Showing papers by "China Academy of Engineering Physics published in 2016"
TL;DR: A hollow graphene/conducting polymer composite fiber is created with high mechanical and electronic properties and used to fabricate novel fiber-shaped supercapacitors that display high energy densities and long life stability.
Abstract: A hollow graphene/conducting polymer composite fiber is created with high mechanical and electronic properties and used to fabricate novel fiber-shaped supercapacitors that display high energy densities and long life stability. The fiber supercapacitors can be woven into flexible powering textiles that are particularly promising for portable and wearable electronic devices.
620 citations
TL;DR: In this paper, a SiO2 hollow nanosphere-based composite solid electrolyte (SiSE) for Li metal batteries is reported, which is fabricated via in situ polymerizing the tripropylene gycol diacrylate (TPGDA) monomer in the presence of liquid electrolyte.
Abstract: The low Coulombic efficiency and serious security issues of lithium (Li) metal anode caused by uncontrollable Li dendrite growth have permanently prevented its practical application. A novel SiO2 hollow nanosphere-based composite solid electrolyte (SiSE) for Li metal batteries is reported. This hierarchical electrolyte is fabricated via in situ polymerizing the tripropylene gycol diacrylate (TPGDA) monomer in the presence of liquid electrolyte, which is absorbed in a SiO2 hollow nanosphere layer. The polymerized TPGDA framework keeps the prepared SiSE in a quasi-solid state without safety risks caused by electrolyte leakage, meanwhile the SiO2 layer not only acts as a mechanics-strong separator but also provides the SiSE with high room-temperature ionic conductivity (1.74 × 10−3 S cm−1) due to the high pore volume (1.49 cm3 g−1) and large liquid electrolyte uptake of SiO2 hollow nanospheres. When the SiSE is in situ fabricated on the cathode and applied to LiFePO4/SiSE/Li batteries, the obtained cells show a significant improvement in cycling stability, mainly attributed to the stable electrode/electrolyte interface and remarkable suppression for Li dendrite growth by the SiSE. This work can extend the application of hollow nanooxide and enable a safe, efficient operation of Li anode in next generation energy storage systems.
323 citations
TL;DR: This work proposes and demonstrates facile solution synthesis of a series of colloidal organometal halide perovskite CH3NH3PbX3 (X = halides) nanoparticles with amorphous structure, which exhibit high quantum yield and tunable emission from ultraviolet to near-infrared in light-emitting devices.
Abstract: Organometal halide perovskite has recently emerged as a very promising family of materials with augmented performance in electronic and optoelectronic applications including photovoltaic devices, photodetectors, and light-emitting diodes. Herein, we propose and demonstrate facile solution synthesis of a series of colloidal organometal halide perovskite CH3NH3PbX3 (X = halides) nanoparticles with amorphous structure, which exhibit high quantum yield and tunable emission from ultraviolet to near-infrared. The growth mechanism and photoluminescence properties of the perovskite amorphous nanoparticles were studied in detail. A high-efficiency green-light-emitting diode based on amorphous CH3NH3PbBr3 nanoparticles was demonstrated. The perovskite amorphous nanoparticle-based light-emitting diode shows a maximum luminous efficiency of 11.49 cd/A, a power efficiency of 7.84 lm/W, and an external quantum efficiency of 3.8%, which is 3.5 times higher than that of the best colloidal perovskite quantum-dot-based lig...
310 citations
TL;DR: In this paper, the effect of moisture and CO2 contaminants on Li-O2 batteries is reviewed and the mechanistic understanding of discharge/charge process in O2 at controlled level of moisture or CO2 is illustrated.
Abstract: Lithium-air batteries have become a focus of research on future battery technologies. Technical issues associated with lithium-air batteries, however, are rather complex. Apart from the sluggish oxygen reaction kinetics which demand efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts, issues are also inherited from the nature of an open battery system and the use of reactive metal lithium as anode. Lithium-air batteries, which exchange oxygen directly with ambient air, face more challenges due to the additional oxidative agents of moisture, carbon dioxide, etc. which degrade the metal lithium anode, deteriorating the performance of the batteries. In order to improve the cycling performance one must hold a full picture of lithium-oxygen electrochemistry in the presence of carbon dioxide and/or moisture and fully understand the fundamentals of chemistry reactions therein. Recent advances in the exploration of the effect of moisture and CO2 contaminants on Li-O2 batteries are reviewed, and the mechanistic understanding of discharge/charge process in O2 at controlled level of moisture and/or CO2 are illustrated. Prospects for development opportunities of Li-air batteries, insight into future research directions, and guidelines for the further development of rechargeable Li-air batteries are also given.
281 citations
TL;DR: It is reported that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs).
Abstract: The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN4 /GN is a highly active and stable counter electrode for the interconversion of the redox couple I(-) /I3 (-) . DFT calculations revealed that the superior properties of CoN4 /GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN4 /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart.
238 citations
TL;DR: An innovative, easy, and green method was presented to synthesize an electromagnetic functionalized Ni/carbon foam, in which the formation of Ni nanoparticles and carbon occurred simultaneously from an affordable alginate/Ni(2+) foam precursor.
Abstract: Electromagnetic microwave absorption materials have attracted a great deal of attention. Foams for the low density and tunable porosity are considered as ideal microwave absorbents, while with the requirement of improving their inherent electromagnetic properties. In this manuscript, an innovative, easy, and green method was presented to synthesize an electromagnetic functionalized Ni/carbon foam, in which the formation of Ni nanoparticles and carbon occurred simultaneously from an affordable alginate/Ni2+ foam precursor. The resultant Ni/carbon foam had a low density (0.1 g/cm–3) and high Ni nanoparticles loading (42 wt %). These Ni nanoparticles with a diameter of about 50–100 nm were highly crystallized and evenly embedded in porous graphite carbon without aggregation. Also, the resultant foam had a high surface area (451 m2 g–1) and porosity and showed a moderate conductivity (6 S/m) and significant magnetism. Due to these special characteristics, the Ni/carbon foam exhibited greatly enhanced microwav...
234 citations
TL;DR: Flexible N-functionalization methodologies involving different N-X bond formation have not only provided an efficient approach to diverse energetic ingredients but also expanded the application scope of energetic materials.
Abstract: ConspectusNitrogen-rich heterocycles represent a unique class of energetic frameworks featuring high heats of formation and high nitrogen content, which have generated considerable research interest in the field of high energy density materials (HEDMs). Although traditional C-functionalization methodology of aromatic hydrocarbons has been fully established, studies on N-functionalization strategies of nitrogen-containing heterocycles still have great potential to be exploited by virtue of forming diverse N–X bonds (X = C, N, O, B, halogen, etc.), which are capable of regulating energy performance and the stability of the resulting energetic compounds. In this sense, versatile N-functionalization of N-heterocyclic frameworks offers a flexible strategy to meet the requirements of developing new-generation HEDMs. In this Account, the role of strategic N-functionalization in designing new energetic frameworks, including the formation of N–C, N–N, N–O, N–B and N–halogen bonds, is emphasized.In the family of N-...
229 citations
TL;DR: In this paper, a bottom-up self-assembly approach was used to synthesize Co3O4 nanosheets with a graphene-like holey structure for the oxygen evolution reaction (OER).
176 citations
TL;DR: A new mercury selenide BaHgSe2 was synthesized, which displays a large nonlinear optical (NLO) response and melts congruently.
Abstract: A new mercury selenide BaHgSe2 was synthesized. This air-stable compound displays a large nonlinear optical (NLO) response and melts congruently. The structure contains chains of corner-sharing [HgSe3]4– anions in the form of trigonal planar units, which may serve as a new kind of basic functional group in IR NLO materials to confer large NLO susceptibilities and physicochemical stability. Such trigonal planar units may inspire a path to finding new classes of IR NLO materials of practical utility that are totally different from traditional chalcopyrite materials.
151 citations
TL;DR: This work provides a facile and purposeful approach for developing MOFs toward a highly efficient and selective extraction of uranium(VI) in aqueous solution, and it further facilitates the structure-based design of nanomaterials for radionuclide-containing-medium pretreatment.
Abstract: A novel carboxyl-functionalized metal–organic framework for highly efficient uranium sorption was prepared through a generic postsynthetic strategy, and this MOF’s saturation sorption capacity is found to be as high as 314 mg·g–1 The preliminary application illustrated that the grafted free-standing carboxyl groups have notably enhanced the sorption of uranyl ions on MIL-101 In addition, we have performed molecular dynamics simulation combined with density functional theory calculations to investigate the molecular insights of uranyl ions binding on MOFs The high selectivity and easy separation of the as-prepared material have shown tremendous potential for practical applications in the nuclear industry or radioactive water treatment, and the functionalized MOF can be extended readily upon the versatility of click chemistry This work provides a facile and purposeful approach for developing MOFs toward a highly efficient and selective extraction of uranium(VI) in aqueous solution, and it further facili
147 citations
TL;DR: In this paper, the authors used expanded graphite (EG) and carbon fiber (CF) fillers for thermally conductive form-stable phase change materials (FSPCMs).
TL;DR: A dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry is designed, which enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.
Abstract: We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. It thus enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.
TL;DR: Highly efficient flame retardant polyurethane foams with alginate/clay aerogel coatings fabricated using a freeze-drying method indicate significantly reduced fire risk and could expand its fire safe applications.
Abstract: Highly efficient flame retardant polyurethane foams with alginate/clay aerogel coatings were fabricated using a freeze-drying method. The microstructure and the interaction of the samples were characterized with scanning electron and optical microscopy (SEM) and (OM). The results show that PU foam has a porous structure with pore sizes of several hundred microns, and that of aerogel ranges from 10 to 30 μm. The PU foam matrix and the aerogel coatings have strong interactions, due to the infusion of aerogel into the porous structure of the foam and the tension generated during the freeze-drying process. Both the PU foam and the aerogel exhibit good thermal stabilities, with onset decomposition temperatures above 240 °C. Combustion parameters, including LOI, TTI, HRR, TSR, FIGRA, CO, and CO2, all indicate significantly reduced fire risk. Total heat release of all but one of the samples was maintained, indicating that the flame retardant mechanism is to decrease flame spread rate by forming a heat, oxygen, a...
TL;DR: An undulator-based vacuum ultraviolet (VUV) beamline (BL03U), intended for combustion chemistry studies, has been constructed at the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China and the ability to detect reactive intermediates is advantageous in combustion chemistry research.
Abstract: An undulator-based vacuum ultraviolet (VUV) beamline (BL03U), intended for combustion chemistry studies, has been constructed at the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China. The beamline is connected to the newly upgraded Hefei Light Source (HLS II), and could deliver photons in the 5–21 eV range, with a photon flux of 1013 photons s−1 at 10 eV when the beam current is 300 mA. The monochromator of the beamline is equipped with two gratings (200 lines mm−1 and 400 lines mm−1) and its resolving power is 3900 at 7.3 eV for the 200 lines mm−1 grating and 4200 at 14.6 eV for the 400 lines mm−1 grating. The beamline serves three endstations which are designed for respective studies of premixed flame, fuel pyrolysis in flow reactor, and oxidation in jet-stirred reactor. Each endstation contains a reactor chamber, an ionization chamber where the molecular beam intersects with the VUV light, and a home-made reflectron time-of-flight mass spectrometer. The performance of the beamline and endstations with some preliminary results is presented here. The ability to detect reactive intermediates (e.g. H, O, OH and hydroperoxides) is advantageous in combustion chemistry research.
TL;DR: In this article, the screw-like SnO2 nanostructures were constructed by growing thread-like nanosheets onto rod-like single-crystalline nanowires, which offers an efficient light absorption, high speed electron transport and a large surface to volume ratio.
TL;DR: In this article, an enhanced theoretical model of the displacement amplification ratio for both the bridge-type and rhombus-type compliant mechanisms is proposed to improve the prediction accuracy based on the distinct force analysis between these two flexures.
Abstract: Piezo-actuated, flexure hinge-based compliant mechanisms have been frequently used in precision engineering in the last few decades. There have been a considerable number of publications on modeling the displacement amplification behavior of rhombus-type and bridge-type compliant mechanisms. However, due to an unclear geometric approximation and mechanical assumption between these two flexures, it is very difficult to obtain an exact description of the kinematic performance using previous analytical models, especially when the designed angle of the compliant mechanisms is small. Therefore, enhanced theoretical models of the displacement amplification ratio for rhombus-type and bridge-type compliant mechanisms are proposed to improve the prediction accuracy based on the distinct force analysis between these two flexures. The energy conservation law and the elastic beam theory are employed for modeling with consideration of the translational and rotational stiffness. Theoretical and finite elemental results show that the prediction errors of the displacement amplification ratio will be enlarged if the bridge-type flexure is simplified as a rhombic structure to perform mechanical modeling. More importantly, the proposed models exhibit better performance than the previous models, which is further verified by experiments.
TL;DR: In this article, the authors investigated the dynamic damage and fracture behavior of concrete under compression with strain rate up to 100 ǫ s−1 by Monte Carlo simulations (MCSs) of realistic meso-scale models based on high-resolution micro-scale X-ray computed tomography (XCT) images.
TL;DR: A facile fabrication of high-performance flexible all-solid-state carbon micro-supercapacitors with highly improved energy and power densities is demonstrated by laser direct writing on polyimide films using a 405nm blue-violet semiconductor laser in an Ar atmosphere.
TL;DR: It is demonstrated that the intrinsic band offset at the CH3NH3PbI3/MoS2 interface can be overcome by creating sulfur vacancies in MoS2 using a mild plasma treatment, and highlights the feasibility of applying defect-engineered 2-D TMDCs as charge-extraction layers in perovskite-based optoelectronic devices.
Abstract: The performance of a photovoltaic device is strongly dependent on the light harvesting properties of the absorber layer as well as the charge separation at the donor/acceptor interfaces. Atomically thin two-dimensional transition metal dichalcogenides (2-D TMDCs) exhibit strong light–matter interaction, large optical conductivity, and high electron mobility; thus they can be highly promising materials for next-generation ultrathin solar cells and optoelectronics. However, the short optical absorption path inherent in such atomically thin layers limits practical applications. A heterostructure geometry comprising 2-D TMDCs (e.g., MoS2) and a strongly absorbing material with long electron–hole diffusion lengths such as methylammonium lead halide perovskites (CH3NH3PbI3) may overcome this constraint to some extent, provided the charge transfer at the heterostructure interface is not hampered by their band offsets. Herein, we demonstrate that the intrinsic band offset at the CH3NH3PbI3/MoS2 interface can be o...
TL;DR: In this article, a flexible all-solid-state fiber supercapacitor was developed by using Ti/TiO2/MoS2 coaxial fiber electrodes that consist of MoS2 nanosheets grown on titanium wires by a TiO2 buffer layer assisted hydrothermal growth strategy.
TL;DR: In this paper, fire-resistant, low-cost, high-porosity foamed concretes, which have desirable thermal-insulation properties and can be cast in-place, were prepared by adding preformed foam to ordinary Portland-cement slurries.
TL;DR: In this paper, a review of broadband optical limiting (OL) materials and processes for laser protection is presented, where the dominant limiting mechanism of graphene is nonlinear scattering, which is very effective in liquid suspensions rather than in solid state hosts.
TL;DR: SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China as mentioned in this paper, which can deliver 180kJ energy and 60TW power ultraviolet laser onto target, with power balance better than 10%.
Abstract: SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.
TL;DR: A short overview of colorimetric and fluorescence detection with gold nanoparticle (AuNP) sensors of chemical warfare agents (CWAs) is provided in this article, which includes nerve agents, vesicant agents, pulmonary agents, cytotoxic proteins, suffocating/blood agents, incapacitating agents, and lachrymatory.
TL;DR: In this article, a new coagulation bath with CaCl2 in aqueous solution for preparing meter-long PEDOT:PSS fibers with good mechanical properties can be easily woven, sewed, knotted and braided as the YSC electrode.
Abstract: Recently, fiber-shaped yarn supercapacitors (YSCs) have attracted extensive attention due to their merits of small volume, high flexibility and potential to be woven in textiles for future wearable electronics. PEDOT:PSS possesses properties of high-redox capacitance, high conductivity and high intrinsic flexibility, so PEDOT:PSS yarn electrodes are quite promising in the field of YSCs. However, to the best of our knowledge, twisted yarns based on wetspun PEDOT:PSS fibers for fiber-shaped YSCs have not been reported. Herein, we develop a new coagulation bath with CaCl2 in aqueous solution for preparing meter-long PEDOT:PSS fibers. The PEDOT:PSS fibers with good mechanical properties can be easily woven, sewed, knotted and braided as the YSC electrode. The PEDOT:PSS fiber-based YSCs show a high areal capacitance of 119 mF cm−2 and areal energy density of 4.13 μW h cm−2. Meanwhile, the all-solid-state YSCs are flexible and robust enough to tolerate the long-term and repeated bending without an obvious capacitance drop.
TL;DR: This study applies all four approaches to simulate pore-scale velocity distributions and (for capable codes) nonreactive solute transport, and applies intercomparison work to allow consistent comparison of flow and transport simulations across the full suite of methods.
TL;DR: In this paper, a facile and cost-effective method for the fabrication of all-solid-state flexible carbon micro-supercapacitors (MSC) was demonstrated by laser direct writing on polyimide (PI) sheets with a compact and low-cost 405 nm semiconductor blue-violet laser, the beam of which was almost totally absorbed in the PI sheet.
Abstract: A facile and cost-effective method for the fabrication of all-solid-state flexible carbon micro-supercapacitors (MSC) was demonstrated by laser direct writing on polyimide (PI) sheets with a compact and low-cost 405 nm semiconductor blue-violet laser, the beam of which was almost totally absorbed in the PI sheet. The obtained MSCs exhibit high performances due to the hierarchical porous structures and large thickness. Furthermore, surface treatment by air-plasma etching was employed to improve the contact interface between the carbon structures and the electrolyte, which may also influence pore structures, thus largely enhancing the MSC performance. The typical MSCs after plasma treatment for 100 s show an improved specific capacitance as high as 18.3 mF cm−2 at a scan rate of 10 mV s−1 and 31.9 mF cm−2 at a current density of 0.05 mA cm−2, both of which are higher than most of the carbon material-based MSCs reported till now. Moreover, the MSCs show good flexibility, long-time cycle stability, as well as temperature tolerance up to 80 °C. In addition, the voltage and capacitance can be scaled up by simply connecting a single MSC in series, parallel or both. The facile fabrication, low cost, and good performance make carbon-based MSCs fabricated by semiconductor laser direct writing promising candidates for on-chip energy storage devices.
TL;DR: In this paper, a unified method is presented for the vibration analysis of the plates mentioned above with general boundary conditions based on the first-order shear deformation theory and Ritz procedure.
Abstract: The vibrations of functionally graded circular plates, annular plates, and annular, circular sectorial plates have been traditionally treated as different boundary value problems, which results in numerous specific solution algorithms and procedures. It is the problem itself that has been an overwhelming task for a new researcher or application engineer to comprehend. Furthermore each type of plate usually needs treating separately when different boundary conditions are involved. In this paper, a unified method is presented for the vibration analysis of the plates mentioned above with general boundary conditions based on the first-order shear deformation theory and Ritz procedure. The material properties are assumed to vary continuously through the thickness according to the general four-parameter power-law distribution. Regardless of the shapes of the plates and the types of boundary conditions, the displacements of the plates are described as an improved Fourier series expansion which is composed of a double Fourier cosine series and several auxiliary functions. As an innovative point of this work, the auxiliary functions are introduced to eliminate all the relevant discontinuities with the displacement and its derivatives at the boundaries and to accelerate the convergence of series representations. The accuracy, reliability and versatility of the current solution are fully demonstrated and verified through numerical examples involving plates with various shapes and boundary conditions. Some new results of functionally graded circular, annular and sector plates with various boundary conditions are presented, which may serve as datum solutions for future computational methods. In addition, the influence of boundary conditions, the material and geometric parameters on the vibration characteristics of the plates are also reported.
TL;DR: In this article, a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields was proposed to increase the laser coupling efficiency and improve the capsule symmetry and mitigate the influence of the wall blowoff on laser transport.
TL;DR: By a series of motivated and closely linked calculations, this work tries to provide a portable method, by which researchers could gain insights into the physicochemical properties of solid electrolyte.
Abstract: The improved ionic conductivity (1.64 × 10(-4) S cm(-1) at room temperature) and excellent electrochemical stability of nanoporous β-Li3PS4 make it one of the promising candidates for rechargeable all-solid-state lithium-ion battery electrolytes. Here, elastic properties, defect thermodynamics, phase diagram, and Li(+) migration mechanism of Li3PS4 (both γ and β phases) are examined via the first-principles calculations. Results indicate that both γ- and β-Li3PS4 phases are ductile while γ-Li3PS4 is harder under volume change and shear stress than β-Li3PS4. The electrochemical window of Li3PS4 ranges from 0.6 to 3.7 V, and thus the experimentally excellent stability (>5 V) is proposed due to the passivation phenomenon. The dominant diffusion carrier type in Li3PS4 is identified over its electrochemical window. In γ-Li3PS4 the direct-hopping of Lii(+) along the [001] is energetically more favorable than other diffusion processes, whereas in β-Li3PS4 the knock-off diffusion of Lii(+) along the [010] has the lowest migration barrier. The ionic conductivity is evaluated from the concentration and the mobility calculations using the Nernst-Einstein relationship and compared with the available experimental results. According to our calculated results, the Li(+) prefers to transport along the [010] direction. It is suggested that the enhanced ionic conductivity in nanostructured β-Li3PS4 is due to the larger possibility of contiguous (010) planes provided by larger nanoporous β-Li3PS4 particles. By a series of motivated and closely linked calculations, we try to provide a portable method, by which researchers could gain insights into the physicochemical properties of solid electrolyte.