DOCSLIB.ORG

University of California Riverside

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
University of California Riverside UNIVERSITY OF CALIFORNIA RIVERSIDE Three Dimensional Hybrid Nanostructures for Renewable Energy Storage Applications A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Materials Science and Engineering by Yiran Yan June 2018 Dissertation Committee: Dr. Mihrimah Ozkan, Co-Chairperson Dr. Cengiz S. Ozkan, Co-Chairperson Dr. Kambiz Vafai Dr. Jianlin Liu i Copyright by Yiran Yan 2018 ii The Dissertation of Yiran Yan is approved: Co-Chairperson Co-Chairperson University of California, Riverside iii ACKNOWLEDGEMENT I would like to acknowledge the great support and help from all of my advisors, lab mates, peer scientists, family and friends during the past five years of research and study. First of all, I would like to thank both of my advisors, Dr. Cengiz Ozkan and Dr. Mihri Ozkan. They offered help and advising during my most difficult time in graduate school. Their guidance and encouragement, both in academics and life, enlightens me to pursuit my Ph.D with confidence and persistence. I would also like to thank all my committee members, Dr. Kambiz Vafai and Dr. Jianlin Liu for your time and help to the completion of my Ph.D. Moreover, many thanks go to all my peers in Ozkan Lab and UCR: Dr. Changling Li, Dr. Chueh Liu, Dr. Zafer Mutlu, Jingjing Liu, Rachel Ye, Jeffery Bell, Bo Dong and Dr. Wensen Jiang. Their suggestions and support helped me so much in my research and life. In addition, I am very thankful of our collaborators, Dr. Paul Weiss, Qing Yang in UCLA, for extending the scope of our research. Last, I would like to acknowledge my son Charles Yang and my family. I had my son during my last year of graduate school and enabled me not only becoming an independent scientist, but also a strong mom. And thanks to the great support from my family, their efforts and love allowed me being able to focus on my research and study. iv COPYRIGHT ACKNOWLEDGEMENT The text and figures in Chapter 2, in part or in full, are a reprint of the material as it appears in the published work: Y. Yan, et al., “Bundled and dispersed carbon nanotubes integrated to graphitic materials as free-standing hybrid lithium ion battery anodes,” In Submission. The text and figures in Chapter 3, in part or in full, are a reprint of the material as it appears in a completed work: C. Li, et al., “The Kinetics and Physical Evolution of Binary Si-Polymer Systems for Electrochemical Energy Storage,” RSC Advances. The text and figures in Chapter 4, in part or in full, are a reprint of the material as it appears in the published work: Y. Yan, et al., “Silicon/Polypyrrole hybrid Nanocomposites with Controllable Dimensions for Lithium Ion Battery Anodes,” In Submission. v Dedicated to my son, Charles vi ABSTRACT OF THE DISSERTATION Three Dimensional Hybrid Nanostructures for Renewable Energy Storage Applications by Yiran Yan Doctor of Philosophy, Graduate Program in Materials Science Engineering University of California, Riverside, June 2018 Dr. Mihrimah Ozkan, Co-Chairperson Dr. Cengiz S. Ozkan, Co-Chairperson The increasing concern about global energy crisis and continuing deteriorating environmental issues has pushed the investigation and use of clean and renewable energies. However, in order to efficiently utilize these intermittent energies, an advanced energy storage system must be developed. Lithium ion batters (LIBs) are among the most promising energy storage devices with high energy and power density at relatively low cost. Although commercial LIBs have being announced for more than 30 years, the major electrode materials still remain the same. The rising number of electric vehicles and portable electronics requires advanced lithium ion batteries with higher capacity at lower weight and more affordable price. Herein, there anode materials systems were developed with three dimensional (3D) hybrid nanostructure for improving current commercial graphite anode, as well as enhancing the next-generation silicon based anode. vii Three dimensional carbon nanotubes (CNTs) on graphite foam was fabricated as free- standing LIB anode. Morphologies of carbon nanotube were controlled via annealing process during growth. The resulting bundled vs. dispersed CNTs show different electrochemical performances. Dispersed CNTs yields superior capacity (over 800 mAh/g) over 120 cycles due to high surface area and efficient ion/electron transportation. A novel 3D networks synergizing conductive polymers, polypyrrole and polyaniline, with nanostructured silicon particles for lithium ion battery anode was fabricated. The bindery hybrid structures show much enhanced battery performance compared with silicon/non-conductive polymer anode. Si nanoparticles (Si NPs) with polypyrrole hybrid structure shows ~1050 mAh/g capacity at fast charging rate of 1C. The three dimensional hydrogel butters the stress caused by silicon expansion during lithiation. The higher conductivity of polypyrrole over polyaniline contributes to its excellent battery performance. High performance conductive binder, polypyrrole, was used to form hybrid 3D network with Si nanowires fabricated via directly metal-assisted chemical etching of silicon wafers. The hybrid nanocomposites exhibit outstanding battery performance of 1689 mAh/g over 600 cycles, which significantly out-performed Si NWs with traditional poly acrylic acid binder. Such enhancement is ascribed to the cylindrical nanostructure of single crystal silicon that could withstand stress during volume expansion and the highly conductive 3D network of polypyrrole provides space accommodating internal stress and enhanced electrode conductivity. viii TABLE OF CONTENTS ACKNOWLEDGEMENT-----------------------------------------------------------------------IV COPYRIGHT ACKNOWLEDGEMENT------------------------------------------------------V Dedicated to my son, Charles---------------------------------------------------------------------VI ABSTRACT OF THE DISSERTATION-------------------------------------------------------VII TABLE OF CONTENTS -----------------------------------------------------------------------IX LIST OF FIGURES--------------------------------------------------------------------------------XI CHAPTER 1: INTRODUCTION------------------------------------------------------------------1 1.1 ENERGY STORAGE TECHNOLIGIES----------------------------------------------------1 1.2 CARBON BASED MATERIALS AS LITHIUM BATTERY ANODES OR ELECTRODE MATERIALS ADDITIVES------------------------------------------------------3 1.3 SILICON AS NEXT GENERATION ANODE MATERIALS---------------------------4 1.4 PERSPECTIVE----------------------------------------------------------------------------------8 1.5 REFERENCES-----------------------------------------------------------------------------------9 CHAPTER 2: BUNDLED AND DISPERSED CARBON NANOTUBES INTEGRATED TO GRAPHITIC MATERIALS AS FREE-STANDING HYBRID LITHIUM ION BATTERY ANODES----------------------------------------------------------------------------18 ABSTRACT---------------------------------------------------------------------------------18 2.1 INTRODUCTION------------------------------------------------------------------------------19 2.2 MATERIALS AND METHODS-------------------------------------------------------------21 2.3 RESULTS AND DISCUSSIONS-----------------------------------------------------------23 2.4 CONCLUSION--------------------------------------------------------------------------------18 2.5 REFERENCES---------------------------------------------------------------------------------29 CHAPTER 3: SILICON-CONDUCTIVE POLYMER HYBRID NANOCOMPOSITES SYSTEM FOR LITHIUM ION BATTERY ANODES----------------------------------42 ABSTRACT---------------------------------------------------------------------- ---42 3.1 INTRODUCTION------------------------------------------------------------------43 3.2 MATERIALS AND METHODS-----------------------------------------------------46 3.3 RESULTS AND DISCUSSIONS-------------------------------------------------------48 3.4 CONCLUSION-------------------------------------------------------------------------------58 3.5 REFERENCES-------------------------------------------------------------------------------60 ix CHAPTER 4: THREE DIMENSIONAL SILICON NANOWIRE/CONDUCTIVE POLYMER NETWORK FOR HIGH PERFORMING LITHIUM ION BATTERY ANODE----------------------------------------------------------------------------------------------81 ABSTRACT------------------------------------------------------------------------------------81 4.1 INTRODUCTION-----------------------------------------------------------------------------81 4.2 MATERIALS AND METHODS----------------------------------------------------84 4.3 RESULTS AND DISCUSSIONS-------------------------------------------------------86 4.4 CONCLUSION---------------------------------------------------------------------------93 4.5 REFERENCES--------------------------------------------------------------------------94 x LIST OF FIGURES Figure 1.1. Cycling performance of porous carbon impregnated sulfur cathode half cells. Different impregnation temperature of 25 ℃, 150 ℃ and 300 ℃ were used and corresponding battery performance shown, respectively. ------------------------------------14 Figure 1.2. Viral-templated Au NP assembly and Au/PPy nanopeapod gas sensor formation. (a) O2 plasma treatment of pre-patterned Pt three-terminal microelectrodes. (b) Adsorption of M13 bacteriophage template with Au affinity onto microelectrodes. (c) Selective binding of Au NP seeds to template. (d)
Load more

Recommended publications
  • Effect of Size and Shape on Electrochemical Performance of Nano-Silicon-Based Lithium Battery
    nanomaterials Article Effect of Size and Shape on Electrochemical Performance of Nano-Silicon-Based Lithium Battery Caroline Keller 1,2, Antoine Desrues 3, Saravanan Karuppiah 1,2, Eléa Martin 1, John P. Alper 2,3, Florent Boismain 3, Claire Villevieille 1 , Nathalie Herlin-Boime 3,Cédric Haon 2 and Pascale Chenevier 1,* 1 CEA, CNRS, IRIG, SYMMES, STEP, University Grenoble Alpes, 38000 Grenoble, France; [email protected] (C.K.); [email protected] (S.K.); [email protected] (E.M.); [email protected] (C.V.) 2 CEA, LITEN, DEHT, University Grenoble Alpes, 38000 Grenoble, France; [email protected] (J.P.A.); [email protected] (C.H.) 3 CEA, CNRS, IRAMIS, NIMBE, LEDNA, University Paris Saclay, 91191 Gif-sur-Yvette, France; [email protected] (A.D.); fl[email protected] (F.B.); [email protected] (N.H.-B.) * Correspondence: [email protected] Abstract: Silicon is a promising material for high-energy anode materials for the next generation of lithium-ion batteries. The gain in specific capacity depends highly on the quality of the Si dispersion and on the size and shape of the nano-silicon. The aim of this study is to investigate the impact of the size/shape of Si on the electrochemical performance of conventional Li-ion batteries. The scalable synthesis processes of both nanoparticles and nanowires in the 10–100 nm size range are discussed. In cycling lithium batteries, the initial specific capacity is significantly higher for nanoparticles than for nanowires. We demonstrate a linear correlation of the first Coulombic efficiency with the specific area of the Si materials.
    [Show full text]
  • Stable Cycling of Double-Walled Silicon Nanotube Battery Anodes Through Solid–Electrolyte Interphase Control
    LETTERS PUBLISHED ONLINE: 25 MARCH 2012 | DOI: 10.1038/NNANO.2012.35 Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control Hui Wu1‡, Gerentt Chan2‡, Jang Wook Choi1†, Ill Ryu1,YanYao1,MatthewT.McDowell1, Seok Woo Lee1, Ariel Jackson1, Yuan Yang1, Liangbing Hu1 and Yi Cui1,3* Although the performance of lithium ion-batteries continues to theory, there has been some success in addressing material stability improve, their energy density and cycle life remain insufficient issues by designing nanostructured silicon materials including for applications in consumer electronics, transport and large- nanowires, nanotubes, nanoporous films and silicon nanoparticle/ scale renewable energy storage1–5. Silicon has a large charge carbon composites18–26. This nanostructuring strategy has greatly storage capacity and this makes it an attractive anode material, increased the cycle life of silicon anodes to up to a few hundred but pulverization during cycling and an unstable solid–electro- cycles with 80% capacity retention24,25, although this is still far lyte interphase has limited the cycle life of silicon anodes to from the desired cycle life of thousands of cycles. hundreds of cycles6–11. Here, we show that anodes consisting SEI stability at the interface between the silicon and the liquid of an active silicon nanotube surrounded by an ion-permeable electrolyte is another critical factor in achieving a long cycle life. silicon oxide shell can cycle over 6,000 times in half cells This is very challenging, and has not been effectively addressed while retaining more than 85% of their initial capacity. The for materials undergoing large volume changes, as shown in the outer surface of the silicon nanotube is prevented from expan- schematic in Fig.
    [Show full text]
  • Atomic and Molecular Adsorptions of Hydrogen
    ATOMIC AND MOLECULAR ADSORPTIONS OF HYDROGEN AND OXYGEN ON SILICON NANOTUBES: AN AB INITIO STUDY by HAOLIANG CHEN Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT ARLINGTON May 2013 Copyright © by Haoliang Chen All Rights Reserved ACKNOWLEDGEMENTS I would like to express my gratitude to my advisor, Dr. Asok K. Ray for his guidance through the course of my study and research. I also would like to extend my thanks to my committee members, Dr. Nail Fazleev, Dr. Samarendra Mohanty, Dr. Zdzislaw Musielak, and Dr. Qiming Zhang, for their interest in my research work. I would also like to thank members of our research groups, Kapil Adhikari, Sarah Hernandez, Megan Lee, Dayla Morrison, Shafaq Moten, Sarah Duesman, Prabath Wanaguru, Raymond Atta-Fynn, Jianguang Wang and Ma Li for being very helpful throughout my research work. Their valuable suggestions during our regular research meetings have enriched my research experience. I am very grateful to Dr. Kapil Adhikari for being helpful in the very beginning of my research work. I am very grateful to my parents for providing me an encouraging environment during my undergraduate and graduate studies. Special thanks go to my girlfriend Yao Lin for her continuous support and care. Finally I would like to acknowledge the support from the Welch Foundation, Houston, Texas. April 15th, 2013 iii ABSTRACT ATOMIC AND MOLECULAR ADSORPTIONS OF HYDROGEN AND OXYGEN ON SILICON NANOTUBES: AN AB INITIO STUDY Haoliang Chen, PhD The University of Texas at Arlington, 2013 Supervising Professor: Asok K.
    [Show full text]
  • Mesoporous Nanotubes As Biomaterials
    Mesoporous Biomater. 2015; 2:33–48 Review Article Open Access Jeffery L. Coffer* Mesoporous nanotubes as biomaterials DOI 10.1515/mesbi-2015-0005 studies (within five years or less, where possible) ofse- Received October 1, 2015; accepted November 23, 2015 lected nanotubes that retain the desired porous dimen- sion in the mesoporous range relevant specifically to ei- Abstract: This review provides an overview of selected re- ther biosensing or therapeutic (e.g. principally drug deliv- cent research efforts that employ the use of mesoporous ery) applications. The discussion presented herein is or- nanotubes in a biomaterial context, e.g. principally as a ganized according to composition, sub-classified within therapeutic or biosensing platform. We focus on the com- each by fabrication, fundamental properties (biocompat- positions of alumina, boron nitride, silica, silicon, tita- ibility/biodegradability), and application. Highlights of a nia, and zinc oxide, along with selected accounts involv- given material’s desirable properties for a particular bio- ing single-walled carbon nanotubes. Where known, atten- relevant application are identified where possible, along tion is directed toward the biodegradability and biocom- with remaining challenges for clinical implementation. patibility of a given nanotube type, its tunability of size and surface chemistry, and relevance of these parameters to its function as a biomaterial. Keywords: nanotube, drug delivery, biosensor, alumina, 2 Alumina Nanotubes boron nitride, silica, silicon, titania We begin with a brief but focused discussion on nan- PACS: 68; 81 otubes of aluminum oxide (alumina, Al2O3). It is appro- priate to begin with this composition, given the fact that nanoporous alumina membranes are used in a widespread 1 Introduction manner as templates for the attempted formation of other nanotube types (titania, silicon) via infiltration, anneal- ing, and etching.
    [Show full text]
  • Silicon Nanotubes and Selected Investigations in Energy and Biomaterial Applications
    Silicon Nanotubes and Selected Investigations in Energy and Biomaterial Applications by ROBERTO GONZALEZ RODRIGUEZ Bachelor of sciences, July 2011 Universidad de las Americas Puebla Cholula, Puebla, Mexico Submitted to the Graduate Faculty of College of Science and Engineering Texas Christian University in partial fulfillment of the requirements for the degree of Doctor of Philosophy May 2017 ACKNOWLEDGEMENTS I would like to express my deep and sincere gratitude to my advisor, Dr. Jeffery L. Coffer, for his constant inspiration, guidance, encouragements and assistance throughout my graduate research at Texas Christian University. I would also like to thank to our collaborators Dr. Petra Granitzer and Dr. Klemens Rumpf of the Institute of Physics of Karl Franzens University, Saar group at the Hebrew University, Alexander T. Tesfaye and Thierry Djenizian at Aix-Marseille University, France. The Robert A.Welch Foundation is gratefully acknowledged for financial support. I also want to thank to Dr Coffer Lab members, Friends, and Family. ii Table of Contents Acknowledgments..........................................................................................................................ii Table of contents............................................................................................................................iii List of figures ................................................................................................................................vi List of tables .................................................................................................................................xii
    [Show full text]
  • Carbon Nanotubes Cross-Linked Zn2sno4 Nanoparticles/Graphene Networks As High Capacities, Long Life Anode Materials for Lithium Ion Batteries
    J Appl Electrochem (2016) 46:851–860 DOI 10.1007/s10800-016-0961-1 RESEARCH ARTICLE Carbon nanotubes cross-linked Zn2SnO4 nanoparticles/graphene networks as high capacities, long life anode materials for lithium ion batteries 1,2,3 1,2,4 1,2 1,2 1,2 Hui Shan • Yang Zhao • Xifei Li • Dongbin Xiong • Lei Dong • 1,2 1,2 1,2,4 Bo Yan • Dejun Li • Xueliang Sun Received: 1 March 2016 / Accepted: 16 April 2016 / Published online: 29 April 2016 Ó Springer Science+Business Media Dordrecht 2016 Abstract By shielding zinc stannate (ZTO, viz., performance. As a result, the resultant anode material Zn2SnO4) nanoparticles with reduced graphene oxide shows high reversible capacity, superior rate capacity and (RGO) as well as multi-wall carbon nanotubes long-running cycle performance for lithium ion batteries (MWCNTs), we have successfully created ZTO/RGO/ (LIBs). For instance, a excellent reversible capacity of MWCNTs composites via a facile hydrothermal process. In 915.9 mAh g-1 was obtained at the current density of the designed hybrid nanostructure, acting as the strut and 100 mA g-1 after 340 cycles. Our study demonstrates bridge to open the graphene sheets, 3D RGO/MWCNT nets significant potential of ZTO/RGO/MWCNTs as anode not only tackle the problem of volume expansion and the materials for LIBs. aggregation of ZTO nanoparticles, but also maintain the Graphical Abstract integration of anode materials for high electrochemical Hui Shan and Yang Zhao these authors have contributed equally. & Xifei Li 1 Energy & Materials Engineering Centre, College of Physics xfl[email protected] and Materials Science, Tianjin Normal University, Tianjin 300387, China & Dejun Li [email protected] 2 Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, Tianjin 300387, & Xueliang Sun China [email protected] 123 852 J Appl Electrochem (2016) 46:851–860 Keywords Zn2SnO4 nanoparticles Á Reduced graphene the porous structures and adsorption properties of MOFs oxide Á Carbon nanotubes Á Lithium ion batteries Á Anode [15].
    [Show full text]
  • Molecular Understanding of Electrochemical–Mechanical Responses in Carbon-Coated Silicon Nanotubes During Lithiation
    nanomaterials Article Molecular Understanding of Electrochemical–Mechanical Responses in Carbon-Coated Silicon Nanotubes during Lithiation Chen Feng 1, Shiyuan Liu 1 , Junjie Li 2, Maoyuan Li 3 , Siyi Cheng 4, Chen Chen 1, Tielin Shi 1 and Zirong Tang 1,* 1 State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; [email protected] (C.F.); [email protected] (S.L.); [email protected] (C.C.); [email protected] (T.S.) 2 Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; [email protected] 3 State Key Laboratory of Materials Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; [email protected] 4 School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China; [email protected] * Correspondence: [email protected] Abstract: Carbon-coated silicon nanotube (SiNT@CNT) anodes show tremendous potential in high- performance lithium ion batteries (LIBs). Unfortunately, to realize the commercial application, it is still required to further optimize the structural design for better durability and safety. Here, the electrochemical and mechanical evolution in lithiated SiNT@CNT nanohybrids are investigated using large-scale atomistic simulations. More importantly, the lithiation responses of SiNW@CNT Citation: Feng, C.; Liu, S.; nanohybrids are also investigated in the same simulation conditions as references. The simulations Li, J.; Li, M.; Cheng, S.; Chen, C.; quantitatively reveal that the inner hole of the SiNT alleviates the compressive stress concentration Shi, T.; Tang, Z.
    [Show full text]
  • Nanopurification of Silicon from 84% to 99.999% Purity with a Simple and Scalable Process
    Nanopurification of silicon from 84% to 99.999% purity with a simple and scalable process Linqi Zonga, Bin Zhua, Zhenda Lub, Yingling Tana, Yan Jina, Nian Liub, Yue Hua, Shuai Gua, Jia Zhua,1, and Yi Cuib,c,1 aNational Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; bDepartment of Materials Science and Engineering, Stanford University, Stanford, CA 94305; and cStanford Institute for Materials and Energy Sciences, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025 Edited by Charles M. Lieber, Harvard University, Cambridge, MA, and approved September 18, 2015 (received for review July 2, 2015) Silicon, with its great abundance and mature infrastructure, is a need from low-grade silicon is of high energy consumption and foundational material for a range of applications, such as elec- heavy pollution. Purification processes of Si typically involve the tronics, sensors, solar cells, batteries, and thermoelectrics. These conversion of Si into volatile liquids (such as trichlorosilane or Si applications rely on the purification of Si to different levels. Recently, tetrachloride) or gaseous silane (30). The compounds are then it has been shown that nanosized silicon can offer additional separated by a distillation and transformed into high-purity Si by advantages, such as enhanced mechanical properties, significant either a redox reaction or chemical decomposition at high absorption enhancement, and reduced thermal conductivity. How- temperatures. Additional steps are needed to obtain the nano- ever, current processes to produce and purify Si are complex, ex- structures of Si by either top-down methods, such as lithography, pensive, and energy-intensive.
    [Show full text]
  • Silicon Nanowires for Energy Generation and Storage
    SILICON NANOWIRES FOR ENERGY GENERATION AND STORAGE Memoria presentada por: Sergio Pinilla Yanguas Para optar al grado de Doctor en Ciencias Físicas por la Universidad Autónoma de Madrid con Mención Internacional Directora: Carmen Morant Zacarés Facultad de Ciencias Departamento de Física Aplicada Junio 2017 Agradecimientos Al presentar una tesis doctoral pareciera que se tratara del resultado de un trabajo estrictamente individual, sin embargo, no es así. Aunque el esfuerzo para el doctorando puede, en ocasiones, resultar abrumador, es también cierto que ese trabajo se ha ido nutriendo de conocimientos y experiencias transmitidas, tanto de manera formal como informal, por buen número de colegas y amigos. Por ello, considero que es de justicia señalar a aquellas personas que, de una u otra forma, han contribuido a este trabajo a lo largo de cinco años. Entre ellas, en primer lugar, se encuentran mis dos directores de tesis, Eduardo Elizalde y Carmen Morant. Desde que comencé el doctorado no he parado de escuchar historias de tensas relaciones entre directores y doctorandos que transforman la tesis en poco menos que una tortura. Pues bien, mi experiencia ha sido la contraria. Desde que comenzara esta andanza, ellos han mostrado siempre una gran confianza en mi trabajo, dándome mucha libertad, aunque siempre pendientes de mi trabajo, aportando a él su experimentada visión y conocimiento. Creo haber crecido mucho como investigador con vosotros y espero y deseo que en el futuro esta relación se mantenga tanto dentro como fuera del laboratorio. Probably, one of the most important experiences in my PhD, has been my stay in the Trinity College of Dublin.
    [Show full text]
  • (C:\\Users\\\314\306\262\323
    ABSTRACT TANG, CAN. Lithium Ion Battery Anodes Produced from Densified, Silicon Coated, Carbon Nanotube Arrays. (Under the direction of Dr. Philip Bradford.) The increasing demand in energy storage for portable devices and electric vehicles requires the further development of lithium ion batteries. In this study, lithium ion battery anodes were produced from densified, silicon coated, carbon nanotube arrays. One of the goals of this study was to uniformly coat silicon onto individual carbon nanotubes. Carbon nanotube arrays were used to compensate for the volume expansion of silicon while providing the anode with sufficient electrical conductivity. A chemical vapor deposition system was built to synthesize carbon nanotube arrays and deposit the silicon coating. Baseline anodes of carbon nanotube arrays and silicon coated carbon nanotube array anodes were assembled and tested in coin cells without binder or a current collector metal foil. SEM, TEM, XRD and Raman spectroscopy confirmed relatively uniform crystalline silicon nano-particles were coated throughout the carbon nanotube arrays. The results showed that carbon nanotube array anodes with silicon coating had improved capacity as well as coulombic efficiency. Silicon coated post-treated carbon nanotube array anodes showed improved cycling performance with about twice capacity retention compared to the composite anodes produce with as-grown, pristine carbon nanotube arrays. After composite structure optimization, composite carbon nanotube array (chlorine+30%Si+carbon) anodes exhibited a charge capacity of 1360mAh/g for the first cycle with about 73% capacity retention on the 20 th cycle. Lithium Ion Battery Anodes Produced from Densified, Silicon Coated, Carbon Nanotube Arrays by Can Tang A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science Textile Engineering Raleigh, North Carolina 2012 APPROVED BY: _______________________________ ______________________________ Dr.
    [Show full text]
  • The Capacity and Durability of Amorphous Silicon Nanotube Thin Film Anode for Lithium Ion Battery Applications Maria L
    A124 ECS Electrochemistry Letters, 4 (10) A124-A128 (2015) The Capacity and Durability of Amorphous Silicon Nanotube Thin Film Anode for Lithium Ion Battery Applications Maria L. Carreon, Arjun K. Thapa,∗ Jacek B. Jasinski, and Mahendra K. Sunkara∗,z Department of Chemical Engineering and Conn Center for Renewable Energy Research, University of Louisville, Louisville, Kentucky 40292, USA In this communication, we report that a silicon nanotube thin film electrode with 0.6 mg loading exhibited an initial discharge capacity of 4766 mAh g−1 and retained about 3400 mAh g−1 after 20 cycles at 100 mA g−1 rate. The silicon nanotube thin film samples with thicknesses ranging from 10–28 microns were prepared using silicon deposition on bulk produced zinc oxide nanowire films and subsequent removal of zinc oxide cores. The developed silicon nanostructures exhibit tubular geometry with both open ends. The nanotubes with thin walls are shown to accommodate large volume changes with lithiation and exhibit stable capacity retention. The presence of hydrogenated nanocrystalline silicon (nc-Si:H) is shown to be essential for the silicon nanotube thin film performance for lithium ion battery applications. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.0031510eel] All rights reserved. Manuscript submitted March 13, 2015; revised manuscript received July 22, 2015. Published July 30, 2015.
    [Show full text]
  • One-Dimensional Nanostructure Growth in PAA
    +D=FJAH ! One-dimensional nanostructure growth in PAA The 1D nanostructure synthesis is of high interest in many domains, since a lot of new properties can be revealed at this scale of matter. Some inherent challenges are however intimately related to this synthesis, namely the organisation, the handling and the con- tacting (in the case of electrical applications) of these nanostructures. In this chapter, we will introduce a method commonly used to easily organize the 1D nanostructures, as well as to make their handling and contacting easier. This method is the conned growth in nanometric-size tubular templates, which parallel pores receive the nanostructures like a mold. In that purpose, it is planned to use Porous Anodic Alumina (PAA) templates, already studied in the rst chapter. In a rst part we will set out a general denition of 1D nanostructures, explain their potential (and promising) applications and sum up the most promising devices reported in the literature hitherto. Then a section will be devoted to an overview of dierent synthesis techniques (including the one we used in this work to grow SiNWs and CNTs) and to the theoretical description of some growth mechanisms. In the section after we will introduce our experimental set up and discuss our results, before concluding this chapter. 3.1 Denitions and potential applications In the most general sense, the term "nanostructure" refers to any ensemble which at least one dimension is between 1 and 100 nm. Nowadays, advanced fabrication tech- niques allow to fabricate a wide variety of nanostructures, thus described as "articial", but of course Nature hasn't waited for human beings to exhibit ultra-small structures, with complex features, and equipped with natural ultra-sophisticated functionalities.
    [Show full text]