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151.
Au‐Decorated Cracked Carbon Tube Arrays as Binder‐Free Catalytic Cathode Enabling Guided Li2O2 Inner Growth for High‐Performance Li‐O2 Batteries
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Fangfang Tu Junping Hu Jian Xie Gaoshao Cao Shichao Zhang Shengyuan A. Yang Xinbing Zhao Hui Ying Yang 《Advanced functional materials》2016,26(42):7725-7732
Owing to their extremely high energy density, Li‐O2 batteries have attained increasing attention in recent studies. However, deposition of the discharge product, insulating Li2O2, is known to seriously limit the electrochemical performance of Li‐O2 batteries. While extensive studies have focused on relieving electrode deactivation by controlling Li2O2 growth, no permanent or effective mechanism is delivered. Here, a unique design comprising a catalytic cathode constructed by cracked carbon submicron tube (CST) arrays decorated with Au nanoparticles on inner walls is proposed. The introduction of Au nanoparticles not only improves electrode conductivity but also provides catalytic sites, guiding conformal growth of thin‐layered Li2O2 inside the cracked CST. Density functional theory calculations support that Au decoration on CST favors the conformal growth of Li2O2 on inner tubular walls. This growth behavior of Li2O2 renders easy decomposition of Li2O2, prevents carbon tube electrode from full, rapid deactivation, and preserves the free space for reactants transport. Li‐O2 cells with Au@CST exhibit good rate capability (1208 mAh g–1 at a high current density of 1000 mA g–1) and long cycle life (112 cycles at a current density of 400 mA g–1 with a limited capacity of 500 mAh g–1). 相似文献
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A flow injection micro-analyser with an integrated injection device and photometric detection is described. Channels measuring 205-295 μm depth by 265-290 μm maximum width were manufactured by deep UV lithography on two layers of urethane-acrylate oligomers-based photoresist. Hypodermic syringe needles (450 μm diameter) were connected to the channels for introduction of solutions into the system. Plastic optical fibres were connected to the ends of a 5.0 mm long channel, in order to conduct the light from and to a homemade photometer. The device has a total volume of 7.0 μL and three different sample volumes (0.09, 0.22 and 0.30 μL) can be inserted into the system by choosing the appropriate loop of the hydrodynamic injection approach. The micro-analyser, designed as a single line manifold, was evaluated by determining chloride in waters (mercuric thiocyanate method), and chromium (VI) in wastewater and total chromium in metallic alloys (diphenylcarbazide method). For chloride determination two micro-pumps were employed to impel the solutions, while for chromium determination this task was performed by a conventional peristaltic pump. The results obtained in all determinations did not differ significantly from the reference methods at a confidence level of 95%. In the chloride determination, a flow rate of 50 μL min−1 was used, providing a sample frequency of 45 injection h−1, generating ca. 0.7 mg of Hg(II) after an 8-h working day (ca. 20 mL of solution). This result suggests the potential of the micro-analyser towards the reduction of waste, following the philosophy of Green Chemistry. 相似文献
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Application of Solid Immersion Lens to Submicron Resolution Imaging of Nano-Scale Quantum Wells 总被引:1,自引:0,他引:1
We have discussed the resolution of submicron photoluminescence (PL) imaging using a solid immersion lens (SIL), which collects an evanescent light field. We apply the SIL microscope to measure PL image of a strip-line-patterned GaAs quantum well structure at low temperature. An improved resolution beyond diffraction limit and high collection efficiency of PL are realized.This paper was originally presented at the 5th International Conference on NEAR FIELD OPTICS and RELATED TECHNOLOGIES (NFO-5), which was held on December 6–10, 1998 at Coganoi Bay Hotel, Shirahama, Japan, in cooperation with the Japan Society of Applied Physics and Mombusho Grant-in Aid for Scientific Research on Priority Areas “Nearfield Nano-optics” Project, sponsored by Japan Society for the Promotion of Science. 相似文献
157.
激光直写中光刻胶对激光能量的吸收模型 总被引:1,自引:0,他引:1
光刻胶对激光能量的吸收模型是激光直写中的重要模型,它是进行邻近效应计算机模拟进而实现邻近校正不可缺少的重要依据。分析了影响光刻胶吸收激光束能量的主要因素,提出了一种光刻胶对激光能量的吸收模型。实验表明,该模型能更精确地表示光刻胶吸收激光能量密度分布的实际情况,能为激光直写邻近校正及微光学元件等光刻过程的计算机模拟提供可靠的依据。 相似文献
158.
Keunjoo Kim Hong Seub Kim Hwack Joo Lee 《Journal of Solid State Electrochemistry》1999,3(7-8):417-423
The thermionic hole emissions from a p-type Si0.67Ge0.33 quantum well with a width of 7 nm and a point defect were investigated using deep level transient spectroscopy. An activation
energy of 0.22 eV from the quantum well is consistent with the heavy hole level from the bottom of the well. The defect-related
band with an energy of 0.30 eV originated from the space charge related to the point defect in the vicinity of the quantum
well heterostructure. The origin of the point-defect-related band was confirmed by photoluminescence and the deep level was
further clarified by using capacitance-voltage measurements and simulation by introducing a simple model of an interfacial
hole trap center. The deep hole trap center apparently disappeared by an annealing effect, indicating that point defects are
subject to thermal annealing. The microscopic measurement provides evidence on point defects in the quantum well structure
and the thermal annealing also enhances the thermionic hole emission from the quantum well structure.
Received: 22 August 1998 /Accepted: 15 February 1999 相似文献
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