Enhance Diamond Coating Adhesion By Oriented Interlayer Microcracking,
2015
University of South Carolina - Columbia
Enhance Diamond Coating Adhesion By Oriented Interlayer Microcracking, Habio Guo, Xingcheng Xiao, Yue Qi, Zhi-Hui Xu, Xiaodong Li
Xiaodong Li
In this paper, we report a microcrack toughening mechanism for enhancing the adhesion of diamondcoating. The oriented microcracks were formed within the TiC interlayer to dissipate strain energy and accommodate deformation via the crack opening-closing mechanism, thus enhancing the coating/substrate interfacial toughness. The delamination of diamondcoating was effectively prevented when the parallel microcracks were confined within the interlayer and arrested at interfaces of coating/interlayer/substrate. Density functional theory calculations revealed that the highly anisotropicfracture strength of the TiC phase energetically favors crack initiation and propagation along (100) planes only, which are 54.7° away from the interface. These microcracks are constrained inside …
Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings,
2015
University of South Carolina - Columbia
Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li
Xiaodong Li
Nano-/micronecklaces with SiO2 beads in boron strings were synthesized by simply sublimating the desired powders in a sealed quartz tube at high temperature. The boron strings have a rectangular cross section with width varying from 80to1000nm while the SiO2 beads bear either spindle or spherical shape with a size ranging from 100nmto5μm. The spacing between the SiO2 beads is uniform in each boron string. Both the boron strings and the SiO2 beads are amorphous and free of defects. The supersaturated vapors of silicon and oxygen induced the SiO2 bead formation.
In Situ Synthesis Of Ultrafine Ss-Mno2/Polypyrrole Nanorod Composites For High-Performance Supercapacitors,
2015
University of South Carolina - Columbia
In Situ Synthesis Of Ultrafine Ss-Mno2/Polypyrrole Nanorod Composites For High-Performance Supercapacitors, Jianfeng Zang, Xiaodong Li
Xiaodong Li
We report a remarkable observation that is at odds with the established notion that β-MnO2 was regarded as an undesirable candidate for supercapacitor applications. The specific capacitance of β-MnO2 can reach as high as 294 F g−1, which is comparable to the best crystallographic structure, like α-MnO2. The key is to substantially decrease the size of β-MnO2 powders to ultra small regime. We demonstrate a facile, simple, and effective approach to synthesizing ultrafine (<10 nm in diameter) β-MnO2/polypyrrole nanorod composite powders for high-performance supercapacitor electrodes. Our observation may encourage a revisit of the other good or even bad candidate …
Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3.,
2015
University of South Carolina - Columbia
Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater
Xiaodong Li
A thermodynamic model of cavitynucleation and growth in ion-implanted single-crystal BaTiO3 layer is proposed, and cavity formation is related to the measured mechanical properties to better understand hydrogen implantation-induced layer transfer processes for ferroelectric thin films. The critical radius for cavitynucleation was determined experimentally from blistering experiments performed under isochronal anneal conditions and was calculated using continuum mechanical models for deformation and fracture, together with thermodynamic models. Based on thermodynamic modeling, we suggest that cavitiesgrow toward the cracking criteria at a critical blister size whereupon gas is emitted from ruptured cavities. The main driving force for layer splitting is the …
A New Solid Oxide Molybdenum–Air Redox Battery,
2015
University of South Carolina - Columbia
A New Solid Oxide Molybdenum–Air Redox Battery, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang
Kevin Huang
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 …
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell,
2015
University of South Carolina - Columbia
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling
Kevin Huang
Energy dispersive spectrometry line scan and ac impedance spectroscopy were used in this study to investigate the chemical reactions between two cathode materials, La0.84Sr0.16MnO3 (LSM), La0.5Sr0.5CoO3-δ (LSC), and the electrolyte La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM). Significant interdiffusions of Co into LSGM and Ga into LSC were found at an LSC/LSGM interface even at relatively low fabrication temperatures. In contrast, only small interdiffusions of Mn into LSGM and Ga into LSM were detected at the LSM/LSGM interface even though it was fired at 1470°C. The …
Combining Proton Conductor Bazr0.8Y0.2O3-Δ With Carbonate: Promoted Densification And Enhanced Proton Conductivity,
2015
University of South Carolina - Columbia
Combining Proton Conductor Bazr0.8Y0.2O3-Δ With Carbonate: Promoted Densification And Enhanced Proton Conductivity, Xue Li, Nansheng Xu, Lingling Zhang, Kevin Huang
Kevin Huang
No abstract provided.
H3Po4-Imbibed Three-Dimensional Polyacrylamide/Polyacrylamide Hydrogel As A High-Temperature Proton Exchange Membrane With Excellent Acid Retention,
2015
University of South Carolina - Columbia
H3Po4-Imbibed Three-Dimensional Polyacrylamide/Polyacrylamide Hydrogel As A High-Temperature Proton Exchange Membrane With Excellent Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang
Kevin Huang
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 advantages along with simple and low-cost synthesis …
Sol-Gel Synthesis Of A New Oxide-Ion Conductor Sr- And Mg-Doped Lagao3 Perovskite,
2015
University of South Carolina - Columbia
Sol-Gel Synthesis Of A New Oxide-Ion Conductor Sr- And Mg-Doped Lagao3 Perovskite, Kevin Huang, Man Feng, John Goodenough
Kevin Huang
No abstract provided.
A Novel Intermediate-Temperature All Ceramic Iron–Air Redox Battery: The Effect Of Current Density And Cycle Duration,
2015
University of South Carolina - Columbia
A Novel Intermediate-Temperature All Ceramic Iron–Air Redox Battery: The Effect Of Current Density And Cycle Duration, Xuan Zhao, Xue Li, Yunhui Gong, Nansheng Xu, Kevin Huang
Kevin Huang
We here report the energy storage characteristics of a new all ceramic iron–air redox battery comprising of a reversible solid oxide fuel cell as the charger/discharger and a Fe–FeOx redox couple as the chemical storage bed. The effects of current density and cycle duration on specific energy and round trip efficiency of the new battery have been systematically studied at 650°C and 550°C. The results explicitly show that current density is the most influential variable on the performance, signifying the importance of improving electrochemical performance of the reversible solid oxide fuel cell.
High Conductivity Mixed Oxide-Ion And Carbonate-Ion Conductors Supported By A Prefabricated Porous Solid-Oxide Matrix,
2015
University of South Carolina - Columbia
High Conductivity Mixed Oxide-Ion And Carbonate-Ion Conductors Supported By A Prefabricated Porous Solid-Oxide Matrix, Lingling Zhang, Xue Li, Siwei Wang, Kevin Romito, Kevin Huang
Kevin Huang
No abstract provided.
Beneficial Effects Of Mg-Excess In La1-XSrXGa1-YMgY + ZO3-Δ As Solid Electrolyte,
2015
University of South Carolina - Columbia
Beneficial Effects Of Mg-Excess In La1-XSrXGa1-YMgY + ZO3-Δ As Solid Electrolyte, Xuan Zhao, Xue Li, Nansheng Xu, Kevin Huang
Kevin Huang
One of the paramount obstacles to the commercialization of La1-xSrxGa1-yMgyO3-δ (LSGM)-based intermediate-temperature solid oxide fuel cells is the high cost and low mechanical strength associated with the use of Ga2O3. We demonstrate in this study the use of excess Mg-doping on Ga-site as a means of lowering cost and potentially increasing mechanical strength of the final LSGM product. Conventional techniques such as XRD, SEM and AC impedance spectroscopy are applied to characterize the synthesized Mg-excess La0.8Sr0.2Ga0.83Mg0.17 + zO3-δ. The microstructures revealed by SEM indicate an increased appearance of the Mg-rich second phase along the grain-boundaries with increasing Mg-excess level even …
Development Of Delta-Type High Power Density Solid Oxide Fuel Cells At Siemens Stationary Fuel Cells,
2015
University of South Carolina - Columbia
Development Of Delta-Type High Power Density Solid Oxide Fuel Cells At Siemens Stationary Fuel Cells, Kevin Huang
Kevin Huang
This paper describes recent development in Siemens Stationary Fuel Cells of Delta-type high power density solid oxide fuel cells, the foundation for future high power and high efficiency electrical power generation. Relatively high-level overviews are given in the areas of cell materials, basic cell design, basic bundle design and basic module design. The testing results of six-cell Delta 9 bundle and single Delta 8 cell are particularly highlighted to demonstrate the unique advantage of high power density and high total power presented by Delta geometry.
Mixed Oxide-Ion And Carbonate-Ion Conductors (Moccs) As Electrolyte Materials For Solid Oxide Fuel Cells,
2015
University of South Carolina - Columbia
Mixed Oxide-Ion And Carbonate-Ion Conductors (Moccs) As Electrolyte Materials For Solid Oxide Fuel Cells, Xue Li, Guoliang Xiao, Seung Min Lee, Kevin Huang
Kevin Huang
A systematic investigation on the effective ionic conductivity (σm) of a novel intermediate temperature mixed oxide-ion and carbonate-ion conductor (MOCC) consisting of a ceria and a carbonate is reported. The study explicitly shows that the observed remarkable temperature-dependent σm is primarily the result of softening/melting of the carbonate phase as the physical state of the carbonate phase transforms from solid, softened to molten. DSC analysis complements the understanding of the observed electrical behavior by revealing temperatures of melting and solidification in agreement with the onset temperatures of σm. In addition, the measured σm agrees reasonably well with those simulated by …
Silver-Molten Carbonate Composite As A New High-Flux Membrane For Electrochemical Separation Of Co2 From Flue Gas,
2015
University of South Carolina - Columbia
Silver-Molten Carbonate Composite As A New High-Flux Membrane For Electrochemical Separation Of Co2 From Flue Gas, Nansheng Xu, Xue Li, Maxwell Franks, Hailei Zhao, Kevin Huang
Kevin Huang
No abstract provided.
High Co2 Permeation Flux Enabled By Highly Interconnected Three-Dimensional Ionic Channels In Selective Co2 Separation Membranes,
2015
University of South Carolina - Columbia
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 Harris, Wilson Chiu
Kevin Huang
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 also have an excellent agreement with …
Fuel Utilization And Fuel Sensitivity Of Solid Oxide Fuel Cells,
2015
University of South Carolina - Columbia
Fuel Utilization And Fuel Sensitivity Of Solid Oxide Fuel Cells, Kevin Huang
Kevin Huang
No abstract provided.
Sr‐ And Ni‐Doped Lacoo3 And Lafeo3 Perovskites: New Cathode Materials For Solid‐Oxide Fuel Cells,
2015
University of South Carolina - Columbia
Sr‐ And Ni‐Doped Lacoo3 And Lafeo3 Perovskites: New Cathode Materials For Solid‐Oxide Fuel Cells, Kevin Huang, Hee Y. Lee, John B. Goodenough
Kevin Huang
An improved cathode material for a solid‐oxide fuel cell would be a mixed electronic and oxide‐ion conductor with a good catalytic activity for oxygen reduction at an operating temperature T op ≥ 700°C and a thermal expansion matched to that of the electrolyte and interconnect. We report on the properties of Sr‐ and Ni‐doped LaCoO3 and LaFeO3 perovskites that meet these criteria. Single‐phase regions were determined by X‐ray diffraction, and thermogravimetric analysis measurements were used to obtain the temperatures above which oxygen loss, and hence oxide‐ion conductivity, occurs. The conductivity and Seebeck measurements indicate the coexistence of both …
Activity Of Bi2O3 In Bi2O3 Y2O3 Oxygen Ion Conductor,
2015
University of South Carolina - Columbia
Activity Of Bi2O3 In Bi2O3 Y2O3 Oxygen Ion Conductor, Kevin Huang, Changzhen Wang, Xiuguang Xu
Kevin Huang
No abstract provided.
Heat Conduction And Seebeck Effect In Oxygen Cell,
2015
University of South Carolina - Columbia
Heat Conduction And Seebeck Effect In Oxygen Cell, Kevin Huang, Yuhua Xia, Qingguo Liu
Kevin Huang
No abstract provided.
