Engineering Commons^™

High Performance Low Temperature Solid Oxide Fuel Cells With Novel Electrode Architecture, Yu Chen, Qian Liu, Zhibin Yang, Fanglin Chen, Minfang Han

Faculty Publications

In this study, we have fabricated high performance low temperature solid oxide fuel cells (LT-SOFCs) with both acicular anodes and cathodes with thin Gd-doped ceria (GDC) electrolyte film. The acicular Ni-Gd_0.1Ce_0.9O_2−δ (Ni-GDC) anode was prepared using freeze drying tape casting, while the hierarchically porous cathode with nano-size Sm_0.5Sr_0.5CoO₃ (SSC) particles covering an acicular GDC skeleton was prepared by a combination of freeze drying tape casting and self-rising approaches. The acicular electrodes with 5–200 μm pores/channels enhance mass transport, while SSC particles of about 50 nm in the cathode promote …

Complex Of Myoglobin With Phenol Bound In A Proximal Cavity, Xiao Huang, Chunxue Wang, Lesa R. Celeste, Leslie L. Lovelace, Shengfang Sun, John H. Dawson, Lukasz Lebioda

Faculty Publications

Sperm whale myoglobin (Mb) has weak dehaloperoxidase activity and catalyzes the peroxidative dehalogenation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloroquinone. Crystals of Mb and of its more active G65T variant were used to study the binding of TCP, 4-iodophenol (4-IP) and phenol. The structures of crystals soaked overnight in a 10 mM solution of phenol revealed that a phenol molecule binds in the proximal cavity, forming a hydrogen bond to the hydroxyl of Tyr146 and hydrophobic contacts which include interactions with C and C of the proximal histidine His93. The phenol position corresponds to the strongest xenon binding site, Xe1. It …

Can Silver Be A Reliable Current Collector For Electrochemical Tests?, Yunhui Gong, Changyong Qin, Kevin Huang

Faculty Publications

The true functionality of a current collector employed in electrochemical cells is to ensure a low- resistance steady electrons flow between the cell and instrumentation without involving in any local electrochemical reactions of the electrode. In this study, we investigated the effect of curing temperature of a common current collector, silver, on the polarization area specific resistance (ASR) of a cathode. The results explicitly showed that at least one order of magnitude lower ASR for a cathode with Ag cured at 800°C than that cured at 650°C of the same cathode configuration. Microscopic analysis of the 800°C-cured cells revealed a …

Atomistic Investigation Of Scratching-Induced Deformation Twinning In Nanocrystalline Cu, Junjie Zhang, Tao Sun, Yoganda Yan, Dong Shen, Xiaodong Li

Faculty Publications

Deformation twinning is an important deformation mode of nanocrystalline metals. In current study, we investigate the scratching-induced deformation twinning in nanocrystallineCu by means of molecular dynamics simulations. The tribological behavior, the deformation mechanisms, the formation mechanism of deformation twins, and the grain size dependence of the propensity of deformation twinning are elucidated. Simulation results demonstrate that deformation twinning plays an important role in the plastic deformation of nanocrystallineCu under nanoscratching, in addition to dislocation activity and grain boundary-associated mechanism. The nucleation of initial twinning partial dislocations originates from the dissociation of lattice partial dislocations that emit from grain boundary triple …

Wireless Networks-On-Chips: Architecture, Wireless Channel, And Devices, David W. Matolak, Avinash Kodi, Savas Kaya, Dominic Ditomaso, Soumyasanta Laha, William Rayess

Faculty Publications

Wireless networks-on-chips (WINoCs) hold substantial promise for enhancing multicore integrated circuit performance, by augmenting conventional wired interconnects. As the number of cores per IC grows, intercore communication requirements will also grow, and WINoCs can be used to both save power and reduce latency. In this article, we briefly describe some of the key challenges with WINoC implementation, and also describe our example design, iWISE, which is a scalable wireless interconnect design. We show that the integration of wireless interconnects with wired interconnects in NoCs can reduce overall network power by 34 percent while achieving a speedup of 2.54 on real …

Enhanced Methanol Oxidation And Co Tolerance Using Ceo2-Added Eggshell Membrane-Templated Pd Network Electrocatalyst, Qunwei Tang, Zhengping Mao, Shuguo Ma, Kevin Huang

Faculty Publications

Macroporous Pd and CeO₂-added Pd network catalysts have been synthesized using eggshell membrane (ESM) as a template for enhanced methanol oxidation and CO tolerance. The microstructural characterization revealed a hierarchically ordered macroporous network of Pd reproducing the fibrous structure of ESM for a Pd-only catalyst, and a flower-like CeO₂-decorated Pd morphological architecture for the CeO₂-added Pd catalyst synthesized by a precipitation method. XRD patterns indicated Pd and CeO₂ phases with good crystallinity. The cyclic voltammetry studies showed an enhanced electrocatalytic activity for methanol oxidation in acidic aqueous medium. Because of the preferential formation …

Energy Storage Characteristics Of A New Rechargeable Solid Oxide Iron-Air Battery, Xuan Zhao, Nansheng Xu, Xue Li, Yunhui Gong, Kevin Huang

Faculty Publications

Cost effective and large scale energy storage is critical to renewable energy integration and smart-grid energy infrastructure. Rechargeable batteries have great potential to become a class of cost effective technology suited for large scale energy storage. In this paper, we report the energy storage characteristics of a newly developed rechargeable solid oxide iron–air battery. Investigations of the battery’s performance under various current densities and cycle durations show that iron utilization plays a determining role in storage capacity and round-trip efficiency. Further studies of the battery's cycle life reveal a unique charge-cycle originated degradation mechanism that can be interpreted by a …

H3Po4-Imbibed Three-Dimensional Polyacrylamide/Polyacrylamide Hydrogel As A High-Temperature Proton Exchange Membrane With Excellent Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang

Faculty Publications

We herein report the use of polyacrylamide/polyacrylamide interpenetrating polymer network (PAM/PAM IPN) hydrogel as a matrix to imbibe proton conducting H₃PO₄, forming a robust proton exchange membrane (PEM) suitable for high-temperature PEM fuel cells by combining excellent acid retention, simple synthesis, and low cost. Its extraordinary ability to absorb large quantity of aqueous solution is fully utilized to achieve high H₃PO₄ loading, showing a proton conductivity of 0.0833 S cm−1 at 183 °C in dry air. The synthesized membrane also shows excellent acid retention even under mechanical load and high humidity. These profound …

Highly Sensitive X-Ray Detectors In The Low-Energy Range On N-Type 4h-Sic Epitaxial Layers, K. C. Mandal, P. G. Muzykov, J. R. Terry

Faculty Publications

No abstract provided.

Solid Oxide Fuel Cells With Both High Voltage And Power Output By Utilizing Beneficial Interfacial Reaction, Chao Su, Zongping Shao, Ye Lin, Yuzhou Wu, Huanting Wang

Faculty Publications

An intriguing cell concept by applying proton-conducting oxide as the ionic conducting phase in the anode and taking advantage of beneficial interfacial reaction between anode and electrolyte is proposed to successfully achieve both high open circuit voltage (OCV) and power output for SOFCs with thin-film samarium doped ceria (SDC) electrolyte at temperatures higher than 600 °C. The fuel cells were fabricated by conventional route without introducing an additional processing step. A very thin and dense interfacial layer (2–3 μm) with compositional gradient was created by in situ reaction between anode and electrolyte although the anode substrate had high surface roughness …

Characterization Of Ba1-X-YCaXSrYTio3 Perovskites As Pb-Free Dielectric Materials, Lingling Zhang, Siwei Wang, Xusheng Wang, Kevin Huang

Faculty Publications

Use of lead-containing piezoelectric components in electrical and electronic devices has been banned on the EU market since July 1st, 2006. Development of lead-free high performance piezoelectric materials to meet the strong market demand is therefore imperative. In this paper, we report a systematic study on the structural, dielectric and ferroelectric properties of one class of lead-free piezoelectric materials, Ba_1-x-yCa_xSr_yTiO₃ (x = 0-0.4, and y = 0-0.2) ceramics, using techniques such as XRD, SEM, impedance analyzer, and ferroelectric analyzer. It is found that with increasing Sr concentration in Ba …

Order-Disorder Transition Of Aragonite Nanoparticles In Nacre, Zaiwang Huang, Xiaodong Li

Faculty Publications

Understanding nacre’s bottom-up biomineralization mechanism, particularly, how individual aragonite platelets are formed, has long remained elusive due to its crystallographic peculiarity and structural complexity. Here we report that crystallographic order-disorder transition can be triggered within individual aragonite platelets in pristine nacre by means of heat treatment and/or inelastic deformation, offering a unique opportunity to discriminate mysterious aragonite nanoparticles in transmission electron microscopy. Our findings unambiguously uncover why aragonite nanoparticles in pristine nacre have long been inaccessible under TEM observation, which is attributed to the monocrystal-polycrystal duality of the aragonite platelet. The underlying physical mechanism for why an individual aragonite platelet …

High Co2 Permeation Flux Enabled By Highly Interconnected Three-Dimensional Ionic Channels In Selective Co2 Separation Membranes, Lingling Zhang, Nansheng Xu, Xue Li, Siwei Wang, Kevin Huang, William H. Harris, Wilson K. S. Chiu

Faculty Publications

Abatement of CO₂ emissions from existing fossil-fueled power plants is currently the sole near-term solution to stabilize CO₂ concentration in the atmosphere. Separation and capture of CO₂from process streams of these power plants is the first step toward this effort. In this paper, we report a high flux membrane consisting of highly and efficiently interconnected three-dimensional ionic channels prepared from a combined “co-precipitation” and “sacrificial-template” synthesis. The membranes exhibit remarkable CO₂ permeation characteristic, achieving a CO₂ flux density two orders of magnitude higher than other similar systems reported in the literature. The experimental results …

Multiple Structure Alignment With Mstali, Paul Shealy, Homayoun Valafar

Faculty Publications

Background

Multiple structure alignments have received increasing attention in recent years as an alternative to multiple sequence alignments. Although multiple structure alignment algorithms can potentially be applied to a number of problems, they have primarily been used for protein core identification. A method that is capable of solving a variety of problems using structure comparison is still absent. Here we introduce a program msTALI for aligning multiple protein structures. Our algorithm uses several informative features to guide its alignments: torsion angles, backbone C^α atom positions, secondary structure, residue type, surface accessibility, and properties of nearby atoms. The algorithm allows …

State Of Charge And Loss Of Active Material Estimation Of A Lithium Ion Cell Under Low Earth Orbit Condition Using Kalman Filtering Approaches, Saeed Khaleghi Rahimian, Sean Rayman, Ralph E. White

Faculty Publications

The state of charge (SOC) and the loss of active material of the electrodes of a Li ion cell under Low Earth Orbit condition (LEO) have been estimated using Kalman filtering methods, by means of the physics-based single particle (SP) model. Zero mean Gaussian noise was added to the charge-discharge curves obtained by the SP model to generate synthetic data. Afterwards, nonlinear Filtering approaches including Extended Kalman Filtering (EKF) and Unscented Kalman Filtering (UKF) were applied to predict the true SOC and the electrodes’ degradation, by minimizing the measurement residuals between the model prediction and the synthetic data. The results …

Sr2Fe1.5Mo0.5O6-Δ – Sm0.2Ce0.8O1.9 Composite Anodes For Intermediate-Temperature Solid Oxide Fuel Cells, Beibei He, Ling Zhao, Shuxiang Song, Tong Liu, Fanglin Chen, Changrong Xia

Faculty Publications

Sr₂Fe_1.5Mo_0.5O_6−δ (SFM) perovskite is carefully investigated as an anode material for solid oxide fuel cells with LaGaO₃-based electrolytes. Its electronic conductivity under anodic atmosphere is measured with four-probe method while its ionic conductivity is determined with oxygen permeation measurement. Samaria doped ceria (SDC) is incorporated into SFM electrode to improve the anodic performance. A strong relation is observed between SDC addition and polarization losses, suggesting that the internal SFM-SDC contacts are active for H₂ oxidation. The best electrode performance is achieved for the composite with 30 wt% SDC addition, resulting …

A Ceramic-Anode Supported Low Temperature Solid Oxide Fuel Cell, Hanping Ding, Junjie Ge, Xingjian Xue

Faculty Publications

We report the fabrication and evaluation of a ceramic-anode supported button cell LSCM-SDC/SDC/PBSC (thickness 400 μm/20 μm/20 μm). The anode/electrolyte assembly LSCM-SDC/SDC was co-fired at low temperature of 1250°C, where a slight amount of CuO was mixed with LSCM. The CuO (20.3 wt%) were impregnated into the porous substrate to enhance current collecting effect. The cell exhibited power density of 596 mWcm−2 and 381 mWcm−2 at 700°C with wet hydrogen and methane as the fuel respectively, where the silver paste was used as current collectors, the highest performance up to date for the cells with metal oxide anodes at this …

A New Approach For The Preparation Of Variable Valence Rare Earth Alloys From Nano Rare Earth Oxides At A Low Temperature In Molten Salt, Milin Zhang, Yongde Yan, Wei Han, Xing Li, Zhiyao Hou, Yang Tian, Ke Ye, Lihong Bao, Xiaodong Li, Zhijian Zhang

Faculty Publications

The solubility of RE₂O₃ (RE = Eu, Sm, and Yb) with variable valence in molten salts is extremely low. It is impossible to directly obtain variable valence metals or alloys from RE₂O₃ using electrolysis in molten salts. We describe a new approach for the preparation of variable valence rare earth alloys from nano rare earth oxide. The excellent dispersion of nano–Eu₂O₃ in LiCl–KCl melts was clearly observed using a luminescent feature of Eu³⁺ as a probe. The ratio of solubility of nano-Sm₂O₃/common Sm₂O_{3 …}

Temperature Dependence Of Current Conduction In Semi-Insulating 4h-Sic Epitaxial Layer, P. G. Muzykov, Ramesh Madhu Krishna, K. C. Mandal

Faculty Publications

No abstract provided.

Conclusion Panel, Allison Marsh

Section 6: Conclusion

No abstract provided.

Usc's Nanocenter, Allison Marsh

Section 5: Imaging at the Nano Scale

No abstract provided.

Fact Or Fiction?, Allison Marsh

Section 5: Imaging at the Nano Scale

No abstract provided.

Nano Imaging, Allison Marsh

Section 5: Imaging at the Nano Scale

No abstract provided.

Choosing An Instrument, Allison Marsh

Section 5: Imaging at the Nano Scale

No abstract provided.

Mapping The Ocean Frontier, Allison Marsh

Section 4: Imaging the Concealed

No abstract provided.

Spotlight On Usc: South Carolina Institute For Anthropology And Archaeology, Allison Marsh

Section 4: Imaging the Concealed

No abstract provided.

Seeing With Sound, Allison Marsh

Section 4: Imaging the Concealed

No abstract provided.

World Ocean Floor, Courtesy Of The Library Of Congress, Allison Marsh

Section 4: Imaging the Concealed

No abstract provided.

Marie Tharp At Her Drafting Table, Courtesy Of The Lamont-Doherty Earth Observatory, Earth Institute, Columbia University, Allison Marsh

Section 4: Imaging the Concealed

No abstract provided.

Why Do We Collect?, Allison Marsh

Section 2: Imaging the Microscopic

No abstract provided.