Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 18 of 18

Full-Text Articles in Entire DC Network

Promoting Electrocatalytic Activity Of A Composite Sofc Cathode La0.8Sr0.2Mno3+Δ/Ce0.8Gd0.2O2-Δ With Molten Carbonates, Yunhui Gong, Xue Li, Lingling Zhang, Whitney Tharp, Changyong Qin, Kevin Huang Dec 2013

Promoting Electrocatalytic Activity Of A Composite Sofc Cathode La0.8Sr0.2Mno3+Δ/Ce0.8Gd0.2O2-Δ With Molten Carbonates, Yunhui Gong, Xue Li, Lingling Zhang, Whitney Tharp, Changyong Qin, Kevin Huang

Faculty Publications

The effect of molten carbonates (MCs) on polarization resistance (RP), a direct measure of oxygen reduction reaction (ORR) activity, of a composite La0.8Sr0.2MnO3+δ/Ce0.8Gd0.2O2-δ (LSM/GDC) solid oxide fuel cell (SOFC) cathode has been systematically investigated in this study over a temperature range of 550–650°C and partial pressure of oxygen (pO2) span of 10−3 ∼ 1 atm. It is shown that the LSM/GDC cathode, either in the pristine or MC-modified states, can be generally modeled by two consecutive parallel circuits consisting of a resistance and a …


Enhanced Reversibility And Durability Of A Solid Oxide Fe–Air Redox Battery By Carbothermic Reaction Derived Energy Storage Materials, Xuan Zhao, Xue Li, Yunhui Gong, Kevin Huang Oct 2013

Enhanced Reversibility And Durability Of A Solid Oxide Fe–Air Redox Battery By Carbothermic Reaction Derived Energy Storage Materials, Xuan Zhao, Xue Li, Yunhui Gong, Kevin Huang

Faculty Publications

The recently developed solid oxide metal–air redox battery is a new technology capable of high-rate chemistry. Here we report that the performance, reversibility and stability of a solid oxide iron–air redox battery can be significantly improved by nanostructuring energy storage materials from a carbothermic reaction.


A New Solid Oxide Molybdenum–Air Redox Battery, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang Oct 2013

A New Solid Oxide Molybdenum–Air Redox Battery, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

A new type of rechargeable molybdenum–air battery based on the technologies of reversible solid oxide fuel cells and chemical looping is reported in this study. The reversible solid oxide fuel cell serves as the electrical unit to realize the charging and discharging cycles while a pair of Mo/MoO2 redox couple integrated with the reversible solid oxide fuel cell stores electrical energy via an H2–H2O oxygen shuttle. The specific charge of the new battery reaches 1117 A h per kg-Mo at 550°C, which is 45% higher than the non-rechargeable Mo–air battery. The corresponding discharge specific energy is 974 W h per …


Enhanced Reducibility And Conductivity Of Na/K-Doped Srti0.8Nb0.2O3, Guoliang Xiao, Sirikanda Nuansaeng, Lei Zhang, Suwit Suthirakun, Andreas Heyden, Hans-Conrad Zur Loye, Fanglin Chen Sep 2013

Enhanced Reducibility And Conductivity Of Na/K-Doped Srti0.8Nb0.2O3, Guoliang Xiao, Sirikanda Nuansaeng, Lei Zhang, Suwit Suthirakun, Andreas Heyden, Hans-Conrad Zur Loye, Fanglin Chen

Faculty Publications

Donor and acceptor co-doped SrTiO3 materials have shown interesting features in their conductivity and reducibility. In this work, 10 mol% Na+ or K+ as acceptor dopants have been introduced into the A-site of donor-doped strontium titanate, SrTi0.8Nb0.2O3, and the doping impact on their properties has been studied. By doping with Na or K, the sinterability of SrTi0.8Nb0.2O3 in reducing atmospheres has been improved. Na0.1Sr0.9Ti0.8Nb0.2O3 and K0.1Sr0.9Ti0.8Nb0.2O3 show metallic …


Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang Aug 2013

Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

The recently developed rechargeable solid oxide metal-air redox battery has shown a great potential for applications in mid- to large-scale stationary energy storage. Cyclic durability is one of the most important requirements for stationary energy storage. In this study, we report the cyclic durability of a solid oxide Fe-air redox battery operated at 650°C. The battery was continuously cycled 100 times under a current density of 50 mA/cm2 with rather flat performance, producing an average specific energy of 760 Wh/kg-Fe at a round-trip efficiency of 55.5%. The post-test examination indicated that the performance losses could arise from the fuel-electrode …


Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang Aug 2013

Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

The recently developed rechargeable solid oxide metal-air redox battery has shown a great potential for applications in mid- to large-scale stationary energy storage. Cyclic durability is one of the most important requirements for stationary energy storage. In this study, we report the cyclic durability of a solid oxide Fe-air redox battery operated at 650◦C. The battery was continuously cycled 100 times under a current density of 50 mA/cm2 with rather flat performance, producing an average specific energy of 760 Wh/kg-Fe at a round-trip efficiency of 55.5%. The post-test examination indicated that the performance losses could arise from the fuel-electrode of …


Unveiling The Roles Of Binder In The Mechanical Integrity Of Electrodes For Lithium-Ion Batteries, Jianchao Chen, Jianyong Liu, Yue Qi, Tao Sun, Xiaodong Li Jul 2013

Unveiling The Roles Of Binder In The Mechanical Integrity Of Electrodes For Lithium-Ion Batteries, Jianchao Chen, Jianyong Liu, Yue Qi, Tao Sun, Xiaodong Li

Faculty Publications

In lithium-ion secondary batteries research, binders have received the least attention, although the electrochemical performance of Li-ion batteries such as specific capacity and cycle life cannot be achieved if the adhesion strengths between electrode particles and between electrode films and current collectors are insufficient to endure charge-discharge cycling. In this paper, the roles of binders in the mechanical integrity of electrodes for lithium-ion batteries were studied by coupled microscratch and digital image correlation (DIC) techniques. A microscratch based composite model was developed to decouple the carbon particle/particle cohesion strength from the electrode-film/copper-current-collector adhesion strength. The dependences of microscratch coefficient of …


First Spectroscopic Identification Of Pyrocarbonate For High Co2 Flux Membranes Containing Highly Interconnected Three Dimensional Ionic Channels, Lingling Zhang, Xinyu Huang, Changyong Qin, Kyle Brinkman, Yunhui Gong, Siwei Wang, Kevin Huang Jun 2013

First Spectroscopic Identification Of Pyrocarbonate For High Co2 Flux Membranes Containing Highly Interconnected Three Dimensional Ionic Channels, Lingling Zhang, Xinyu Huang, Changyong Qin, Kyle Brinkman, Yunhui Gong, Siwei Wang, Kevin Huang

Faculty Publications

Identification of the existence of pyrocarbonate ion C2O52− in molten carbonates exposed to a CO2 atmosphere provides key support for a newly established bi-ionic transport model that explains the mechanisms of high CO2 permeation flux observed in mixed oxide-ion andcarbonate-ion conducting (MOCC) membranes containing highly interconnected three dimensional ionic channels. Here we report the first Raman spectroscopic evidence of C2O52− as an active species involved in the CO2-transport process of MOCC membranes exposed to a CO2atmosphere. The two new broad peaks centered at 1317 cm−1 …


Performance Of Solid Oxide Iron-Air Battery Operated At 550°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang May 2013

Performance Of Solid Oxide Iron-Air Battery Operated At 550°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

“Metal-air” batteries have garnered much attention in recent years due to their high intrinsic specific energy and use of inexhaustible and storage-free oxygen source -air- for the “metal-oxygen” reaction. In this study, we report theperformance of a new type of all solid-state “iron-air” battery operated at 550°C. The results show that CeO2 nanoparticles incorporated into the Fe-Fe3O4 redox-couple can improve the specific energy (Wh/kg) and round trip efficiency by 15% and 29%, respectively, over the baseline Fe-Fe3O4 battery. Use of supported Fe-Fe3O4 nanoparticles as the redox couple can increase the …


Micro Modeling Study Of Cathode/Electrolyte Interfacial Stresses For Solid Oxide Fuel Cells, Xinfang Jin, Xingjian Xue May 2013

Micro Modeling Study Of Cathode/Electrolyte Interfacial Stresses For Solid Oxide Fuel Cells, Xinfang Jin, Xingjian Xue

Faculty Publications

Delamination of the cathode/electrolyte interface is an important degradation phenomenon in solid oxide fuel cells (SOFCs). While the thermal stress has been widely recognized as one of the major reasons for such delamination failures, the role of chemical stress does not receive too much attention. In this paper, a micro-model is developed to study the cathode/electrolyte interfacial stresses, coupling oxygen ion transport process with structural mechanics. Results indicate that the distributions of chemical stress are very complicated at the cathode/electrolyte interface and show different patterns from those of thermal stress. The maximum principal stresses take place at the cathode/electrolyte interface …


A High Energy Density All Solid-State Tungsten-Air Battery, Xuan Zhao, Xue Li, Yunhui Gong, Nansheng Xu, Kevin Gregory Romito, Kevin Huang Apr 2013

A High Energy Density All Solid-State Tungsten-Air Battery, Xuan Zhao, Xue Li, Yunhui Gong, Nansheng Xu, Kevin Gregory Romito, Kevin Huang

Faculty Publications

An all solid-state tungsten–air battery using solid oxide–ion electrolyte is demonstrated as a new chemistry for advanced energy storage. The unique design of separated energy storage from the electrodes allows for free volume expansion–contraction during electrical cycles and new metal–air chemistry to be explored conveniently.


Enhanced Nucleate Boiling On Horizontal Hydrophobic-Hydrophilic Carbon Nanotube Coatings, Xianming Dai, Xinyu Huang, Fanghao Yang, Xiaodong Li, Joshua Sightler, Yingchao Yang, Chen Li Apr 2013

Enhanced Nucleate Boiling On Horizontal Hydrophobic-Hydrophilic Carbon Nanotube Coatings, Xianming Dai, Xinyu Huang, Fanghao Yang, Xiaodong Li, Joshua Sightler, Yingchao Yang, Chen Li

Faculty Publications

Ideal hydrophobic-hydrophilic composite cavities are highly desired to enhance nucleate boiling. However, it is challenging and costly to fabricate these types of cavities by conventional micro/nano fabrication techniques. In this study, a type of hydrophobic-hydrophilic composite interfaces were synthesized from functionalized multiwall carbon nanotubes by introducing hydrophilic functional groups on the pristine multiwall carbon nanotubes. This type of carbon nanotube enabled hydrophobic-hydrophilic composite interfaces were systematically characterized. Ideal cavities created by the interfaces were experimentally demonstrated to be the primary reason to substantially enhance nucleate boiling


Atomic Layer Deposition On Porous Materials: Problems With Conventional Approaches To Catalyst And Fuel Cell Electrode Preparation, Tzia Ming Onn, Rainer Küngas, Paolo Fornasiero, Kevin Huang, Raymond J. Gorte Mar 2013

Atomic Layer Deposition On Porous Materials: Problems With Conventional Approaches To Catalyst And Fuel Cell Electrode Preparation, Tzia Ming Onn, Rainer Küngas, Paolo Fornasiero, Kevin Huang, Raymond J. Gorte

Faculty Publications

Atomic layer deposition (ALD) offers exciting possibilities for controlling the structure and composition of surfaces on the atomic scale in heterogeneous catalysts and solid oxide fuel cell (SOFC) electrodes. However, while ALD procedures and equipment are well developed for applications involving flat surfaces, the conditions required for ALD in porous materials with a large surface area need to be very different. The materials (e.g., rare earths and other functional oxides) that are of interest for catalytic applications will also be different. For flat surfaces, rapid cycling, enabled by high carrier-gas flow rates, is necessary in order to rapidly grow thicker …


Hydrophobic Hydrogel Caged H3Po4 As A New Class Of High-Temperature Proton Exchange Membranes With Enhanced Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang Jan 2013

Hydrophobic Hydrogel Caged H3Po4 As A New Class Of High-Temperature Proton Exchange Membranes With Enhanced Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang

Faculty Publications

We herein report a new class of high-temperature proton exchange membranes comprised of poly(acrylic acid-graft-hexadecyltrimethylammonium bromide) (PAA-g-CTAB) or poly(acrylic acid)-graft-poly(ethylene glycol) (PAA-g-PEG) hydrophobic hydrogel caged H3PO4. The membranes exhibit reasonable proton conductivity, enhanced H3PO4 retention ability and low solubility in water, making them promising as potential high performance and robust electrolytes for high-temperature proton exchange membrane fuel cells. Although the proton conductivity is still lower than that of H3PO4 doped PBI membranes, the new concept provides a different approach to proton exchange membranes for acid retention.


Wave Propagation In Metamaterial Using Multiscale Resonators By Creating Local Anisotropy, Raiz U. Ahmed, Sourav Banerjee Jan 2013

Wave Propagation In Metamaterial Using Multiscale Resonators By Creating Local Anisotropy, Raiz U. Ahmed, Sourav Banerjee

Faculty Publications

Directional guiding, passing or stopping of elastic waves through engineered materials have many applications to the engineering fields. Recently, such engineered composite materials received great attention by the broader research community. In elastic waves, the longitudinal and transverse motion of material particles are coupled, which exhibits richer physics and demands greater attention than electromagnetic waves and acoustic waves in fluids. Waves in periodic media exhibit the property of Bragg scattering and create frequency band gaps in which the energy propagation is prohibited. However, in addition to the Bragg scattering, it has been found that local resonance of artificially designed resonators …


Molten Carbonates As An Effective Oxygen Reduction Catalyst For 550–650°C Solid Oxide Fuel Cells, Yunhui Gong, Xue Li, Lingling Zhang, Whitney Tharp, Changyong Qin, Kevin Huang Jan 2013

Molten Carbonates As An Effective Oxygen Reduction Catalyst For 550–650°C Solid Oxide Fuel Cells, Yunhui Gong, Xue Li, Lingling Zhang, Whitney Tharp, Changyong Qin, Kevin Huang

Faculty Publications

We report the first study that investigates the use of molten carbonates as an effective catalyst to promote electrochemical oxygen reduction reaction (ORR) at the cathode of intermediate temperature solid oxide fuel cells (IT-SOFCs). A series of binary Li-K carbonate compositions were incorporated into the porous backbones of a commercial cathode assembled in symmetrical impedance cells for electrochemical characterization. Within the temperature range of 550–650◦C, we observed that the polarization and ohmic area-specific resistances of the original sample can be significantly reduced by the introduction of molten carbonates. A new ORR charge-transfer model involving two intermediate species CO5 2− and …


The Effect Of Isostatic Pressing On The Dielectric Properties Of Screen Printed Ba0.5Sr0.5Tio3 Thick Films, Siwei Wang, Lingling Zhang, Jiwei Zhai, Fanglin Chen Jan 2013

The Effect Of Isostatic Pressing On The Dielectric Properties Of Screen Printed Ba0.5Sr0.5Tio3 Thick Films, Siwei Wang, Lingling Zhang, Jiwei Zhai, Fanglin Chen

Faculty Publications

Ba0.5Sr0.5TiO3 thick films with B2O3–Li2O glass sintering aid were prepared by the screen printing method on Al2O3 substrates. A 200 MPa isostatic pressure was applied to the films before sintering. After being sintered at 950C, lower porosity and denser microstructure was obtained compared with the films without isostatic pressing. The dielectric constant and dielectric loss were 238 and 0.0028, respectively. A tunability of 61.7% was obtained for the isostatic pressed films, a 27.8% enhancement compared to unpressurized films. These results suggest that isostatic pressing …


Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang Jan 2013

Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang

Faculty Publications

In this paper, we demonstrate the variation of donut-shaped depletion pattern which influenced by multiple primary aberrations. The simulation is base on a common stimulation emission of depletion (STED) system composed by Gaussian laser and vortex phase plate. The simulation results are helpful guidelines for analyzing the aberration of depletion patterns in real situations.