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Lithium ion capacitors (LICs) are deemed to be an ideal complement between lithium-ion batteries and supercapacitors. However, the sluggish kinetics that leads to a poor rate capability of Faradaic insertion anodes remains a handicap. Herein, a self-supported architecture is designed by combining an interconnected graphene scroll (GS) framework with in situ formed well-distributed MnO nanoparticles (NPs) for an advanced LIC anode. In this architecture, the inner-connected tubular GS framework plays a multifunctional role: serving as an electron transport bridge like “highways”, providing a favorable ion transport pathway as well as accommodating the volume expansion and maintaining the structural stability of MnO. Benefiting from the stable structure, highly localized charge-transfer and low energy diffusion barrier, the as-built anode exhibits an ultrahigh-rate behavior (203 mAh g−1 at 20 A g−1) and robust cycling stability (759 mAh g−1 after 1000 cycles at 2 A g−1). When evaluated as a self-supported anode for LIC, the LIC delivers a high energy density of 179.3 Wh kg−1, a high power density of 11.7 kW kg−1, and a capacity retention of 80.8% after 5000 cycles. Moreover, the corresponding soft-packaged LIC keeps stable electrochemical performances at various bending states. All these features manifest the potential of the architecture for application in advanced energy storage devices.

In this work, we put forward an effective approach by combining both highly transparent and conductive carbon nanotube (CNT) network and poly (3, 4-ethylene dioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) film to co-form-coordinate heterojunctions with silicon, and have developed a hybrid PEDOT:PSS-CNT/n-Si solar cell. The power conversion efficiency (PCE) of the as-designed solar cell can be improved up to 10.2%, which is much higher than the PCE values of both PEDOT:PSS/n-Si (5.5%) and CNT/n-Si (6.1%) solar cells fabricated using the same materials and process. PEDOT:PSS can fill the hundreds nanometer scale pores of the CNT network, both CNT network and PEDOT:PSS patches contact with the silicon concomitantly and form p Synergy -n heterojunctions through seamless contact with n-Si. The PEDOT:PSS-CNT composite film exhibits a much lower sheet resistance and remains high optical transmittance. Once the photo-generated holes are extracted to the PEDOT:PSS-CNT composite film, CNT network can serve as a carrier transport bridge, which is different from the design that inserts an ultrathin polymer between the CNT and Si. Incorporation of the continuous CNT network with PEDOT:PSS jointly in the as-designed simple and explicit structure has generated synergistic effects, which can make full use of the respective merits and then considerably enhance the PCE of hybrid PEDOT:PSS-CNT/n-Si solar cells.

The experiments have been performed in a horizontal detonation tube having a 13-m-long test section with 224 mm internal diameter. The suspended aluminum particles are spherical with a diameter range of 1–50 μm, using a particle concentration of 300 g/m3 approximately. It is found that the single-front and double-front detonation waves can propagate in a mixture of φ = 1.0 H2–air and aluminum particles which react with water vapor produced by gaseous detonation. The pressure records show that the detonation structure is double front when using 50 or 30 μm aluminum particles and that single front when using 20, 10, or 1 μm ones. However, these single-front detonation waves don’t have the same properties. The detonation velocity using 1 μm particles is increased by 3.3% from the value of the baseline gas detonation as the heat release between particles and gases starts before the sonic surface and supports the shock, while the 10 and 20 μm ones start behind the sonic surface, so the detonation velocities cannot be increased. The single-front structure displayed in pressure records using 10 and 20 μm particles is because of the delay of the second front which is too short to distinguish in the pressure records.

Recent development in epidermal and bionic electronics systems has promoted the increasing demand for supercapcacitors with micrometer-thickness and good compatibility. Here, a highly flexible free-standing epidermal supercapacitor (SC-E) with merely 1 μm thickness and high performance is developed. Single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) hybrid films with unique inner-connected reticulation are adopted as electrodes for ultrathin structure and high electric conductivity. Then, based on two substrates with different surface energies, a stepwise lift-off method is presented to peel off the ultrathin integrated supercapacitor from the substrates nondestructively. As a result of the high conductive hybrid electrodes and the thin electrolyte layer, the as-designed supercapacitors (based on the total mass of two electrodes) achieve a good capacitance of 56 F g−1 and a superhigh power density of 332 kW kg−1, which manifest superior performance in contrast to the other devices fabricated by traditional electrodes. Meanwhile, the ultrashort response time of 11.5 ms enables the epidermal supercapacitor (SC-E) work for high-power units. More importantly, the free-standing structure and outstanding flexibility (105 times bending) endow the SC-E with excellent compatibility to be integrated and work in the next generation of smart and epidermal systems.

In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g(-1). H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.

In this paper, the compactions of the elasto-plastic and the visco-plastic granular assemblies are simulated using the finite element method. Governing equations for motion and deformation for particles, including coupling of rigid body motion and deformation for deformable bodies, are investigated. An implicit discrete element method for block systems is developed to make visco-plastic analysis for the assemblies. Among particles, three different contact types, cohering, rubbing and sliding, are taken into account. To verify accuracy and efficiency of the numerical method, some numerical example is simulated and the results are in a satisfactory agreement with the solutions in literatures. The effects of frictional condition, the initial solid volume ratio, the number of particles in the assembly, and different types of compact- tion on the compaction of the elasto-plastic and the visco-plastic aggregates are investigated. It is demonstrated that the effect of frictional condition, the initial solid volume ratio, the number of particles in the assembly, and different types of compaction on the global behavior of the elasto-plastic the visco-plastic granular assemblies under compacting are considerable. The numerical model is extended to simulate the compaction of aggregates consisting of mixed particles of different viscous incompressible materials. It is indicated that, with minor modification, the method could be used in a variety of problems that can be represented using granular media, such as asphalt, polymers, aluminum, snow, food product, etc.

An ingenious strategy is put forward to evaluate accurately the thermoelectric performance of carbon nanotube (CNT) thin films, including thermal conductivity, electrical conductivity, and Seebeck coefficient in the same direction. The results reveal that the as-prepared CNT interconnected films and CNT fibers possess enormous potential of thermoelectric applications because of their ultrahigh power factors.

Solar cells that combine single-crystalline silicon (Si) with graphene (G) have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency (PCE) of G/Si solar cell without chemical doping is commonly low due to the relatively high resistance of graphene. In this work, through combining graphene with carbon nanotube (CNT) networks, we fabricated three kinds of hybrid nanocarbon film/Si heterojunction solar cells in order to increase the PCE of the graphene based Si solar cell. We investigated the characteristics of different nanocarbon film/Si solar cells and found that their performance depends on the heterojunctions. Specifically, a doping-free G-CNT/Si solar cell demonstrated a high PCE of 7.9%, which is nearly equal to the combined value of two individuals (G/Si and CNT/Si). This high efficiency is attributed to the synergistic effect of graphene and CNTs, and can be further increased to 9.1% after applying a PMMA antireflection coating. This study provides a potential way to further improve the Si based heterojunction solar cells.

Bridged strips consisting of carbon nanotubes and poly(vinylidene fluoride) are developed, which exhibit notable deflection in response to very low driven voltages (), because of both the excellent conductivity of the unique carbon nanotube film and the powerful thermal expansion capability of the polymer. The actuators demonstrate periodic vibrations motivated by the alternating signals. The amplitude of displacement is dependent not only on the driven voltage but also on the applied frequency. The mechanism of actuation is confirmed to be the thermal power induced by the electrical heating. By accelerating the dissipation of heat, the vibration response at higher frequencies can be significantly enhanced. The useful locomotion shows great promise in potential applications such as miniature smart devices and micro power generators.

In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 Ω/ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell (OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly (3-hexylthiophene) (P3HT) and phenyl-C61 butyric acid methyl ester (PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass (2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does.

Vanadium dioxide thin films have been fabricated through sputtering vanadium thin films and rapid thermal annealing in oxygen. The microstructure and the metal—insulator transition properties of the vanadium dioxide thin films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and a spectrometer. It is found that the preferred orientation of the vanadium dioxide changes from (11) to (011) with increasing thickness of the vanadium thin film after rapid thermal annealing. The vanadium dioxide thin films exhibit an obvious metal—insulator transition with increasing temperature, and the phase transition temperature decreases as the film thickness increases. The transition shows hysteretic behaviors, and the hysteresis width decreases as the film thickness increases due to the higher concentration carriers resulted from the uncompleted lattice. The fabrication of vanadium dioxide thin films with higher concentration carriers will facilitate the nature study of the metal—insulator transition.

Rapid, subduction-induced venting of fluids was recently discovered at the lower slopes of several convergent margins. In this study, the authors examine, by numerical modeling, the sources and pathways for the expelled fluids at the lower slope of the Oregon-Washington margin. Models are constructed on the vasis of existing multichannel seismic records, Deep Sea Drilling Project drilling data, and regional tectonic history. They show that the hydrogeologic processes at this margin may be cyclic and episodic. An important fluid source may be the underthrust turbidites beneath the frontal thrust, which dewater under the increasing overburden of the advancing thrust sheet. The underlain hemipelagic unit, on the other hand, is a poor source of fluid, even though it is highly pressurized. Since the dewatering turbidites have not been subjected to temperatures greater than 100C, the above conclusion is consistent with the low-temperature signatures in the carbon isotope data for vented fluids and carbonate cementation at the lower slope. Cyclic but episodic seaward migration of the frontal thrust of the accretionary complex leads to corresponding seaward migration of the fluid sources. Between the distinct thrusting episodes, the fluid sources grow both in size and pore pressure in response to the increasing overburdenmore » of the advancing frontal thrust. Other factors being equal, thrusting at the landward vergent margin is more effective in creating fluid sources than thrusting at the seaward vergent margin. Some aspects of these inferences may be common to other similar convergent margins and are testable with future Ocean Drilling Program drilling.« less