Resume

• 2013

  Doctor of Philosophy (Ph.D.)

  Materials Science

  Batteries

  Nanocomposites

  Energy Storage Devices

  Texas A&M University

  4.0 out of 4.0

• 2008

  Bachelor of Science

  Apoliced Physics

  Materials Science

  Soft Materials

  Mechanical Characterizations

  Xi'an Jiaotong University

• C++

  Teaching

  LaTeX

  LabVIEW

  Materials Science

  Data Analysis

  Programming

  Laboratory

  Research

  Nanotechnology

  Microsoft Office

  Chemistry

  Science

  AutoCAD

  Microsoft Excel

  Matlab

  PowerPoint

  Statistics

  Physics

  Microsoft Word

  Micro- and Nano-Structured Vanadium Pentoxide (V2O5) for Electrodes of Lithium-Ion Batteries

  Vanadium pentoxide (V2O5) has played important roles in lithium-ion batteries due to its unique crystalline structure. To assist researchers understanding the roles this material plays

  a comprehensive and critical review is conducted based on about 250 publications. Here

  we report basics and applications of micro- and nano-materials of V2O5 and V2O5-based composites. The comparative and statistical analysis leads to the discovery of several interesting phenomena. The V2O5 electrodes with two lithium ions have a favorable capacity performance with reversible phase formation. The excellent capacity retention is displayed in the V2O5 electrodes with one lithium ion inserted. In the case of three lithium ions insertion

  it was found that the irreversible formation of the phase ω in LixV2O5 leads to its control. In addition

  effects of additives on electrode performance

  circuitry models of performance

  as well as reaction routes are studied. Two unprecedented concepts of the “high capacity band” and “empirical total capacity retention” are proposed though the comprehensive statistical analysis of the reviewed data. This review provides a comprehensive collection of information of state-of-the-art and recent advancement in V2O5 and V2O5-based composite materials for electrodes. Researchers could use the information to design and develop advanced electrodes for future batteries.

  Micro- and Nano-Structured Vanadium Pentoxide (V2O5) for Electrodes of Lithium-Ion Batteries

  Dilworth Y. Parkinson

  Jorge M. González

  Carlos Sanchez

  Yunyun Chen

  Journal of Synchrotron Radiation

  Nanomaterials are being used in medicine

  manufacturing and consumer products

  but their effects on organisms and the environment are not well understood because of the difficulty in detecting them. Here dual-energy X-ray K-edge subtraction was used to track two-dimensional yttrium oxide nanoparticles (which can be found in such household objects as color televisions) in adult mealworms (Tenebrio molitor). The insects ingested nanoparticle-infused feed for different time periods

  up to 24 h

  and the nanoparticles could then be identified at several locations in the insects' head

  thorax and abdomen

  mostly within the digestive tract. In time

  all particles were excreted.

  Observation of two-dimensional yttrium oxide nanoparticles in mealworm beetles (Tenebrio molitor)

  Partha Mukherjee

  Winson C.H. Kuo

  Yan Chen

  Daniel Juarez-Robles

  The electrochemical performance of anodes made of transition metal oxides (TMOs) in lithium-ion batteries (LIBs) often suffers from their chemical and mechanical instability. In this research

  a novel electrode with a hierarchical current collector for TMO active materials is successfully fabricated. It consists of porous nickel as current collector on a copper substrate. The copper has vertically aligned microchannels. Anatase titanium dioxide (TiO2) nanoparticles of ∼100 nm are directly synthesized and cast on the porous Ni using a one-step process. Characterization indicates that this electrode exhibits excellent performance in terms of capacity

  reliable rate

  and long cyclic stability. The maximum insertion coefficient for the reaction product of LixTiO2 is ∼0.85

  a desirable value as an anode of LIBs. Cross-sectional SEM and EDS analysis confirmed the uniform and stable distribution of nanosized TiO2 nanoparticles inside the Ni microchannels during cycling. This is due to the synergistic effect of nano-TiO2 and the hierarchical Cu/Ni current collector. The advantages of the Cu/Ni/TiO2 anode include enhanced activity of electrochemical reactions

  shortened lithium ion diffusion pathways

  ultrahigh specific surface area

  effective accommodation of volume changes of TiO2 nanoparticles

  and optimized routes for electrons transport.

  Hierarchical Structured Cu/Ni/TiO2 Nanocomposites as Electrodes for Lithium-ion Batteries

  Abraham Clearfield

  Hyunho Choi

  Yuwei Kan

  Dynamic light scattering (DLS) is one of the most adapted methods to measure the size of nanoparticles

  as referred to the hydrodynamic radii (Rh). However

  the Rh represents only that of three-dimensional spherical nanoparticles. In the present research

  the size of two-dimensional (2D) nanoparticles of yttrium oxide (Y2O3) and zirconium phosphate (ZrP) was evaluated through comparing their hydrodynamic diameters via DLS with lateral sizes obtained using scanning and transmission electron microscopy. We demonstrate that the hydrodynamic radii are correlated with the lateral sizes of both square and circle shaped 2D nanoparticles. Two proportional coefficients

  i.e.

  correcting factors

  are proposed for the Brownian motion status of 2D nanoparticles. The correction is possible by simplifying the calculation of integrals in the case of small thickness approximation. The correcting factor has great significance for investigating the translational diffusion behavior of 2D nanoparticles in a liquid and in effective and low-cost measurement in terms of size and morphology of shape-specific nanoparticles.

  Correlating hydrodynamic radii with that of two-dimensional nanoparticles

  Hong LiangEmail author Affiliat

  Dilworth Y. Parkinson

  Jorge M. González

  Mauricio de Almeida

  Carlos Sanchez

  Yunyun Chen

  Journal of Nanobiotechnology

  Background\nThe potential transfer of engineered nanoparticles (ENPs) from plants into the food chain has raised widespread concerns. In order to investigate the effects of ENPs on plants

  young cabbage plants (Brassica oleracea) were exposed to a hydroponic system containing yttrium oxide (yttria) ENPs. The objective of this study was to reveal the impacts of NPs on plants by using K-edge subtraction imaging technique.\n\nResults\nUsing synchrotron dual-energy X-ray micro-tomography with K-edge subtraction technique

  we studied the uptake

  accumulation

  distribution and concentration mapping of yttria ENPs in cabbage plants. It was found that yttria ENPs were uptaken by the cabbage roots but did not effectively transferred and mobilized through the cabbage stem and leaves. This could be due to the accumulation of yttria ENPs blocked at primary-lateral-root junction. Instead

  non-yttria minerals were found in the xylem vessels of roots and stem.\n\nConclusions\nSynchrotron dual-energy X-ray micro-tomography is an effective method to observe yttria NPs inside the cabbage plants in both whole body and microscale level. Furthermore

  the blockage of a plant’s roots by nanoparticles is likely the first and potentially fatal environmental effect of such type of nanoparticles.\n\nKeywords\n\nSynchrotron X-ray micro-tomography K-edge subtraction imaging Yttria nanoparticles Cabbage Accumulation

  Observation of yttrium oxide nanoparticles in cabbage (Brassica oleracea) through dual energy K-edge subtraction imaging

  Hong Liang

  The design of electrodes for the electrochemical energy storage devices

  particularly Lithium ion batteries (LIBs) and Supercapacitors (SCs)

  has extraordinary importance in optimization of electrochemical performance. Regardless of the materials used

  the architecture of electrodes is crucial for charge transport efficiency and electrochemical interactions. This report provides a critical review of the prototype architectural design and micro- and nano-material properties designated to electrodes of LIBs and SCs. An alternative classification criterion is proposed that divides reported hierarchical architectures into two categories: aligned and unaligned structures. The structures were evaluated and it was found that the aligned architectures are superior to the unaligned in the following characteristics: 1) highly-organized charger pathways

  2) tunable interspaces between architecture units

  and 3) good electric-contacted current collectors prepared along with electrodes. Based on these findings

  challenges and potential routes to resolve those are provided for future development.

  Hierarchical Micro-architectures of electrode for energy storage

  Hae-Kwon Jeong

  Jingze Sun

  Hierarchical nanomaterials are of great interest due to their unique surface properties such as large surface area and high reactivity. In the present research

  super-hierarchical (porous-) nickel hosted vanadium oxide (Ni/porous-Ni/V2O5) nanocomposite was fabricated using a simple

  low-cost

  and environmentally-friendly method. A nickel substrate was electrodeposited with vertical pores of ∼10 μm in diameter through hydrogen bubbles as “dynamic templates”. Two-dimensional V2O5 nanosheets were subsequently synthesized directly on the Ni/porous-Ni substrate surface using a hydrothermal method followed by annealing. Peony-like micro-configuration of V2O5 was found and crystallography was confirmed using high-resolution characterization. Further analysis indicated that the interface was formed between Ni (111) and V2O5 (100). The small lattice mismatch of 1.2% at the interface facilitated the 2D directional growth of V2O5 nanosheets on the Ni surface. The specific surface area and porosity of annealed Ni/porous-Ni/V2O5 nanocomposite was as high as 15.3 m2 g−1 and 55.1%. The advantage of the structure was found in the heat dissipation. Such super-hierarchical structure is anticipated to be used in applications such as coatings to improve cooling of macro- and micro-devices.

  Super-hierarchical Ni/porous-Ni/V2O5 nanocomposites

  Brady Reed

  Keeley Coburn

  A novel hierarchical structure is reported that comprises micro-channeled nickel deposited onto a copper substrate. The fabrication process is a one-step galvanostatic electrodeposition in a system containing a Cu cathode

  graphite anode

  and Ni2+/NH 4 + electrolyte. Results were obtained by the characterization of vertically aligned micro-channels in Ni. The pore density

  depth

  and diameter are controlled by varying electrodeposition conditions. The addition of ammonium ions

  increased current

  and longer deposition time are found to promote formation of high density pores with small diameters leading to those micro-channels. The channel’s optimum diameter ranged from 8 to 10 µm with depths of 20–25 µm. Adding ammonium ions also generated streams of hydrogen bubbles that formed on the cathode surface. Those bubbles hinder the nucleation of Ni

  resulting in the selective nucleation and therefore the growth of micro-channels. The novel hierarchical Ni/Cu hybrids have the potential to be used for current collectors for battery electrodes

  substrates to grow nanostructured oxides

  and among others.

  Hierarchical structured nickel–copper hybrids via simple electrodeposition

  Li Liu

  Ye Xu

  While bulk gold is largely considered chemically inert

  nanostructured Au has demonstrated catalytic activities

  under mild conditions

  for reactions such as CO oxidation [1]

  selective hydrocarbon oxidation [2]

  selective hydrogenation [3]

  etc. In general

  the catalytic activity of nanostructured Au has been explained in terms of synergetic effects between the substrate and Au [4–6] and under–coordinated Au atoms in the nanostructured Au [7]. Nanostructured Au quantized in the vertical direction has also exhibited interesting catalytic properties. Freund and coworkers has demonstrated the exclusive adsorption of CO molecules on the perimeter of two–dimensional (2–D) Au islands on MgO⁄Ag(111) [8]. Goodman and coworkers have shown that the catalytic CO oxidation activity of the second Au layer is four times higher than the first and thicker Au layers on TiOx⁄Mo(112) [9].\n\nThe formation of 2–D Au islands on graphene⁄Ru (0001) moiré structure is an intriguing example of nanostructured au whose formation is assisted by a template surface. Experimental techniques

  such as Scanning Tunneling Microscopy (STM)

  Auger Electron Spectroscopy (AES)

  Low Electron Energy Diffraction (LEED)

  Polarization Modulated Infrared Reflection Adsorption Spectroscopy (PM–IRAS)

  and High Resolution Electron Energy Loss Spectroscopy (HREELS)

  were combined with Density Functional Theory (DFT) simulations to characterize those 2–D Au islands. We found that those 2–D Au islands are structurally flexible and the adsorbed CO molecules can be titrated by O2 at Liquid Nitrogen (LN2) temperatur

  Two-Dimensional Gold Islands on Graphene/Ru (0001) Moiré Structure

  Partha Mukherjee

  Daniel Juarez-Robles

  New materials are critically needed for advanced energy storage devices due to the limited performance of currently used electrodes. We report an alternative approach to fabricate a novel class of nanostructured cathodes with a three-dimensional configuration that shows superior performance. A superhierarchical Ni/porous-Ni/V2O5 nanocomposite is designed and synthesized using a simple electrodeposition process followed by a hydrothermal treatment. Hierarchical V2O5 nanostructures are deposited directly on a Ni microchanneled current collector. Morphological characterization shows that two-dimensional V2O5 nanosheets are uniformly distributed on the porous Ni substrate. A peony-like V2O5 microstructure arises having a diameter of ∼4 μm. The superhierarchical Ni/porous-Ni/V2O5 nanocomposite exhibits superior electrochemical performance as a binder-free cathode. Its maximum reversible discharge capacity reaches 165.6 mAh g–1 at 0.2 C

  which is higher than the theoretical capacity of bulk V2O5 cathodes. The capacity retains 90.9% and 72.4% after 100 cycles at 0.2 C and 500 cycles at 3.0 C

  respectively. The stable rate capability is also confirmed. Our analysis indicates that such high performance is attributed to the synergistic effects of: the hierarchical structure

  microchanneled Ni current collectors

  two-dimensional V2O5 nanostructured active materials

  and the binder-free processing. This research shows significant promise for use of superhierarchical structures in future of rechargeable batteries.

  Superhierarchical nickel-vanadia nanocomposites for lithium storage

  Jacob Staffel

  Michael Sanguino

  Cassidy Shaver

  Hyunho Choi

  Materials with textured surfaces have attracted great interests due to the unique characteristics

  such as high specific surface area

  light weight

  and excellent electronic or magnetic performances. Current approaches to manufacture porous materials have been limited by being complicated

  costly

  and time-consuming. Here we demonstrate a facile and cost-effective method to fabricate an unprecedented macropore-arrayed structure on an aluminum foil through electrochemical etching. The process was carried out at a galvanostatic mode of electrochemical reaction

  in which the aluminum foil was the working electrode. The electrolytic solution contained perchloric acid and ethanol. Pores were observed using various characterization techniques such as digital optical microscopy

  scanning electron microscopy

  and interferometer. With extended etching time

  the pore density was increased while the pore size remained to be consistent (~15 μm in diameter). Further examination showed that the surface hydrophilicity was improved due to the existence of pores. The increased pore density is responsible for reduced contact angle. The new finding offers the potential economical and practical applications of the pored aluminum surface in designing novel hierarchical structures.

  Electrochemical synthesis and hydrophilicity of micro-pored aluminum foil

  Yue

  Department of Mechanical Engineering at Texas A&M University

  Lawrence Berkeley National Laboratory

  UC Berkeley

  Texas A&M University

  Lawrence Berkeley National Laboratory

  Lawrence Berkeley National Laboratory

  Xi'an Jiaotong University

  College Station

  Texas

  Graduate Teaching Assistant (GTA) of ENGR 111/112

  Supervisor: Dr. Valerie Taylor\n•\tInstructed the introduction to engineering (including ethics

  problem solving

  and engineering project management) with LabVIEW

  MATLAB

  and CAD software learning to freshman students at TAMU;\n•\tAssisted the instructor to communicate with students about the feedback of the teaching;\n•\tOrganized the grading tasks by distributing them to two or three undergraduate peer-teachers;\n•\tParticipated in the coordination among 25 GTAs for the arrangement of project demonstrations.

  Graduate Teaching Assistant

  Texas A&M University

  Bryan/College Station

  Texas Area

  Department of Materials Science and Engineering

  Ph.D. student

  Texas A&M University

  Berkeley

  California

  Department of Physics

  Department of Earth and Planetary Sciences

  Undergraduate Visiting Student

  UC Berkeley

  College Station

  Texas

  Graduate Student Mentor of ENGR 491-506 (Undergraduate Research)\nResearch Project Title: Fabrication and Electrochemical Analysis of Hierarchical Electrode;\n•\tLead 13 undergraduate students with a diversity of class levels and majors as a team;\n•\tCoordinated with students and the supervisor for the sharing of the research ideas;\n•\tDesigned experiments and prepared the metal-metal oxide composites for electrodes;\n•\tAccomplished the characterization

  analyzed data

  and presented the results by poster sessions.

  Gradue Student Mentor

  Texas A&M University

  Berkeley

  California

  Graduate Visiting Student at Beamline 8.3.2

  PI: Dr. Hong Liang\n•\tObtained the operation skill of the hard X-ray tomography facility at Beamline 8.3.2;\n•\tTested biological bodies of American cockroach and fire ants using self-designed specific X-ray tomography sample holder to facilitate the stable mounting on the tomography facility;\n•\tResearched dosed nanoparticles inside the biological bodies through the X-ray tomography.

  Graduate Visiting Researcher

  Lawrence Berkeley National Laboratory

  College Station

  Texas

  50% Full-time Equivalent Graduate Assistant Lecturer of MEEN 222-503 (Materials Science)\n•\tInstructed a class with 58 undergraduate students with diversity of race

  class levels

  and majors;\n•\tOrganized the in-class quizzes

  homework

  team projects

  mid-term and final exams;\n•\tLead a teaching team including myself

  a graduate teaching assistant

  and an undergraduate grader; \n•\tCommunicated with students about their learning feedback and evaluation to my teaching.

  Graduate Assistant Lecturer

  Department of Mechanical Engineering at Texas A&M University

  Berkeley

  California

  Lawrence Berkeley National Laboratory

  Texas A&M University

  College Station

  Texas

  •\tRegenerated the chamber reaction system using ultra-high vacuum technology;\n•\tStudied the X-ray Photoelectron Spectroscopy operation and related sample preparations;\n•\tProposed a novel design of the reaction chamber for the testing of solid-liquid interface reactions.

  Graduate Research Assistant

  Berkeley

  California

  Molecular Foundry

  Undergraduate Visiting Researcher

  Lawrence Berkeley National Laboratory

  College Station

  Texas

  Graduate Research Assistant at Surface and Interface Science Laboratory

  Adviser: Dr. Hong Liang\n•\tDissertation topic: Synthesis and Characterization of Novel Nanocomposites for Energy Storage;\n•\tImproved the surface area of current collectors for electrodes using two types of novel metallic pore-array hierarchical nanomaterials;\n•\tAchieved one of the best electrochemical performance using two novel types of hierarchical shape-specific transition metal oxide nanoparticles for the application lithium-ion batteries;\n•\tEnhanced the surface area and hydrophilicity of the aluminum-based micro-porous film;\n•\tResolved the correlation between the hydrodynamic radius and lateral dimensions of 2-dimensional nanoparticles by constructing a mathematical model;\n•\tProposed novel concepts to characterize the electrochemical performance of hierarchical/un-hierarchical architectures of the electrode nanomaterials;\n•\tAccomplished several projects with the collaboration of researchers from Department of Chemistry

  Department of Mechanical Engineering

  and Department of Electrical and Computer Engineering at TAMU and the National Institute of Standard and Technology (NIST) about the metallic oxide nanoparticles.

  Graduate Research Assistant

  Texas A&M University

  Xi‘an

  Shaanxi

  China

  Center for Advancing Materials Performance from the Nanoscale

  Department of Materials Science and Engineering\n•\tSelf-designed and constructed a novel facility for the mechanical testing of soft materials;\n•\tMeasured the tensile properties of raw wheat noodles by using this facility;\n•\tAnalyzed the mechanism of the superplasticity of soft materials;\n•\tCollected and accomplished work and wrote a report for undergraduate senior design.

  Undergraduate Research Assistant

  Xi'an Jiaotong University

  Zhiwei Shan

  CN 102809505 A

  The 3rd prize of the Neville B. Smith Student Poster Award

  Advanced Light Sources (ALS) annual user meeting

  Lawrence Berkeley National Laboratory

  The Certificate of Recognition Award of 2016 Engineering Showcase

  Dwight Look College of Engineering at Texas A&M University

  The bronze prize (ranking 3) of Excellent Posters Award

  International Workshop on Advancing Materials Performance from the Nanoscale

  Xi’an

  China

  2017-18 Texas A&M Energy Institute Fellowship

  The prestige and highly-competitive graduate fellowship supported by Texas A&M Energy Institute

  Texas A&M Energy Institute

  2016 Graduate Teaching Fellowship of Dwight Look College of Engineering

  Dean Office

  Dwight Look College of Engineering at Texas A&M University