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排序方式: 共有2892条查询结果,搜索用时 15 毫秒
81.
A. Egetenmeyer I. Radev D. Durneata M. Baumgärtner V. Peinecke H. Natter R. Hempelmann 《International Journal of Hydrogen Energy》2017,42(19):13649-13660
Nanostructured Pt and Pt3Co cathodes for proton exchange membrane fuel cells (PEMFCs) have been prepared by pulse electrodeposition. For high utilization the catalyst nanoparticles are directly deposited on the microporous layer (MPL) of a commercial available gas diffusion layer (GDL). In order to increase the hydrophilic nature of the substrate surface and thus improve drastically the electrodeposition process and the fuel cell performance, prior to electrodeposition, the carbon substrate is submitted to O2/Ar plasma activation. Cathodes with different amounts and distributions of Aquivion ionomer within the cathode catalyst layer (CCL) thickness (“homogeneous”, “gradient” and “anti-gradient”), different catalysts (Pt and Pt3Co) at varied plasma duration and catalyst loading have been prepared. The cathodes are analysed via attenuated total reflection (ATR-IR), goniometer, SEM, 0.5 M H2SO4 half-cell and 25 cm2 H2/Air single PEMFC. The highest single fuel cell performance is obtained for 2 min plasma activated Pt3Co cathode. 相似文献
82.
Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride. The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid, and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride. Pyrolusite is reduced by citric acid during leaching, cobalt intergrown with which is liberated and subsequently chelated by the citric acid. The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated. 相似文献
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鲁中选矿厂钴回收的探讨 总被引:1,自引:0,他引:1
鲁中冶金矿业集团公司所属的港里矿2003年开始首采.随着开采量的不断增加,港里矿矿石成为选厂入选矿的主要来源,钴的赋存状态发生了变化,使钴的回收成为可能.试验表明,采用强磁抛尾-铜、钴混浮-铜、钴分离的流程效果较好. 相似文献
86.
To improve the cycling performance of LiNi0.8Co0.15Al0.05O2 at 55 °C, a thin Ni3(PO4) layer was homogeneously coated onto the cathode particle via simple ball milling. The morphology of the Ni3(PO4)2-coated LiNi0.8Co0.15Al0.05O2 particle was characterized using SEM and TEM analysis, and the coating thickness was found to be approximately 10-20 nm. The Ni3(PO4)2-coated LiNi0.8Co0.15Al0.05O2 cell showed improved lithium intercalation stability and rate capability especially at high C rates. This improved cycling performance was ascribed to the presence of Ni3(PO4)2 on the LiNi0.8Co0.15Al0.05O2 particle, which protected the cathode from chemical attack by HF and thus suppressed an increase in charge transfer resistance. Transmission electron microscopy of extensively cycled particles confirmed that the particle surface of the Ni3(PO4)2-coated LiNi0.8Co0.15Al0.05O2 remained almost undamaged, whereas pristine particles were severely serrated. The stabilization of the host structure by Ni3(PO4)2 coating was also verified using X-ray diffraction. 相似文献
87.
Youmin GuoYunbo Zhou Dengjie ChenHuangang Shi Ran RanZongping Shao 《Journal of power sources》2011,196(13):5511-5519
The effects of the current collection material and method on the performance of SOFCs with Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) cathodes are investigated. Ag paste and LaCoO3 (LC) oxide are studied as current collection materials, and five different current collecting techniques are attempted. Cell performances are evaluated using a current-voltage test and electrochemical impedance spectra (EIS) based on two types of anode-supported fuel cells, i.e., NiO + SDC|SDC|BSCF and NiO + YSZ|YSZ|SDC|BSCF. The cell with diluted Ag paste as the current collector exhibits the highest peak power density, nearly 16 times that of a similar cell without current collector. The electrochemical characteristics of the BSCF cathode with different current collectors are further determined by EIS at 600 °C using symmetrical cells. The cell with diluted Ag paste as the current collector displays the lowest ohmic resistance (1.4 Ω cm2) and polarization resistance (0.1 Ω cm2). Meanwhile, the surface conductivities of various current collectors are measured by a four-probe DC conductivity technique. The surface conductivity of diluted Ag paste is 2-3 orders of magnitude higher than that of LC or BSCF. The outstanding surface conductivity of silver may reduce the contact resistance at the current collector/electrode interface and, thus, contributes to better electrode performance. 相似文献
88.
Shoichiro Watanabe Masahiro KinoshitaKensuke Nakura 《Journal of power sources》2011,196(16):6906-6910
Nickel-based oxide cathode material taking out from lithium-ion cell after storage for 2 years at 45 °C is analyzed by electron energy-loss spectroscopy in a scanning transmission electron microscope (STEM-EELS) and the result of STEM-EELS is compared with cobalt-based oxide cathode material which is treated as same manor as nickel-based oxide cathode material. The Ni-L2,3 energy-loss near-edge structure (ELNES) spectra of nickel-based oxide cathode material show peak positions similar to original material before storage. This result indicates that nickel-based oxide material has no significant change in the surface structure. On the other hand, a remarkable shift to low energy is observed in the Co-L2,3 ELNES spectra of the cobalt-based oxide cathode material after storage. The cycle test at 60 °C under the conditions of aggressive driving cycle (US06) mode for the nickel-based oxide cathode/graphite cell is also carried out. It is clear that cycle performance of the nickel-based oxide cathode/graphite cell is dependent on the depth of discharge (DOD). 相似文献
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Nasser A.M. Barakat Mohammad A. Abdelkareem Gwisu Shin Hak Yong Kim 《International Journal of Hydrogen Energy》2013
High contact resistance and corrosion are the main dilemma facing wide application of the metallic bipolar plates. In this study, deposition of thin film from Pd-decorated Co nanofibers on a silicon substrate is introduced as a novel strategy to produce functionalized metallic bipolar plate. The novel active metallic bipolar plate can be prepared by using simple, low cost, high yield and effective technique; electrospinning. The bimetallic nanofibrous film chemically bonds with the silicon substrate due to formation of silicon carbide which leads to merge the deeper nanofibers with the silicon surface. Accordingly, high current density (100 mA cm−1) was obtained when the introduced covered silicon wafer was utilized as anode catalyst for formic acid electrooxidation. Because the bimetallic nanofibers are sheathed in a thin graphite shell, the introduced active bipolar plate reveals very good stability. Overall, the introduced study is opening a new avenue to prepare new class of functionalized metallic bipolar plates. 相似文献