The process for the site-controlled formation of tunnel pits with high aspect ratios by anode etching of Al͑100͒ foil is described.Introduction of a small amount of Cu on the Al foil, which has a patterned thin layer of polymers, initiated the uniform development of pits and generated the tunnel pits with sufficiently high aspect ratios. The obtained ordered array of tunnel pits with high aspect ratios will be used for the preparation of several types of functional devices in addition to the improvement of electrolytic capacitors, which use the Al foil with tunnel pits as a surface-enlarged electrode.Formation of tunnel pits on Al by the anisotropic anode etching of Al͑100͒ foils in an electrolyte containing Cl − ions has been widely used for the enlargement of the surface area of electrodes in electrolytic capacitors. 1-10 To maximize the capacitance of the electrolytic capacitors, the size and interval of the tunnel pits must be controlled precisely by considering the operating voltages. 1 In our previous report, we showed the control of the initiation sites of the tunnel pits using a patterned mask composed of a polymer film on Al. 11 In this process, a very thin patterned mask of poly͑chloro-prene͒ rubber ͑CR͒ with the thickness of ϳ200 nm formed on Al can be used to control the initiation of tunnel pits at the initial stage of the anode etching of Al. However, tunnel pits with sufficient depth could not be formed due to the preferential growth of the tunnel pit in the lateral directions. In the present report, we show the process for the formation of tunnel pits with sufficiently high aspect ratios. For the uniform growth of tunnel pits with high aspect ratios, we introduced a small amount of Cu on an Al surface as an initiator for the uniform development of tunnel pits. The uniform development of the pits effectively improved their growth with uniform depth, and yielded the tunnel pits with sufficiently high aspect ratios. The obtained ordered array of tunnel pits on Al prepared by the present process will be used for the fabrication of various types of functional devices in addition to the improvement of the capacitance in electrolytic capacitors. Figure 1 shows the process for the fabrication of highly ordered tunnel pits with high aspect ratios on Al. A patterned mask composed of a polymer film placed on Al with the ͑100͒ plane ͑Ͼ95%͒ was formed using a process reported previously. 11 A thin patterned mask of CR was formed using a poly͑dimethylsiloxane͒ ͑PDMS͒ stamp, which has an ordered hole array. Diameter, depth and interval of holes of the stamp were 1.5, 1.5, and 5.0 m, respectively. Size of the stamp was typically 6 ϫ 6 mm. Before making a patterned mask, an Al foil was electrochemically polished in a mixed solution of perchloric acid and ethanol. Then, a small amount of Cu was formed on the surface of Al by vacuum evaporation or sputtering. The amount of deposited Cu was controlled using a quartz crystal thickness monitor. Electrochemical etching of Al was carried out under a constant-current cond...

SDX ® which is surface coated aluminum current collector (AL) with carbon black and organic binder, makes a cell resistance lower and adhesion between cathode active material and AL stronger, so as to improve battery performances dramatically. The cell resistance was separated simply into electronic resistance and ionic resistance. We successfully separated the electronic resistance into material resistance and interface resistance between cathode active material and AL. And then, we independently measured the material resistance and the interface resistance by Electrode Resistance Meter (HIOKI E.E. CORPORATION) which can separate electrode resistance into material and interface resistance. In this paper, more detailed examinations were carried out, and the mechanism of decreasing resistance by SDX ® in lithium ion battery (LIB) was tried to be clarified.

SDX ® which is surface coated aluminum current collector (Al) with carbon black and organic binder, makes a cell resistance lower and adhesion between cathode active material and Al stronger, so as to improve battery performances dramatically. The cell resistance was separated simply into electronic resistance and ionic resistance. We successfully separated the electronic resistance into material resistance and interface resistance between cathode active material and Al. And then, we independently measured the material resistance and the interface resistance by Electrode Resistance Meter (HIOKI E.E. CORPORATION) which can separate electrode resistance into material and interface resistance. In this paper, more detailed examinations were carried out, and resistance reduction effect by SDX ® in lithium ion battery (LIB) was tried to be clarified.

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Akifumi TAKEDA-ーーーー ＊ 1Haruyuki YAMAMOTO-ーー ＊ 2 This paper presents the results of pile construction work for two steelframe buildings. These buildings incorporate a method proposed by the authors in which the bottom end of a steel column is directly connected to the top end of a precast concrete pile. This method, which was developed for the construction of low-rise, long-span, steel-frame buildings, obviates the need for pile caps and underground beams. This method, however, requires greater accuracy in pile construction than is required with conventional construction methods. Hence, a stringent construction control value was specified for the work, and the outcome satisfied this value. This paper presents the results of pile construction work for two steel-frame buildings. These buildings incorporate a method proposed by the authors in which the bottom end of a steel column is directly connected to the top end of a precast concrete pile. This method, which was developed for the construction of low-rise, long-span, steel-frame buildings, obviates the need for pile caps and underground beams. This method, however, requires greater accuracy in pile construction than is required with conventional construction methods. Hence, a stringent construction control value was specified for the work, and the outcome satisfied this value.

1. Introduction  Practical uses of lithium-ion batteries are rapidly growing especially in large batteries for electric vehicles (EV), energy storage systems (ESS) and so on, but improvements of their characteristics still are strongly demanded.  Large improvements of battery characteristics of LFP (LiFePO4) and NMC (LiNi1/3 Mn1/3 Co1/3 O2) as cathode active material, by using ‘SDXTM’ which is a conducting carbon coated aluminum current collector, have been reported [1,2].  The control of internal resistance of lithium ion batteries by the clarification of mechanism of internal resistance is one of the biggest key items to improve them. So the mechanisms of interface resistance between aluminum current collector and cathode active material layer have been investigated and discussed [3].  In the battery which used LFP as cathode active material, recently the quantitative investigation of contribution to electronic resistance reduction of SDXTMand conducting additives was provided by the result of measurement using ELECTRODE RESISTANCE METER (Under development by HIOKI E.E. CORPORATION) which could divide electrode resistance into material resistance and interface resistance (Fig.1). The interface resistance of the cathde with aluminum current collectors was higher than the material resistance of that by almost one order of magnitude. The interface resistance of the cathode with SDXTMwas lower than that with aluminum current collectors by almost one order of magnitude. Because the interface resistance was reduced by SDXTM, it was reported that conducting additives were able to be reduced much in cathode [4]. In this paper, more detailed examination will be carried out, and the effect of SDXTMin lithium ion battery will be tried to be clarified. 2. Experiment  The preparation of electrode slurry was carried out by dispersing LFP as cathode active material, conducting additives and polyvinylidene difluoride (PVdF) into N-methylpyrrolidone (NMP). Cathode electrodes were prepared by coating the slurry onto SDXTM or aluminum current collectors in several coating speeds (e.g. 300, 400 or 500mm/min), by drying and by pressing them. Artificial graphite (SCMGTM) was used for anode active material, and similarly anode electrodes were prepared by coating its slurry (aqueous solution) onto copper current collectors, by drying and by pressing them. By laminating one sheet of anode and one sheet of cathode, pouch type cell was assembled. 3. Results and discussion  The material resistance and the interface resistance of the cathode were measured by ELECTRODE RESISTANCE METER (Fig.2). In each coating speed, the interface resistance of the cathode with aluminum current collectors was higher than the material resistance of that. The interface resistance of the cathode with SDXTM was lower than that with aluminum current collectors, and it was almost same as the material resistance of the cathode with SDXTM. The interface resistance of the cathode with aluminum current collectors increased when the coating speed increased, but the interface resistance of the cathode with SDXTMwas constant without depending on coating speed. Cell DCRs were measured (Fig.3). The cell DCR with aluminum current collectors increased when the coating speed increased, but the cell DCR with SDXTMwas constant without depending on coating speed. It was confirmed that the cell DCR with aluminum current collector showed similar behavior to the interface resistance of the cathode with aluminum current collector. The visualization results of a dispersion state of conducting additive in an electrode will be presented. References 1. M. Ohmori et al., Electrochemistry, 78, 308, (2011) 2. M. Ohmori et al., Electrochemistry, 79, 165, (2012) 3. M. Ohmori et al., Prime2012 4. A. Takeda, H. Yokouchi, H. Tomozawa, Electrochemistry, 2C25, (2015) Figure 1

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