Rechargeable Zn-air Energy Storage Cells Providing High Power Density (original) (raw)
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Applied Chemistry for Engineering, 2012
Zn-Air energy storage cell is an attractive type of batteries due to its theoretical gravimetric energy density, cost-effective structure and environmental-friendly characteristics. The chargeability is the most critical in various industrial applications such as smart portable device, electric vehicle, and power storage system. Thus, it is necessary to reduce large overpotential of oxygen reduction/evolution reaction, the irreversibility of Zn anode, and carbonation in alkaline electrolyte. In this review, we try to introduce recent studies and developments of bi-functional air cathode, enhanced charge efficiency via modification of Zn anode structure, and blocking side reactions applying hybrid organic-aqueous electrolyte for high power density rechargeable Zn-Air energy storage cells.
Effect of Zn/NaCl ratios on the charge/discharge performance in Na-ZnCl2 battery
Han'gug gyeoljeong seongjang haghoeji, 2015
Na-ZnCl 2 battery, which operates as the same mechanism of Na-NiCl 2 battery using solid-electrolyte, is able to reduce its material cost by 40 % comparing to the Na-NiCl 2 battery. It has been known that the Na-ZnCl 2 battery produces Na 2 ZnCl 4 as an intermediate phase during charge/discharge process. Therefore, the redox process is divided into four steps having the voltage range of 1.92~2.13 V. However, effects of the critical factors such as the composition of cathode materials, depth of charge and discharge, and additives have not been reported yet. We examined the effect of the Zn/NaCl ratios and revealed that its optimum ratio was in the range of 1.3~1.7.
A Study of the Development of a High-Strength Al-Zn Based Alloy for Die Casting I
Korean Journal of Metals and Materials, 2010
Al-Zn based alloys are the most common types of wrought Al alloys. Although Al-Zn alloys have high strength, they cannot be applied to a conventional casting process. In this study, Al-Zn-based alloys applicable to a die casting process were developed successfully. The developed Al-45 wt% Zn-based alloys showed a fine equiaxed grain structure and high strength. A fine equiaxed grain having an average size of 25 µm was obtained by the die casting process. The UTS and elongation of the new alloy are 475 MPa and 3.5%, respectively. In addition, we elucidate the effect of a Zn addition on variations in different mechanical properties and the microstructure characteristics of (Al96.3-xZnxCu3Si0.4Fe0.3) x=20, 30, 40, and 45 wt% alloys fabricated by a die casting process.
KEPCO Journal on electric power and energy, 2015
Large scale superconducting magnetic energy storage (SMES) system requires very high magnetic energy density in its superconducting coils to enhance the energy capacity and efficiency of the system. The recent high temperature superconducting (HTS) conductors, so called 2G conductors, show very good performance under very high magnetic field so that they seem to be perfect materials for the large scale SMES coils. A general shape of the coil system with the 2G HTS conductor has been a toroid, because the magnetic field applied perpendicularly to the surface of the 2G HTS conductor could be minimized in this shape of coil. However, a toroid coil requires a 3-dimensional computation to acquire the characteristics of its critical current densitymagnetic field relations which needs very complicated numerical calculation, very high computer specification, and long calculation time. In this paper, we suggested an analytic and statistical calculation method to acquire the maximum magnetic flux density applied perpendicularly to the surface of the 2G HTS conductor and the stored energy in the toroid coil system. Although the result with this method includes some errors but we could reduce these errors within 5 percent to get a reasonable estimation of the important parameters for design process of the HTS toroid coil system. As a result, the calculation time by the suggested method could be reduced to 0.1 percent of that by the 3-dimensional numerical calculation.
Annealing Characteristics of Electrodeposited Cu(In,Ga)Se2 Photovoltaic Thin Films
Korean Journal of Materials Research, 2010
Cu(In,Ga)Se 2 (CIGS) photovoltaic thin films were electrodeposited on Mo/glass substrates with an aqueous solution containing 2 mM CuCl 2 , 8 mM InCl 3 , 20 mM GaCl 3 and 8 mM H 2 SeO 3 at the electrodeposition potential of −0.6 to −1.0 V(SCE) and pH of 1.8. The best chemical composition of Cu 1.05 In 0.8 Ga 0.13 Se 2 was found to be achieved at −0.7 V(SCE). The precursor Cu-In-Ga-Se films were annealed for crystallization to chalcopyrite structure at temperatures of 100-500 o C under Ar gas atmosphere. The chemical compositions, microstructures, surface morphologies, and crystallographic structures of the annealed films were analyzed by EPMA, FE-SEM, AFM, and XRD, respectively. The precursor Cu-In-Ga-Se grains were grown sparsely on the Mo-back contact and also had very rough surfaces. However, after annealing treatment beginning at 200 o C, the empty spaces between grains were removed and the grains showed well developed columnar shapes with smooth surfaces. The precursor Cu-In-Ga-Se films were also annealed at the temperature of 500 o C for 60 min under Se gas atmosphere to suppress the Se volatilization. The Se amount on the CIGS film after selenization annealing increased above the Se amount of the electrodeposited state and the MoSe 2 phase occurred, resulting from the diffusion of Se through the CIGS film and interaction with Mo back electrode. However, the selenization-annealed films showed higher crystallinity values than did the films annealed under Ar atmosphere with a chemical composition closer to that of the electrodeposited state.
세라믹칩 전기적 성능검사 시스템을 위한 고속구동 액튜에이터 개발
Journal of the Korea Academia-Industrial cooperation Society, 2011
The core of IT products, electronic components, especially the MLCC, chip inductors, chip Varistors and so on. In order to test the electrical characteristics of the chip using the Reno-pin contact test method has been used. In current chips, mass production of semiconductor manufacturing processes, high-speed production test for the chip speed up, precision is required. But Vibration displacement is a very short, so in order to overcome these shortcomings, the displacement amplification to design the structure has been actively studied. In this paper, a building structure with a flexible hinge was designed amplification instrument, semiconductor chip industry in the performance test and inspection equipment to measure the electrical characteristics of high speed linear actuators Reno-Pin using system was developed.
임베디드 소프트웨어의 소모전력 분석을 위한 에너지 컴포넌트 라이브러리
The KIPS Transactions:PartD, 2009
Along with the complexity and size growth of embedded software, it is critical to meet the nonfunctional requirements such as power consumption as well as functional requirements such as correctness. This paper, apart from the existing studies of source code-based power analysis, proposes an approach of model-based power analysis using UML 2.0. Specially, we focus on the development of energy library to analyze the power consumption of embedded software. Our energy library supports model-based power analysis, and also supports the easy adaption for the change of embedded application.
Optimal Placement of Distributed Generation Units Considering Voltage Sags
The Transactions of The Korean Institute of Electrical Engineers, 2013
This paper presents a method for determining the optimal placement of distributed generation units considering voltage sags. In general, the existing methods for distributed generation placement do not consider power quality problems such as voltage sags. In this paper, a novel method based on both genetic algorithm and voltage sag assessment is proposed for determining the placement of distributed generation unit. In the proposed method, the optimal placement is determined to minimize voltage sag effects and system losses.