lei-Lei, LIU Dong, WANG Zheng, LIU Zhuo, XIE Li-Jing, TAO Ze-Chao, KONG Qing-Qiang, CHEN Cheng-Meng
 doi: 10.1016/S1872-5805(21)60088-4
Abstract(15) HTML(3) PDF(4)
The three-dimensional (3D) graphene network structure has aroused great interest because it can effectively solve the agglomeration problem of graphene powder and improve its utilization efficiency. Simultaneously, such a structure possesses many advantages of a porous structure, lightweight, high thermal conductivity and superior electrical conductivity, which is widely used in thermal management and electromagnetic protection fields. To fully understand the 3D graphene networks, herein, we summarize different preparation strategies and properties of the isotropic and anisotropic 3D graphene networks. Then, the latest research progress of the applications of the 3D graphene networks, including thermal interface materials, phase change materials, electromagnetic interference shielding materials and microwave absorbing materials, is reviewed. Finally, the development and outlook of the 3D graphene networks have prospected. This review can provide new perspectives and research directions for the future development of the 3D graphene networks in heat dissipation and electromagnetic protection for 5G electronic devices.
Microstructure of high thermal conductive mesophase pitch-based carbon fibers
YE Chong, WU Huang, ZHU Shi-peng, FAN Zhen, HUANG Dong, HAN Fei, LIU Jin-shui, YANG Jian-xiao, LIU Hong-bo
 doi: 10.1016/S1872-5805(21)60050-1
Abstract(129) HTML(69) PDF(19)
The microstructural characteristics of the high thermal conductive (500−1127 W·m−1·K−1) mesophase pitch-based carbon fibers were investigated based on the characterization of XRD, Raman spectroscopy, SEM and TEM. The relationship between microstructural characteristics and thermal conductivity was discussed. The results show that the radial structure is always accompanied by a split structure and high thermal conductivity. La has more significant impact on the thermal conductivity than Lc, and ID/IG value on the cross section obtained from Raman spectra can be used as an essential index to evaluate the thermal conductivity of the carbon fibers. The microstructural characteristics including large graphite crystallite size, high preferred orientation degree along the axis direction, and few crystallite defects contribute to the high thermal conductivity of the carbon fibers.
Preparation and characterization of graphitized polyimide film/epoxy resin composites with high thermal conductivities
LI Wen-long, LI Xuan-ke, SHEN Ke, XU Hui-tao, GUO Jian-guang, WU Yong
 doi: 10.1016/S1872-5805(21)60091-4
Abstract(6) HTML(4) PDF(2)
The graphitized polyimide films (GPFs) and the graphitized polyimide tapes (GPTs) were coated with epoxy resins (EP), then their composites were prepared by hot-pressing the laminated GPFs and stacked GPTs, respectively. The crystal structure, morphology and optical texture of GPF and GPT as well as their epoxy adhered composites were characterized by X-ray diffraction, scanning electron microscopy and polarized light microscopy. The effects of volume fraction and dimension of GPF and GPT on the thermal conductivity of their composites were investigated. The thermal conductivity and thermal diffusion coefficient of GPT/EP composites increase with GPT volume fraction. Owing to the gap among GPTs, the thermal conductivity perpendicular to the hot-pressing direction of GPT/EP composite stacked with 80% GPT is changeable from 453 W (m·K)−1 to 615 W (m·K)−1. The GPF/EP composite laminated with 80% GPF, showing a highly oriented sandwich structure, possesses the thermal conductivity of 894 W (m·K)−1. However, the thermal conductivity along the hot-pressing direction of GPT/EP and GPF/EP composites with 80% of GPT and GPF is 1.82 W (m·K)−1 and 1.15 W (m·K)−1 respectively. The obvious differentia in the thermal conductivity at perpendicular and parallel to hot-pressing directions further confirms that the two composites are highly oriented.
One-pot modified “grafting-welding” preparation of graphene/ polyimide composite film for superior thermal management
LI Hao-liang, WU Xian, CHENG Kui, ZHU Mo-han, WANG Liu-si, YU Hong-liu, YANG Jun-he
 doi: 10.1016/S1872-5805(21)60076-8
Abstract(24) HTML(9) PDF(3)
Thermal management has been attracted much more attention due to the rapid development of 5G communication techniques. In this work, we propose an integrated “grafting-welding” method to deliver graphene/polyimide (g-A-mGO/PI) composite films. The modification is firstly conducted by using 1,3-Bis(4-aminophenoxy) benzene (APB-134) to anchor terminal amino groups on GO sheets. Hence, the in-situ polymerization of polyamic acid can directly occur with adding of pyromellitic dianhydride (PMDA) at these reactive sites to connect the micron-sized GO platelets through the chain propagation of polyimide (PI). The optimized g-A-mGO/PI-7% film exhibits a considerable enhancement of in-plane thermal conductivity (κ) by 48.92%. Moreover, it also displays superior anti-bending performance and survives from a 2000-cycle bending with small radius test, delivering an electrical resistance change less than 10%. Such a novel approach enables effective pathway for phonon transportation between graphene sheets to reduce the phonon scattering, and thereby offers a prospective application of the functionalized graphene derivatives for heat dissipation or thermal interface materials.
TiC-modified CNTs as reinforcement fillers of isotropic graphite issued from mesocarbon microbeads
LIN Xiang-bao, CHEN Hui, WU Jing, WU Zhi-gang, LI Run, LIU Hong-bo
 doi: 10.1016/S1872-5805(21)60067-7
Abstract(63) HTML(13) PDF(6)
Multi-walled carbon nanotubes (CNTs) were modified by nano-TiC using a pressureless spark plasma sintering technology. TiC-modified carbon nanotubes (T-CNTs) were added into mesocarbon microbeads (MCMBs) to prepare high performance isostatically pressed graphite materials. The structures of T-CNTs and as prepared isotropic graphite materials were characterized by XRD, SEM, TEM, etc. The mechanical properties and thermal properties of isotropic graphite reinforced by T-CNTs were measured by a micro-controlled electronic universal testing machine, laser thermal conductivity meter and thermal expansion coefficient meter. Results show that nano-TiC is successfully grown on the surface of CNTs. Compared with the isotropic graphite prepared from MCMBs without T-CNTs, the isotropic graphite with T-CNTs has a significant improvement in physical properties (density, open porosity and volume shrinkage). The flexural strength and the degree of graphitization of isotropic graphite with T-CNTs is increased by 70% and 10%, respectively, the thermal properties are also improved to some degree.
“Egg-box”-assisted preparation of hierarchical porous carbon with excellent electrochemical property
LI Shi-jie, ZHANG Ming-yang, GAO Yan, LI Hui, WANG Qian, ZHANG Linhua
 doi: 10.1016/S1872-5805(21)60068-9
Abstract(38) HTML(17) PDF(4)
Based on the "egg-box" structure of calcium alginate in enteromorpha prolifera (EP), the carbonized products of EP are treated by HCl pickling to remove Ca2+ ions from calcium alginate and form the "egg-box" model initial pore structure. Then EP-based activated carbon is prepared by KOH activation method with the treated carbonized products as precursors. The pore characteristics and electrochemical properties of EP-based activated carbon are studied. The existence of hierarchical porous structures in EP-based activated carbon leads to a high specific surface area (SBET) up to 3283 m2 g−1, with more than 66% surface area provided by mesopores. This hierarchical porous carbon shows excellent electrochemical property when used as electrode materials for a supercapacitor, even at high current densities. The gravimetric capacitance value of the EP-based activated carbon reaches up to 361 F g−1 at the current density of 0.1 A g−1, the capacitance even remains at 323 F g−1 at the current density of 10 A g−1, demonstrating excellent high-rate capacitive performance.
Preparation of 3D graphene-carbon nanotubes-magnetic hybrid aerogels for dye adsorption
Zu Rong Ang, Ing Kong, Rachel Shin Yie Lee, Cin Kong, Akesh Babu Kakarla, Ai Bao Chai, Wei Kong
 doi: 10.1016/S1872-5805(21)60029-X
Abstract(232) HTML(114) PDF(29)
Novel hybrid aerogels, which can be magnetically extracted from water to avoid filtration, were prepared by adding ZnCl2, NiCl2·6H2O, FeCl2·4H2O and FeCl3·6H2O into a suspension of graphene oxide and oxidzed carbon nanotubes followed by co-precipatation under basic condition, crosslinking with polyvinyl alcohol in water and freeze-drying. The hybrid aerogels consist of magnetic Ni0.5Zn0.5Fe2O4 nanoparticles, graphene oxide, carbon nanotubes and polyvinyl alcohol, which have active sites that attract dye molecules and can be extracted from water by applying magnetic field. Under an optimal mass ratio of the components, the optimized hybrid aerogel has a high adsorption capacity (qe=71.03 mg g−1 for methylene blue) and a moderate magnetic strength of MS = 3.519 emu g−1. Its removal efficiencies for methylene blue, methyl orange, crystal violet and their mixture with an equal mass are 70.1%, 4.2%, 8.9% and 11.1%, respectively under the same dye concentration of 0.025 mg. mL−1. It can be reused for 3 regeneration cycles with a regeneration efficiency of over 82%. Also it is not toxic to the living organism, suggesting that it is promising as an adsorbent for treating industrial wastewater.
Porous V2O3@C Composite Anodes with Pseudocapacitive Properties for Lithium-ion Capacitors
Ren Xiaolong, Ai Desheng, Lv Ruitao, Kang Feiyu, Huang Zheng-Hong
 doi: 10.1016/S1872-5805(21)60070-7
Abstract(737) HTML(16) PDF(17)
Porous V2O3@C composites were synthesized via a NaCl template-assisted freeze-drying strategy. The kinetic analysis showing the charge storage mechanism in the V2O3@C anode was performed. A lithium ion capacitor device based on this V2O3@C composite anode and a commercial activated carbon cathode was constructed. Results show that the as-constructed device exhibits high energy density, high power density as well as long cycle stability, indicating the great promise of our porous V2O3@C composites for the high-performance Li ion capacitors.
Structure and Electrochemical properties of coconut shell-based hard carbon as anode materials for potassium ion batteries
HUANG Tao, PENG Da-chun, CHEN Zui, XIA Xiao-hong, CHEN Yu-xi, LIU Hong-bo
 doi: 10.1016/S1872-5805(21)60069-0
Abstract(97) HTML(61) PDF(9)
Biomorphic hard carbon recently attracted widely interest as anode materials for potassium ion batteries (PIBs) owing to their high reversible capacity, but high preparation cost and poor cycle stability significantly hinder its practical application. In this study, coconut shell-derived hard carbon (CSHC) was prepared from waste biomass coconut shell using a one-step carbonization method, which was further used as anode materials for potassium ion batteries. The effects of carbonization temperature on the microstructure and electrochemical properties of the CSHC materials were investigated by X-ray diffraction, nitrogen adsorption-desorption isotherms, Raman spectroscopy, scanning electron microscope, transmission electron microscope, and cyclic voltammetry, etc. The results suggested that the coconut shell hard carbon carbonized at 1 000 °C (CSHC-10) possessed suitable graphite microcrystallines size, pore structure and surface defect content, which exhibited the best electrochemical performance. Specifically, CSHC-10 presented a high reversible specific capacity of 254 mAh·g−1 at 30 mA·g−1 with an initial Coulombic efficiency of 75.0%, and the capacity retention was 87.5% after 100 cycles and 75.9% after 400 cycles at 100 mA·g−1. The CSHC with high capacity and good cycling stability demonstrates to be an excellent potassium storage material.
Micro/mesopore carbon spheres derived from sucrose for high performance supercapacitors
SHI Jing, TIAN Xiao-dong, LI Xiao, LIU Ye-qun, SUN Hai-zhen
 doi: 10.1016/S1872-5805(21)60044-6
Abstract(100) HTML(63) PDF(10)
Micro/mesopore carbon spheres as electrode materials of supercapacitors were prepared by hydrothermal carbonization followed by KOH/NaOH activation using sucrose as the carbon precursor. The effects of KOH and NaOH activation parameters on the specific surface area, pore size distribution and electrochemical performance of the carbon spheres were investigated. Results indicate that the use of NaOH leads to the development of mesopores while the use of KOH is favorable to increase specific surface area and micropore volume. The pore size distribution of carbon spheres could be adjusted by varying the fraction of NaOH in the activation agent. A balanced capacitance and rate performance of the supercapacitor electrode in both 6 mol L−1 KOH aqueous electrolyte and 1 mol L−1 MeEt3NBF4/PC electrolyte is achieved when the carbonized product is activated at a mass ratio of NaOH+KOH/ carbonized product of 3∶1 with a NaOH/KOH mass ratio of 2∶1. As-prepared porous carbon delivers a capacitance of 235 F g-1 at 0.1 A g-1 and capacitance retention rate of 81.5% at 20 A g-1 in the 6 mol L−1 KOH aqueous electrolyte. In 1 mol L−1 MeEt3NBF4/PC, the cell based on the porous carbon delivers the highest energy and power output of 30.4 Wh kg−1 and 18.5 kW kg−1, respectively.
Coal-based graphene as a promoter of TiO2 for photocatalytic degradation of organic dyes
LIU Guo-yang, LI Ke-ke, JIA Jia, ZHANG Ya-ting
 doi: 10.1016/S1872-5805(21)60047-1
Abstract(171) HTML(69) PDF(17)
A reduced graphene oxide (H-rGO)/TiO2-composite (H-TiO2@rGO) as a catalyst for photocatalytic degradation of rhodamine B (Rh B) and methyl orange (MO) was prepared by hydrothermal treating a dispersant of TiO2 nanoparticles with sizes of 5-10 nm and GO obtained by the Hummers method from coal-based graphite in water. Compared with the M-TiO2@GO and M-TiO2@rGO composites by a wet mixing method, results indicated that the TiO2 nanoparticles in H-TiO2@rGO were uniformly decorated on both sides of rGO sheet, forming a stacked-sheet structure while apparent aggregation of TiO2 nanoparticles was found in both M-TiO2@GO and M-TiO2@rGO. Therefore, H-rGO@TiO2 had the highest catalytic activity towards degradation of Rh B and MO under visible light irradiation among the three, where the incorporation of rGO into TiO2 helps to narrow the band gap of TiO2, inhibit the recombination rate of electron–hole pairs and provide conductive networks for electron transfer.
Preparation of a N, S, P-codoped and oxidized porous carbon for efficient adsorption of U(VI)
LIU Yan, LIU Xiao-peng, DAI Ying, WANG Yun, YUAN Ding-zhong, LIU Jin-biao, CHEW Jia-wei
 doi: 10.1016/S1872-5805(21)60055-0
Abstract(263) HTML(71) PDF(13)
A N, S, P-codoped and oxidized porous carbon (CS-COOH) was prepared by carbonization of poly(cyclotriphosphazene-co-4,4’-sulfonyldiphenol), followed by KOH activation and oxidation with HNO3. The CS-COOH was used as an adsorbent for U(VI) in aqueous solutions. TEM, SEM, XPS and FTIR were used to characterize the microstructures of CS-COOH before and after adsorption. Results indicate that there is an optimal pH value of 6 for U(VI) adsorption. The adsorption kinetics and isotherm are fitted well by the pseudo-second-order model and the Langmuir model, respectively. The maximum adsorption capacity determined by the Langmuir model at 298 K and a pH value of 6 is 402.9 mg g-1. The CS-COOH has an excellent reusability with a 70% capacity retention of the original value after five adsorption-desorption cycles. The high U(VI) adsorption capacity is mainly attributed to the carboxyl, and P ans S groups by the formation of the UO22+(COO)2 complex, U-O-P and U-O-S bonds.
A wet granulation to dense graphite particles for high volumetric lithium-ion storage
ZHANG Jia-peng, WANG Deng-ke, ZHANG Li-hui, LIU Hai-yan, LIU Zhao-bin, XING Tao, MA Zhao-kun, CHEN Xiao-hong, SONG Huai-he
 doi: 10.1016/S1872-5805(21)60051-3
Abstract(182) HTML(105) PDF(19)
Graphite is the most widely used anode material for lithium ion batteries (LIBs), and increasing the sphericity and density of graphite is the main way to further improve energy density of LIBs. Herein, we report a simple preparation of high tap-density graphite granules by the high-shear wet granulation. In this way, we densified two kinds of graphite into granule, namely wet-granulation graphitic onion-like carbon (WG-GOC) and wet-granulation artificial graphite (WG-AG). It is found that, compared with the original graphite before granulation, the tap density of WG-GOC increases by ca.34%, and WG-AG increases by ca.44%. Therefore, when as the anode of LIBs,, the volumetric capacities of WG-GOC and WG-AG have increased by ca.35% and ca.55%, respectively, at the current density of 50 mA g−1. In addition, the rate performance of WG-GOC also has been significantly improved. The volumetric capacity of WG-GOC increased by 169.1% at the current density of 2000 mA g−1. The significant improvement of electrochemical performance benefits from the higher tap density of the prepared graphite granules. Hence, we developed a facile wet-granulation to prepare high tap-density graphite anodes, which conducive to the development of high volumetric capacity.
Preparation of high-performance anthracite-based graphite anode materials and their lithium storage properties
LI Yuan, TIAN Xiaodong, SONG Yan, YANG Tao, WU Shijie, LIU Zhanjun
 doi: 10.1016/S1872-5805(21)60057-4
Abstract(111) HTML(63) PDF(16)
In this study, cost-effective anthracite and industrial silicon powder were used as precursor and catalyst, respectively, to prepare graphite with various structure, during which the catalytic mechanism was analyzed. The results demonstrate that the as-obtained sample with 5% silicon catalyst (G-2800-5%) exhibits the best overall lithium storage performance. In detail, G-2800-5% display the best graphite structure with graphitization degree of 91.5%. As anode materials, a high reversible capacity of 369.0 mAh g−1 can be achieved at 0.1 A g−1. Meanwhile, the reversible capacity of 209.0 mAh g−1 can be obtained at the current density of 1 A g−1. It also delivers good cyclic stability with a 92.2% retention after 200 cycles at 0.2 A g−1. The highly developed graphite structure, which is favorable to the formation of stable SEI and reduced lithium ion loss should be responsible for the superior electrochemical performance.
Preparation of N/P co-doped waste cotton fabric-based activated carbon for supercapacitor application
HUANG Ling, WANG Shuai, ZHANG Yu, HUANG Xiang-hong, PENG Jun-jun, YANG Feng
 doi: 10.1016/S1872-5805(21)60054-9
Abstract(82) HTML(33) PDF(9)
Transforming waste resources into energy storage materials is a new way to turn waste into treasure and solve the problem of energy shortage and environmental pollution in current society. In this paper, nitrogen/phosphorus co-doped activated carbon material was synthesized from the waste cotton fabric by one-step carbonization and activation in molten salt system combined with ammonium polyphosphate co-doping technology. The morphology, structure and composition of the materials were characterized by scanning electron microscopy (SEM), nitrogen adsorption desorption (BET), Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) were used to test the supercapacitor performance of the prepared materials. The results show that the waste cotton fabric, which is mixed with ammonium polyphosphate in the ZnCl2/KCl molten salt medium, then treated by carbonization and activation under high temperature, generates the nitrogen/phosphorus co-doped activated carbon with the specific surface area of 751 m2·g−1. In the three-electrode system, the specific capacitance is as high as 423 F·g−1 (at a current density of 0.25 A·g−1), and its capacitance retention is as high as 88.9% of the initial capacitance after 5000 cycles at a current density of 5 A·g−1. Meanwhile, when the material was assembled into a symmetrical supercapacitor, the achieved energy density can be up to 28.67 Wh·kg−1 at a power density of 200 W·kg−1. According to these results, converting waste cotton fabric resources into energy storage materials has succeeded in achieving high value-added reuse of waste textiles.
Study on the preparation of MoSi2 modified HfB2-SiC ultra high tem-perature ceramic anti-oxidation coating by liquid phase sintering
REN Xuan-ru, WANG Wei-guang, SUN Ke, HU Yu-wen, XU Lei-hua, FENG Pei-zhong
 doi: 10.1016/S1872-5805(21)60060-4
Abstract(82) HTML(52) PDF(16)
In this paper, a liquid-phase sintering method was developed by combining in-situ reaction method with slurry method to prepare HfB2-MoSi2-SiC coatings with controllable composition, content and thickness. The effect of MoSi2 content on the oxidation protection behavior of HfB2-MoSi2-SiC composite coating under dynamic aerobic environment at room temperature ~ 1500 ℃ and static constant temperature air at 1500 ℃ was studied, the relative oxygen permeability was used to characterize the oxidation resistance of the coating. The results of dynamic oxidation test at room temperature ~ 1500 ℃ showed that the initial oxidation weight loss of the samples was delayed from 775 ℃ to 821 ℃, and the maximum weight loss rate decreased from 0.9×10−3 mg·cm−2·s−1 to 0.2×10−3 mg·cm−2·s−1 with the increase of MoSi2 content, the lowest relative oxygen permeability was reduced to 12.2%, resulting in the weight loss of the sample from 1.8% to 0.21%. In this paper, the mechanism of MoSi2 enhancing the ability of oxidation protection of the coating is revealed. With the increase of MoSi2 content, the amount of SiO2 glass phase in the coating is increased, and the dispersion of Hf-oxide on the coating surface is promoted, thus, the Hf-Si-O compound glass layer with higher stability can be formed, and the weight loss rate of the sample reduced from 0.46% to 0.08% after 200 h oxidation at 1500 ℃ in constant temperature air.
Hierarchical Porous Carbon from lignin-rich residue for High-Performance Supercapacitor
FANG Yan-yan, ZHANG Qian-yu, ZHANG Dong-dong, CUI Li-feng
 doi: 10.1016/S1872-5805(21)60058-6
Abstract(131) HTML(36) PDF(6)
Designing electrically conductive electrode material with a hierarchical pore structure from abundant raw material remains a significant challenge in the development of energy storage research. In this work, 3D porous carbons with high surface areas are synthesized via high-temperature carbonization and activation. The synthesized activated carbons deliver a specifical capacitance of 280 F g−1 and area-specific capacitance of 1.3 F cm−2 at a current density of 0.5 A g−1. The assembled symmetric supercapacitor can deliver a high energy output (7.7 Wh kg−1 at 5200 W kg−1). Thus, it is demonstrated the repurposing of lignin waste as electrode material can be a feasible resource that goes beyond the limitations of utilizing lignin in low value-added applications.
A correlation of the hydrogen evolution reaction activity to the defects formed by the decomposition of doped phosphorus species in carbon nanotubes
AI Jie, LIU Zi-wu, SUN Mao-mao, LIU Ling, WANG Quan-de
 doi: 10.1016/S1872-5805(21)60052-5
Abstract(106) HTML(61) PDF(10)
The phosphorus-doped carbon materials as one of novel carbon catalysts towards the hydrogen evolution reaction (HER) have attracted considerable attention over the past years. However, the role of C-P species palyed in the HER activity is still not clear up to now. Phosphorus-doped carbon nanotubes (P-CNTs) were prepared by chemical vapor deposition and annealed at 900, 1000 and 1200 ℃ to remove all or parts of phosporus species, resulting in four samples with different proportions of graphite-, pyridine- and pyrrole-like P species. The correlations between their HER activity and the contents of three types of P species were investigated. Results showed that the content of graphite-like P decreased with the annealing temperature and no graphite-like P was retained at 1200℃. The HER activity increased with the annealing temperature and the one annealed at 1200 ℃ had the highest HER activity in an acid medium with an overpotential of 0.266 V at a current density of 10 mA/cm−2. Density functional theory calculations revealed that the pentagon- and nine-membered ring defects formed by the destruction of graphite-P species contributed mainly to the HER activity, which gave a deep insight into the active sites for HER.
KOH Treated Mesocarbon Microbeads as High Rate Anode for Potassium-Ion Batteries
XIAO Nan, GUO Hong-da, XIAO Jian, WEI Yi-bo, MA Xiao-qing, ZHANG Xiao-yu, QIU Jie-shan
 doi: 10.1016/S1872-5805(21)60059-8
Abstract(78) HTML(27) PDF(5)
Graphite is one of the most promising anode materials for potassium-ion batteries (PIBs) due to its low cost and stable discharge plateau. However, its poor rate performance still needs to be improved. Herein, a novel graphitic anode was designed from commercial mesocarbon microbeads (MCMB) by KOH treatment. Through limited oxidation and slight intercalation, an expanded layer with enlarged interlayer spacing formed on the surface of MCMB, by which the K+ diffusion rate was significantly improved. When served as the PIB anode, this modified MCMB delivered a high plateau capacity below 0.25 V (271 mAh g−1), superior rate capability (160 mAh g−1 at 1.0 A g−1), excellent cycling stability (about 184 mAh g−1 after 100 cycles at 0.1 A g−1), and high initial coulombic efficiency with carboxymethyl cellulose as binder (79.2%). This work provides a facile strategy to prepare graphitic materials with superior potassium storage property.
Effect of surface functionalization on the surface and interfacial properties of thermoplastic-coated carbon fibers
SU Ya-nan, ZHANG Shou-chun, ZHANG Xing-hua, JING De-qi
 doi: 10.1016/S1872-5805(21)60023-25
Abstract(89) HTML(35) PDF(12)
Hydroxyl- and amino- functionalized carbon fibers (CF-OH and CF-NH2) were prepared by surface oxidation with mixed acid and grafting with ethylenediamine, respectively. The functionalized CFs were sized with a sulfonated poly (ether ether ketone) (SPEEK) sizing agent to prepare CF-OH-SPEEK and CF-NH2-SPEEK. The effect of surface functionalization on the surface properties of CFs and the interfacial properties in PEEK maxtrix composites were investigated. Results show that the contents of polar functional groups and wettability of CFs increase significantly after surface functionalization. There are chemical reactions between CFs and the sizing agent, which improve the interfacial adhesion between CFs and the sizing agent. The interfacial shear strengths of CF-OH-SPEEK and CF-NH2-SPEEK reinforced PEEK matrix composites are increased by 6.2% and 14.0%, respectively, as compared with that of desized-SPEEK CFs. The surface functionalization is beneficial to improve the interfacial adhesion of thermoplastic-coated CF/PEEK composites.
A sustainable strategy to prepare porous carbons with tailored pores from shrimp shell for use as the supercapacitor electrode materials
Gao Feng, Xie Ya-qiao, Zang Yun-hao, ZHOU Gang, QU Jiang-ying, WU Ming-bo
 doi: 10.1016/S1872-5805(21)60019-7
Abstract(50) HTML(26) PDF(3)
Highly efficient synthesis of nitrogen-doped carbons with different porous structures is reported using shrimp shell as the carbon and nitrogen source, and its CaCO3 component as the hard template and the activator. The content of CaCO3 in shrimp shell can be tuned easily in the range of 0-100% by leaching with an acetic acid solution for different times. CaO derived from decomposition of CaCO3 acts as the activator and template to tailor the pore sizes of the carbons. CO2 derived from decomposition of CaCO3 also plays an activating role. Their specific surface areas, pore volumes, ratios of micropore volumes to total pore volumes can be adjusted in the range of 117.6-1137 m2 g-1, 0.14-0.64 cm3 g-1, and 0-73.4%, respectively. When used as the electrodes of supercapacitor, the porous carbon obtained with a leaching time of 92 min exhibits the highest capacitances of 328 F g-1 at 0.05 A g-1 in a 6 M KOH electrolyte and 619.2 F g-1 at 0.05 A g-1 in a 1 M H2SO4 electrolyte. Its corresponding energy density at a power density of 1470.9 W kg-1 is 26.0 Wh kg-1. This work provides a low cost method for fabricating porous carbons to fulfill the high-value-added use of biomass.
Display Method:
2021, (4): 1-1.  
Abstract(132) HTML(19) PDF(40)
2021, 36(4): 1-5.  
Abstract(52) HTML(12) PDF(18)
Phosphorescent carbon dots: Microstructure design, synthesis and applications
KANG Hai-xin, ZHENG Jing-xia, LIU Xu-guang, YANG Yong-zhen
2021, 36(4): 649-664.   doi: 10.1016/S1872-5805(21)60083-5
Abstract(210) HTML(64) PDF(70)
Phosphorescent carbon dots (CDs) have great potential in energy, information, biomedicine, and other fields because of their long lifetime, long wavelength emission, and low background interference. However, there are still some challenges in their preparation and understanding their luminescence mechanism. For example, their triplet states are easily affected by the external environment, which leads to phosphorescence quenching. The phosphorescence mechanism and the effects of element doping, rigidity of structure, and conjugated structure on their properties are reviewed to address these issues. The synthesis methods include one step and two step methods. The uses of phosphorescent CDs are summarized and include information security, light emitting diodes, ion detection, and biological imaging. The existing problems are discussed and development directions are proposed.
Recent advances in carbon-supported iron group electrocatalysts for the oxygen reduction reaction
LI Ping, WANG Huan-lei
2021, 36(4): 665-682.   doi: 10.1016/S1872-5805(21)60072-0
Abstract(136) HTML(62) PDF(37)
Metal-air batteries are emerging energy devices that have received worldwide attention. The oxygen reduction reaction (ORR) is the key electrochemical process of metal-air batteries. The sluggish nature of ORR kinetics and the high cost of Pt-based ORR catalysts have severely hindered their large-scale application. As earth-abundant elements, the iron group elements have a variety of hybrid orbitals, and their incorporation into the carbon skeleton achieves good ORR catalytic activity, giving them great potential for substituting for Pt-based catalysts. Here, their uses for ORR and the function of each active site in the ORR process are summarized. The relationship between the microstructure and performance of these catalysts may help us fully understand the role of iron group elements in ORR and provide basic insight into the design of cheap catalysts with outstanding ORR catalytic performance in the future.
Carbon materials for solar-powered seawater desalination
WANG Tian-yi, HUANG Heng-bo, LI Hao-liang, SUN You-kun, XUE Yu-hua, XIAO Shu-ning, YANG Jun-he
2021, 36(4): 683-701.   doi: 10.1016/S1872-5805(21)60066-5
Abstract(311) HTML(127) PDF(69)
Carbon materials are widely used in solar-powered seawater desalination (SSD) and have attracted a lot of attention in recent years. Recent developments of carbon-based solar absorbers in SSD are reviewed, including composites of carbon materials with other materials such as metal nanoparticles, semiconductors and biomass materials, their photothermal conversion mechanisms, light utilization efficiencies and salt resistance, and the processes of thermal transport and water transfer. The important roles of carbon in SSD are highlighted, including increasing light absorption, improving photothermal conversion efficiency, and balancing water transfer and salt resistance. The key challenges of carbon-based materials in SSD applications are discussed.
Charge storage mechanisms of manganese dioxide-based supercapacitors: A review
TANG Xiao-ning, ZHU Shao-kuan, NING Jian, YANG Xing-fu, HU Min-yi, SHAO Jiao-jing
2021, 36(4): 702-710.   doi: 10.1016/S1872-5805(21)60082-3
Abstract(137) HTML(80) PDF(39)
Carbon-based materials, such as carbon nanotubes, graphene and mesoporous carbons, are typical electrochemical double-layer capacitive electrodes of supercapacitors (SCs). Although these carbon electrode materials have excellent electrochemical stability, they usually have a low capacitance. Therefore, pseudocapacitive materials are often combined with them to increase capacitance. Among these pseudocapacitive materials, manganese dioxide (MnO2) has been widely used because of its high theoretical specific capacitance, low-cost, abundance, and environmentally friendly nature. However, the use of MnO2 often produces rather low actual specific capacitances due to its poor electrical conductivity, phase transformation and large volumetric changes during repeated charge and discharge. To explore high-performance MnO2/carbon composite electrode materials, it is necessary to understand the charge storage mechanisms of MnO2. These are analyzed and classified into four types: surface chemisorption of cations, intercalation-deintercalation of cations, a tunnel storage mechanism and a charge compensation mechanism. Although the fourth involves pre-interaction of the cations in MnO2, the essence of all these mechanisms is the valence transition of manganese atoms between +3 and +4, and many mechanisms are usually involved in MnO2-based SCs because of the complicated charge storage process. Critical challenges and possible strategies for achieving high-performance MnO2/carbon-based SCs are discussed and prospective solutions are presented.
Research progress on graphene-based materials for high-performance lithium-metal batteries
WANG Xin, HUANG Run-qing, NIU Shu-zhang, XU Lei, ZHANG Qi-cheng, Abbas Amini, CHENG Chun
2021, 36(4): 711-728.   doi: 10.1016/S1872-5805(21)60081-1
Abstract(257) HTML(122) PDF(75)
Due to their relatively low energy density, commercial lithium-ion batteries (LIBs) have faced difficulty in meeting the increasing requirements of energy storage devices for portable electronics and electric vehicles. Lithium (Li) with a high theoretical specific capacity (3860 mAh g−1) and low density (0.59 g cm−3) is regarded as one of the best anodes for next-generation high energy density Li metal batteries, e.g., Li-S and Li-O2 batteries. However, the safety problems induced by uncontrollable Li dendrite growth and a low Coulombic efficiency caused by an unstable solid electrolyte interphase layer, have limited their practical application. Graphene-based materials (GBMs) with a high specific surface area and controllable structures and chemical properties, have been shown to be important in solving these problems. Various protection strategies for Li metal anodes using GBMs are summarized and the design of GBMs with different roles and functions in Li metal protection is discussed. Challenges and possible solutions for the future development of GBMs used in Li metal anodes are discussed.
Research progress on the effect of graphene oxide on the properties of cement-based composites
WANG Qin, QI Guo-dong, WANG Yue, ZHENG Hai-yu, SHAN Si-han, LU Chun-xiang
2021, 36(4): 729-750.   doi: 10.1016/S1872-5805(21)60071-9
Abstract(155) HTML(42) PDF(28)
Graphene oxide (GO) has significant strengthening and toughening effects on cement-based composites as a nano-reinforcement filler, and research progress on these materials is presented. The effects of GO on the properties of cementitious composites are summarized, including the dispersion stability of GO in a cement environment, the hydration properties, workability, rheological properties, mechanical properties and durability. Reinforcement and toughening mechanisms are proposed. Prospective research trends are discussed based on the problems already encountered
Non-layered transition metal carbides for energy storage and conversion
GAO Yin-hong, NAN Xu, YANG Yao, SUN Bing, XU Wen-li, Wandji Djouonkep Lesly Dasilva, LI Xuan-ke, LI Yan-jun, ZHANG Qin
2021, 36(4): 751-778.   doi: 10.1016/S1872-5805(21)60065-3
Abstract(256) HTML(113) PDF(33)
Non-layered transition metal carbides (NL-TMCs) have diverse morphologies and structures, and tunable stoichiometric ratios, giving them many intriguing electrical/catalytic properties such as high gravimetric capacities, high conductivity and excellent stability. The latest progress in the use of NL-TMCs for energy conversion and storage applications is reviewed. Several routes to synthesize NL-TMCs are described, including carbothermal reduction, chemical vapor deposition, a template-assisted method and a hydro/solvothermal method. Their electrochemical performance in lithium-ion batteries, lithium-sulfur batteries and catalytic water splitting are presented. Current challenges for the rational design and fabrication of NL-TMCs for practical applications are discussed and future research suggestions are made.
Research progress on the biomedical uses of graphene and its derivatives
LIU Yang, DING Jing, WANG Qi-qi, WEN Mei-ling, TANG Ting-ting, LIU Yong, YUAN Rong, LI Yong-feng, AN Mei-wen
2021, 36(4): 779-793.   doi: 10.1016/S1872-5805(21)60073-2
Abstract(109) HTML(82) PDF(24)
Graphene (Gr) is a monolayer of carbon atoms in a two-dimensional honeycomb lattice, and has derivatives of graphene oxide and reduced graphene oxide. Gr is widely used in various fields for its good optics, conductivity, mechanical properties, low toxicity, antibacterial properties, biocompatibility and stability. Graphene oxide and reduced graphene oxide have similar properties to Gr, and all three materials have advantages and disadvantages and are often not used alone but are composited with other materials to improve their properties for a particular application. From the perspectives of the toxicity and antibacterial properties of Gr and its derivatives, this paper reviews their uses in treating skin wounds and tumours, promoting the regeneration of skeletal muscle and bone, and facilitating drug loading and diagnosis. The problems associated with these applications are analyzed and solutions are suggested. Future research and development prospects for Gr-based materials are presented.
Synthesis and use of hollow carbon spheres for electric double-layer capacitors
XU Kuang-liang, LIU Jing, YAN Zhao-xiong, JIN Mei, XU Zhi-hua
2021, 36(4): 794-809.   doi: 10.1016/S1872-5805(20)60517-0
Abstract(216) HTML(107) PDF(25)
Supercapacitors have become an important energy storage device. Based on their energy storage mechanism, supercapacitors are generally categorized into pseudocapacitors and electric double-layer capacitors (EDLCs). Nowadays, carbon materials are used as the electrodes in commercial EDLCs. Hollow carbon spheres (HCSs) have attracted extensive attention for use as the electrode materials of EDLCs because of their large specific surface area, high electrical conductivity, excellent electrochemical stability and high mechanical strength. Progress on the preparation of HCSs is reviewed, including the hard and soft templating methods, template-free methods and the modified Stöber method. Their electrochemical performance as the electrode materials of EDLCs and the effect of their specific surface area, pore size and doped foreign atoms on their electrochemical performance are summarized, which gives insight into their low-cost preparation and high-performance for use in supercapacitors.
Research articles
Ultra-thin 2D MoO2 nanosheets coupled with CNTs as efficient separator coating materials to promote the catalytic conversion of lithium polysulfides in advanced lithium-sulfur batteries
KONG Zhen-kai, CHEN Yang, HUA Jing-zhao, ZHANG Yong-zheng, ZHAN Liang, WANG Yan-li
2021, 36(4): 810-820.   doi: 10.1016/S1872-5805(21)60080-X
Abstract(137) HTML(62) PDF(26)
A severe shuttle effect and the slow kinetics of lithium polysulfide (LiPS) conversion are two major obstacles to the practical use of lithium sulfur batteries. Ultra-thin 2D MoO2 nanosheets (MoO2 NSs) have been synthesized by chemical vapor deposition and then mixed with carbon nanotubes (CNTs) for use as coating materials of the Celgard 2400 polypropylene separator to solve these problems. The 2D character of MoO2 NSs produced high surface/volume ratios and abundant active binding sites for anchoring LiPSs. In addition, the partial reduction of MoO2 NSs in a H2/Ar mixture introduced oxygen vacancies in their surface, which acted as catalytic sites for LiPS conversion, while the CNT network ensured rapid electron transfer for LiPS conversion reactions. Symmetric dummy cell tests showed that a 30wt%MoO2/CNT coated separator reduced the energy barrier for Li2S nucleation, and first-principles calculations verified its strong binding energy to entrap LiPSs and increase Li2S precipitation. Because of these features, a cell with a 30wt%MoO2/CNT coated separator had an improved specific capacity of 738 mAh·g−1 at 1 C with a slow decay rate of 0.053% for 800 cycles.
Magnetic modification of used tea leaves for uranium adsorption
YANG Ai-li, YANG Sheng-ya, ZHU Yu-kuan
2021, 36(4): 821-826.   doi: 10.1016/S1872-5805(21)60053-7
Abstract(129) HTML(73) PDF(32)
Used tea leaves, or tea waste (TW), were crushed into powder and mixed with graphene oxide (GO) in water, followed by adjusting the pH value of the resulting suspension with ammonia to 11, adding FeCl2·4H2O under magnetic stirring, filtration and drying to prepare a rGO/Fe3O4/TW (with mass ratios of 1∶2∶1) hybrid material. The structure and crystalline phases of the material were characterized by FTIR and XRD. Isotherms for uranium adsorption were obtained and its kinetics were measured in a conical bottle that was placed in a shaker. The effects of the pH value of the uranium solution, adsorption time and initial concentration on the uranium adsorption were investigated. Results indicate that the hybrid has a much faster adsorption rate than TW with an uranium removal rate up to nearly 100% in 20 min for an initial uranium concentration of 10 mg L−1. The maximum adsorption capacity of the hybrid is 103.84 mg g−1 while that of TW is 97.70 mg g−1. The hybrid with adsorbed uranium can be easily separated from the solution by applying a magnetic field. The isotherms and kinetics of uranium adsorption on the hybrid are best fitted by the Langmuir isotherm model and the pseudo-second-order model, respectively. The hybrid has good reusability with an uranium removal rate of about 85% after 5 cycles.
Regulating the radial structure of polyacrylonitrile fibers during pre-oxidation and its effect on the mechanical properties of the resulting carbon fibers
WANG Yun-feng, WANG Yi-wei, XU Liang-hua, WANG Yu
2021, 36(4): 827-834.   doi: 10.1016/S1872-5805(20)60516-9
Abstract(167) HTML(93) PDF(15)
The radial structure of polyacrylonitrile fibers oxidized before carbonization and its distribution directly affect the performance of the resulting carbon fibers. Optimizing the radial distribution of the oxidized structure and establishing a relationship between this structure and the mechanical properties of the final carbon fibers will help optimize the oxidation conditions for the preparation of high-performance carbon fibers. Solid-state nuclear magnetic resonance spectroscopy, optical microscopy, thermogravimetric analysis, and mechanical tests were used to investigate the effect of the oxidation reaction rate on the radial distribution of the structure of the oxidized fibers and the mechanical properties of the resulting carbon fibers. The oxidation reaction rates were controlled by regulating the oxidation temperature gradient. Results show that the degree of oxidation increases with both the average and initial oxidation rates. By increasing the average oxidation reaction rate, the oxidized structure penetrates deeper into the core region of the fibers, the content of oxygen-containing functional groups increases, the thermal stability of the fibers decreases, and the degree of graphitization of the final carbon fibers increases, but the density of the fibers is decreased and their mechanical properties are degraded. Compared with sample obtained with the lower initial oxidation rate, the number of oxygen-containing functional groups, thermal stability, degree of graphitization and density of the final carbon fibers of the sample with the higher initial oxidation rate are higher, and its tensile strength and modulus are respectively 4.2% and 2.2% higher. A new type of carbon fiber with high strength, medium modulus and a relatively large diameter is obtained under the optimized oxidation conditions.
Conversion of carbon nanotubes into curved graphene with improved capacitance
LI Xiao-yan, WANG Qiang, WANG Huan-wen
2021, 36(4): 835-842.   doi: 10.1016/S1872-5805(21)60086-0
Abstract(108) HTML(42) PDF(35)
Multi-wall carbon nanotubes (MWCNTs) have achieved mass production, but their lengths are in the millimeter range, which is unfavorable for the diffusion of electrolyte ions into their innermost tube. We report an oxidation method to simultaneously cut and unzip MWCNTs along transverse and longitudinal directions, which leads to the formation of curved graphene sheets (CGSs). SEM shows that the curved morphology was retained but the diameters were large after unzipping. This could be caused by the interaction of oxygen-containing functional groups between layers on the edges of the CGSs. Because of the larger number of active sites the specific capacitance is improved. To further increase the capacitive performance, a sample was put into a 0.1 mol L−1 KMnO4 to incorporate MnO2. The microstructure of the resulting CGS-MnO2 hybrid was revealed by electron microscopy, Raman spectroscopy and powder X-ray diffraction. The results indicate that amorphous MnO2 successfully grew on the surface of the CGSs. The capacitive behavior was measured by cyclic voltammetry in a 1 mol L−1 Na2SO4 solution. The CGS-MnO2 had a specific capacitance of 236 F g−1 at 2 mV s−1 (even 127 F g−1 at 100 mV s−1), which is superior to that of MWCNTs (15 F g−1), CGS (88 F g−1) and MWCNT-MnO2 (111 F g−1). In addition, excellent cycling performance was achieved for the CGS-MnO2 hybrid electrode with a 97% capacitance retention over 1000 cycles.
Adsorption and decolorization of hydrogenated coal tar on resin-based activated carbon spheres
WU Jun-cheng, WANG Jian-long, GUAN Tao-tao, ZHANG Guoli, LI Kai-xi
2021, 36(4): 843-850.   doi: 10.1016/S1872-5805(21)60056-2
Abstract(129) HTML(52) PDF(32)
Resin-based activated carbon spheres (ACSs) were prepared by a combined suspension polymerization, carbonization and activation method. The ACSs were then oxidized with nitric acid (NACSs) to modify the surface properties to increase the decolorization of hydrogenated coal tar. The morphology, pore structure, elemental composition and pyrolysis kinetics of the polymer sample were characterized by SEM, N2 adsorption, FTIR, XPS and TGA. Results showed that this oxidation modification of the ACSs has little influence on their surface morphology and pore structure while the numbers of surface oxygen functional groups were remarkably increased. P-benzoquinone (DBD) and N,N-di-sec-butyl-1,4-phenylenediamine (PBQ) were selected as model color compounds for decolorization tests with ACSs and NACSs. The effects of adsorption time, temperature and amount of adsorbent on the decolorization performance were investigated. Under the same adsorption conditions, the amounts of decolorization of DBD and PBQ were 94.5% and 96.6%, respectively for NACSs while those for ACSs were much lower, indicating the outstanding adsorption performance of NACSs. Hydrogen bonds formed between surface functional groups and colored compounds may play a key role in improving the adsorption performance. Moreover, the decolorization of NACSs was still more than 90% after NACSs were recycled 6 times. The decolorization effect of NACSs for real hydrogenated coal tar was also significant and its color faded after adsorption by NACSs, confirming their feasibility for practical use.
Research progress on electrode materials and electrolytes for supercapacitors
JIAO Chen, ZHANG Wei-ke, SU Fang-yuan, YANG Hong-yan, LIU Rui-xiang, CHEN Cheng-meng
2017, 32(2): 106-115.  
Abstract(507) PDF(3157)
Influence of graphene oxide additions on the microstructure and mechanical strength of cement
WANG Qin, WANG Jian, LU Chun-xiang, LIU Bo-wei, ZHANG Kun, LI Chong-zhi
2015, 30(4): 349-356.   doi: 10.1016/S1872-5805(15)60194-9
Abstract(605) PDF(420)
研究了不同掺量下氧化石墨烯(GO)对水泥石以及胶砂微观结构和力学性能的影响。含16.5%水的水泥浆、0.05%GO及3倍于水泥的沙子共混物作为添加剂制备成砂浆。通过SEM、液氮吸附仪和一系列标准实验分别对水泥石的微观形态、孔隙结构、抗压抗折强度以及水泥净浆的流动度、黏度、凝结时间进行表征;考察不同GO掺量下水泥水化放热的变化情况。结果表明:GO对水泥浆有显著增稠和促凝作用;GO的掺入可以有效降低水泥的水化放热量;GO对水泥石有显著的增强增韧效果,28天龄期时,GO质量分数为0.05%的水泥石,3、7和28 d抗压强度和抗折强度同比对照组分别增加52.4%、46.5%、40.4%和86.1%、68.5%、90.5%,胶砂的抗压强度和抗折强度同比对照组分别增加43.2%、33%、24.4%和69.4%、106.4%、70.5%;GO在水泥硬化过程中对水泥石中晶体产物的产生有促进作用并能规整晶体的排布而形成针状晶体簇,改善水泥石中的孔结构,降低水泥石中微孔的体积,增加水泥石的密实度,对水泥石有显著地增强增韧效果。
Advances in the ablation resistance of C/C composites
FU Qian-gang, ZHANG Jia-ping, LI He-jun
2015, 30(2): 97-105.  
Abstract(850) PDF(1261)
C/C复合材料因优异的高温性能被认为是高温结构件的理想材料。然而,C/C复合材料在高温高速粒子冲刷环境下的氧化烧蚀问题严重制约其应用。因此,如何提高C/C复合材料的抗烧蚀性能显得尤为重要。笔者综述C/C复合材料抗烧蚀的研究现状。目前,提高C/C复合材料抗烧蚀性能的途径主要集中于优化炭纤维预制体结构、控制热解炭织构、基体中陶瓷掺杂改性和表面涂覆抗烧蚀涂层等4种方法。主要介绍以上4种方法的研究现状,重点介绍基体改性和抗烧蚀涂层的最新研究进展。其中,涂层和基体改性是提高C/C复合材料抗烧蚀性能的两种有效方法。未来C/C 复合材料抗烧蚀研究的潜在方向主要集中于降低制造成本、控制热解炭织构、优化掺杂的陶瓷相以及将基体改性和涂层技术相结合。
Preparation and properties of reduced graphene oxide/polyimide composites produced by in-situ polymerization and solution blending methods
MA Lang, WANG Guo-jian, DAI Jin-feng
2016, 31(2): 129-134.  
Abstract(630) PDF(1336)
利用化学氧化还原法制备出石墨烯。通过原位聚合法及溶液混合法制备出石墨烯/聚酰亚胺复合材料,考察不同复合材料制备方法对其机械性能及导电性能的影响,并对其作用机理进行探讨。结果表明,制备的石墨烯为二维的单层或寡层材料,加入到聚酰亚胺中能够增强其机械性能及电导率。相比溶液混合法,采用原位聚合法时石墨烯在聚酰亚胺基体中分散更均匀,对其团聚作用有更好的抑制作用,制备的复合材料性能更优异。采用该法加入石墨烯的量为1.0 wt%时,拉伸强度达到了132.5 MPa,提高了68.8%;加入量增加到3.0 wt%时,电导率达6.87×10-4S·m-1,提高了8个数量级,对聚酰亚胺的性能有显著的增强作用。
A review of carbon-carbon composites for engineering applications
SU Jun-ming, ZHOU Shao-jian, LI Rui-zhen, XIAO Zhi-chao, CUI Hong
2015, 30(2): 106-114.  
Abstract(778) PDF(1159)
评价了中国40多年来在航天、航空、光伏、粉末冶金、工业高温炉领域成功应用的针刺C/C,正交3D C/C、径编C/C、穿刺C/C、轴编C/C等五类C/C复合材料的物理、力学、热学、烧蚀、摩擦磨损、使用寿命等性能及特点,并与其他国家相应材料性能进行分析对比,为建立工程应用C/C复合材料共享的数据库平台奠定基础。揭示了炭纤维预制体、炭基体类型、界面结合状态与材料性能的关联度。指出炭纤维预制体结构单元精细化研究和其结构的梯度设计,以及炭基体的优化组合匹配技术,仍是C/C复合材料性能稳定化提升的重点研究方向。
Hydrothermal synthesis of porous phosphorus-doped carbon nanotubes and their use in the oxygen reduction reaction and lithium-sulfur batteries
GUO Meng-qing, HUANG Jia-qi, KONG Xiang-yi, PENG Hong-jie, SHUI Han, QIAN Fang-yuan, ZHU Lin, ZHU Wan-cheng, ZHANG Qiang
2016, 31(3): 352-362.  
Abstract(486) PDF(669)
碳纳米管优异的物理性质和可调的化学组成使其拥有广泛的应用前景。采用低温过程在碳骨架中引入磷原子预期带来可调的化学特性。本研究采用170℃下水热处理碳纳米管-磷酸混合物获得磷掺杂的碳纳米管。磷掺杂的碳管的磷含量为1.66%,比表面积为132 m2/g,热失重峰在纯氧环境下提升至694℃。当掺磷碳纳米管用于氧还原反应时,其起始电位为-0.20 V,电子转移数为2.60,反应电流显著高于无掺杂的碳纳米管。当其用作锂硫电池正极导电材料时,电极的起始容量为1106 mAh/g,电流密度从0.1 C提升至1 C时容量保留率为80%,100次循环的衰减率为每圈0.25%。
Rheological behavior of fresh cement pastes with a graphene oxide additive
WANG Qin, WANG Jian, LU Chun-xiang, CUI Xin-you, LI Shi-yu, WANG Xi
2016, 31(6): 574-584.   doi: 10.1016/S1872-5805(16)60033-1
Abstract(487) PDF(683)
Research progress and potential applications for graphene/polymer composites
ZENG You, WANG Han, CHENG Hui-ming
2016, 31(6): 555-567.  
Abstract(521) PDF(1560)
Adsorption of low-concentration methylene blue onto a palygorskite/carbon composite
WU Xue-ping, XU Yan-qing, ZHANG Xian-long, WU Yu-cheng, GAO Peng
2015, 30(1): 71-78.   doi: 10.1016/S1872-5805(15)60176-7
Abstract(695) PDF(1063)
A graphene/carbon black hybrid material: a novel binary conductive additive for lithium-ion batteries
LI Yong, LU Xiao-hui, SU Fang-yuan, HE Yan-bing, LI Bao-hua, YANG Quan-hong, KANG Fei-yu
2015, 30(2): 128-132.  
Abstract(685) PDF(1562)
采用CTAB为表面活性剂将氧化石墨烯和炭黑均匀分散,经水热过程将二者组装到一起,进而高温热处理得到石墨烯/炭黑杂化材料。该材料是一种具有独特结构和良好性能的石墨烯/炭黑杂化材料作为锂离子电池二元导电剂。炭黑颗粒均匀分布在石墨烯表面,可防止石墨烯片层团聚并进一步提高电子导电效率。由于炭黑可增加对电解液的吸附,促进电极内部锂离子的传输过程,最终提高锂离子电池的倍率性能。结果表明,使用质量分数5% 900 ℃热处理之后的二元导电剂的LiFePO4,在10 C时比容量为73 mAh/g,优于使用10%炭黑导电剂时的LiFePO4 (10 C比容量为62 mAh/g)。按照整个电极质量计算,前者的比容量性能比后者提高了近25%,同时在循环性能方面,前者的稳定性也优于后者。
Recent progress in the preparation of ordered mesoporous carbons using a self-assembled soft template
HUANG Zheng-hong
2012, 27(05): 321-336.  
Abstract(1754) PDF(10)
The preparation of self-assembled ordered mesoporous carbons (SA-OMCs) using a soft template method has many advantages, such as low cost, ease of preparation and control. This paper review the development periods, the basic principles and preparation procedures with an emphasis on the control of morphology and multi-level pore structure of OMCs based on SA-OMCs. And suggest that further research in this area can be focused on expanding the scope of the precursor, improving the flexibility and conductivity of the shaped products, such as fibers and membranes.
Preparation of graphene by chemical vapor deposition
REN Wen-cai, GAO Li-bo, MA Lai-peng, CHENG Hui-ming
2011, 26(01): 71-80.  
Abstract(2234) PDF(40)
Chemical vapor deposition (CVD) is an effective way for the preparation of graphene with large area and high quality. In this review, the mechanism and characteristics of the four main preparation methods of graphene are briefly introduced, including micromechanical cleavage, chemical exfoliation, SiC epitaxial growth and CVD. The recent advances in the CVD growth of graphene and the related transfer techniques in terms of structure control, quality improvement and large area graphene synthesis were discussed. Other possible methods for the CVD growth of graphene were analyzed including the synthesis and nondestructive transfer of large area single crystalline graphene, graphene nanoribbons and graphene macrostructures.