To further understand the underlying physical mechanisms of dealloying of multiphase alloys and control dissolution processes among different phases, the dealloying behavior of melt-spun Al 40 atom % Cu alloy comprising Al 2 Cu and AlCu intermetallic compounds in a 10 wt % sodium hydroxide ͑NaOH͒ aqueous solution was studied. The microstructure of as-dealloyed samples was characterized using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray analysis. The experimental results show that the alloy with the amount of Al 2 Cu comparable to that of AlCu can be partially dealloyed, which eventually results in the formation of a unique kind of nanoporous copper/AlCu composite. Additionally, the formation mechanism has been well established to describe the morphology and composition evolutions during the dealloying process based upon kinetic competitions between dissolution of Al atoms and diffusion-rearrangement of Cu atoms, which includes three stages, sequentially, defined as "Al 2 Cu dealloying," "AlCu dealloying," and "coarsening accompanying underlying AlCu re-dealloying." © 2010 The Electrochemical Society. ͓DOI: 10.1149/1.3511771͔ All rights reserved.Manuscript submitted September 13, 2010; revised manuscript received October 13, 2010. Published December 16, 2010 Nanoporous metals with large surface area have recently attracted considerable interest in a wide variety of applications including catalysis, sensors, actuators, fuel cells, microfluidic flow controllers, and so forth.1-4 For a long time, template methods are commonly used to fabricate these materials through the replication of porous alumina or liquid-crystal templates. [5][6][7] Because it has been found that dealloying can be used to yield a broad range of porous metals, during recent decades, a great deal of effort has been directed toward the investigation of nanoporous metals prepared through dealloying. [8][9][10][11] However, most of the previously reported porous metals were fabricated by dealloying from binary/ternary alloy systems with a single-phase solid solubility across all compositions, which refer to selective dissolution of one or more active components out of an alloy, such as Cu-Pt, Ag-Au, Cu-Au, and Au-Ag-Pt. [12][13][14][15] In view of their industrial applications, widespread uses of a dealloying technique to make nanoporous metals are frequently hindered by the high cost of these noble metals and limited alloy systems. Thus, the fabrication of nanoporous materials from alloy families based on common metals with multiple phases urgently needs to be investigated.However, a few substantial researches have so far focused on this topic using an electrochemical/chemical dealloying technique because of the difficulties in clarifying dealloying behavior and controlling the dissolution process among different phases in multiphase alloys. 16 Recently, Qi et al. 17 reported that the uniform nanoporous copper ͑NPC͒ with a pore size of several hundred nanometers can be synthesized from dual-phase Al-Cu alloys with a ...

Well-aligned TiO2 nanotube arrays were fabricated from anodization by a subsequent heat treatment. Rate performance and electrochemical properties of TiO2 nanotube arrays were studied intensively. The electrode exhibits excellent rate capabilities at various rates with an average coulombic efficiency reaching 95.6%. It is obvious that TiO2 nanotube array possesses high rate capability and excellent cycling stability.

Solid polymer electrolytes (SPEs) which were composed of poly (ethylene oxide) (PEO), poly (lithium acrylate) (PLiAA), and LiClO4were prepared in order to investigate the influence of LiClO4content on the ionic conductivity of the electrolyte. All of the membranes were investigated by XRD, DSC, and EIS, et.al. The dependence of SPEs conductivity on temperature was measured, and the maximum ionic conductivity is 5.88×10-6S/cm at 293 K for membrane which is composed of PEO+PLiAA+15wt% LiClO4. The electrochemical stability window of the PEO+PLiAA+15wt% LiClO4is 4.75 V verse Li.

The Li/S polymer secondary batteries presents higher capacity, lower materials cost and much better performance in higher operation temperature. A nano-scale sulfur polymer composite cathode material has been developed for these batteries, and its cycle capacity is over 700mAh/g when the lithium metal is used as the anode; A nano-scale Cu/Sn alloy powder has been synthesized by a novel micro-emulsion process, its cycle capacity is over 300 mAh/g; The performance of PVdF gel electrolyte has been improved through the addition of the nanometer SiO2 synthesized in-situ. The advanced Li/S polymer secondary batteries will be a promising alternative for next generation energy storage system.

Tin nano-spheres film was synthesized by electrodeposition based on the copper-nickel nano-pillars which were prepared by electrochemical method on the copper foil in an aqueous solution containing Cu (II) and Ni (II) at room temperature. The morphology, structure and composition of the as-prepared copper-nickel nano-pillars and tin nano-spheres were characterized by SEM, XRD, and EDS. The tin nano-spheres film anode features the large surface area, good electronic conductivity, and adhesion with the current collector, leading to the enhanced performance in lithium-ion batteries.

Spherical LiNi0.8Co0.2O2 powders with particle size of 8~10μm were prepared based on controlled crystallization, and coated with Al2O3 by Al(OH)3 sol, that was prepared from Al(NO3)3 and NaOH, at first time. SEM, XRD and surface element analysis showed that the nano-sized Al2O3 was coated uniformly on the surface of LiNi0.8Co0.2O2 powder. At 25 °C, the initial discharge capacity decreased from 160 to 149 mAh g-1 after coating of Al2O3. The initial discharge capacity decreased from 168 to 163 mAh g-1 after coating of Al2O at 55 °C. After coating of Al2O3, the capacity retentions increased from 83.8% to 92.6% at the 50th cycle at 25°C, and from 36.3% to 90.8% at the 10th cycle at 55°C. This paves effective way to improve the performance of LiNi0.8Co0.2O2 material for rechargeable lithium ion batteries.

AuNi alloy was synthesized by vacuum arc melting in high-purity argon atmosphere. The AuNi alloy was characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The results of EDS indicated that Au and Ni atoms were well-distributed in the alloy. Moreover, the results of XPS exhibited an electronic transfer from Ni to Au in AuNi phase. The Electrocatalytic oxygen reduction reaction (ORR) activity and the methanol tolerance of the AuNi alloy were respectively investigated using the RDE method and the electrochemical cyclic voltammetry. The results suggested that O2was directly oxidized to H2O on the AuNi catalyst via an approximate four-electron reduction pathway, and that the AuNi catalyst had a high electrocatalytic activity for the ORR and an acceptable methanol tolerance, simultaneously.

Preparation and performance of poly(acrylonitrile-methylmethacrylate) based microporous gel electrolyte for Li-ion batteries were studied. The poly(acrylonitrile-methyl methacrylate (P(AMMA)) was synthesized by suspension polymerization, and poly(acrylonitrile-methyl methacrylate) microporous polymer membrane with 0.03~0.1mm was prepared by phase inversion technique. The gel electrolyte was obtained by putting the P(AMMA) microporous polymer membrane in a liquid electrolyte, which was a solution of 1.0 M LiPF6 dissolved in a 1:1 (v/v) mixture of ethylene carbonate (EC) and diethylene carbonate (DEC, and heated at 60°C for 2 hours. The microporous gel electrolyte gelled with 325 wt.% of liquid electrolyte vs. the dried membrane presented an ionic conductivity of 7.52 × 10-4 S/cm at 25°C. The coin test battery with the microporous gel electrolyte showed a good cycling performance. The discharge capacity retention was above 88% at 0.1C rate at the 50th cycle.