Dissertations / Theses on the topic 'Electrochemical energy storage and conversion'
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Chandrasekaran, Rajeswari. "Modeling of electrochemical energy storage and energy conversion devices." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37292.
Full textNavarrete, Algaba Laura. "New electrochemical cells for energy conversion and storage." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/78458.
Full textEn la presente tesis doctoral se han desarrollado materiales para su uso en celdas electroquímicas. Las celdas electroquímicas estudiadas, se podrían separar en dos grandes grupos: materiales de óxido sólido y sales ácidas. En el primer grupo, se optimizaron materiales para su uso como electrodos en pilas de combustible y electrolizadores, basados en electrolitos con conducción puramente iónica. Dentro de este grupo, se comprobó la influencia de dopar la perovskita Ba0.5Sr0.5Co0.8Fe0.2O3-d, con un 3% de Y, Zr y Sc en la posición B (ABO3-d). Esta optimización llevó a la reducción de la resistencia de polarización así como a una mejora de la estabilidad con el tiempo. Así mismo, se determinaron los mecanismos limitantes en la reacción de reducción de oxígeno, y se comprobó la influencia de la presencia de CO2 en condiciones de operación. El La2NiO4+d perteneciente a la serie de Ruddlesden-Popper, es un conductor mixto de iones oxígeno y electrones. Éste, fue dopado tanto en la posición del La (con Nd y Pr) como en la posición del Ni (con Co). Los dopantes introducidos además de producir cambios estructurales, provocaron mejoras en el rendimiento de la celda, reduciendo para alguno de ellos, como el La1.5Pr0.5Ni0.8Co0.2O4+d, en casi un orden de magnitud la resistencia de polarización del electrodo de referencia (La2NiO4+d). De la misma manera, se optimizaron las propiedades del electrodo basado en el conductor electrónico puro La0.8Sr0.2MnO3-d (LSM). La adición de una segunda fase, con conductividad iónica, permitió aumentar los puntos triples (TPB) en los que la reacción de reducción de oxígeno tiene lugar y reducir la resistencia de polarización. Con el fin de mejorar la reacción de reducción de oxígeno, se estudió la adición de nanocatalizadores mediante la técnica de infiltración. Los diferentes óxidos infiltrados produjeron el cambio de las propiedades electroquímicas del electrodo, siendo el óxido de praseodimio el catalizador que consiguió disminuir en dos órdenes de magnitud la resistencia de polarización del composite no infiltrado. De la misma manera, la mejora de la eficiencia del electrodo infiltrado con Pr, mejoró los resultados de la celda electroquímica trabajando como pila (mayores densidades de potencia) y como electrolizador (menores voltajes). En lo que respecta a los materiales seleccionados para su uso como electrodos en electrolitos con conductividad protónica, se optimizó la eficiencia del cátodo basado en LSM, mediante el uso de una segunda fase conductora protónica (La5.5WO12-d) y variando la temperatura de sinterización del electrodo. Finalmente, se mejoró la actividad catalítica mediante la infiltración de nanopartículas de ceria dopada con samario, produciendo mayores densidades de corriente de la pila de combustible. Los materiales pertenecientes a la serie de Ruddlesden-Popper y usados para cátodos en pilas iónicas, fueron empleados también para cátodos en pilas protónicas. Después de comprobar que el material electrolítico (LWO) era compatible con los compuestos de la serie de Ruddlesden-Popper, se estudió la influencia de la temperatura de sinterización de los electrodos en el rendimiento, así como de la composición de la atmosfera de aire (seca, H2O y D2O). Finalmente, se diseñó y optimizó las celdas electroquímicas basadas en sales ácidas (CsH2PO4). En este sentido, se estudiaron diferentes configuraciones de celda, que permitieran obtener un electrolito denso con el menor espesor posible y unos electrodos activos a la reacción de reducción/oxidación de hidrógeno. Se consiguió reducir el espesor del electrolito soportando la celda en discos de acero y níquel porosos. Se añadió una resina tipo epoxi al material electrolítico para aumentar sus propiedades mecánicas. De la misma manera, se cambió la configuración de los electrodos pasando por conductores electrónicos puros a electrodos compuestos por conductores
En la present tesis doctoral es van desenvolupar materials per al seu ús en cel·les electroquímiques. Les cel·les electroquímiques estudiades poden ser dividides en dos grans grups: materials d'òxid sòlid i sals àcides. En el primer grup, es van optimitzar materials per al seu ús com a elèctrodes en piles de combustible i electrolitzadors, basats en electròlits amb conducció purament iònica. Dins d'este grup, es va comprovar la influència de dopar la perovskita Ba0.5Sr0.5Co0.8Fe0.2O3-d amb un 3% de Y, Zr i Sc en la posició B (ABO3-d;). Esta optimització va portar a la reducció de la resistència de polarització així com a una millora de l'estabilitat amb el temps. Així mateix, es van determinar els mecanismes limitants en la reacció de reducció d'oxigen, i es va comprovar la influència de la presència de CO2 en condicions d'operació. El La2NiO4+d pertanyent a la sèrie de Ruddlesden-Popper, és un conductor mixt d'ions oxigen i electrons. Este, va ser dopat tant en la posició del La (amb Nd i Pr) com en la posició del Ni (amb Co). Els dopants introduïts a més de produir canvis estructurals, van provocar millores en el rendiment de la cel·la, reduint per a algun d'ells, com el La1.5Pr0.5Ni0.8Co0.2O4+d, en quasi un ordre de magnitud la resistència de polarització de l'elèctrode de referència (La2NiO4+d). De la mateixa manera, es van optimitzar les propietats de l'elèctrode basat en el conductor electrònic pur La0.8Sr0.2MnO3-d (LSM). L'addició d'una segona fase, amb conductivitat iònica, va permetre augmentar els punts triples (TPB), en els que la reacció de reducció d'oxigen té lloc, i reduir la resistència de polarització. A fi de millorar la reacció de reducció d'oxigen, es va estudiar l'adició de nanocatalitzadors per mitjà de la tècnica d'infiltració. Els diferents òxids infiltrats van produir el canvi de les propietats electroquímiques de l'elèctrode, sent l'òxid de praseodimi el catalitzador que va aconseguir disminuir en dos ordres de magnitud la resistència de polarització del composite no infiltrat. De la mateixa manera, la millora de l'eficiència de l'elèctrode infiltrat amb Pr, va millorar els resultats de la cel·la electroquímica treballant com a pila (majors densitats de potència) i com a electrolitzador (menors voltatges). Pel que fa als materials seleccionats per al seu ús com a elèctrodes en electròlits amb conductivitat protònica, es va optimitzar l'eficiència del càtode basat en LSM, per mitjà de l'ús d'una segona fase conductora protònica (La5.5WO12-d;) i variant la temperatura de sinterització de l'elèctrode. Finalment, es va millorar l'activitat catalítica mitjançant la infiltració de nanopartícules de ceria dopada amb samari, produint majors densitats de corrent de la pila de combustible. Els materials pertanyents a la sèrie de Ruddlesden-Popper i usats per a càtodes en piles iòniques, van ser empleats també per a càtodes en piles protòniques. Després de comprovar que el material electrolític (LWO) era compatible amb els compostos de la sèrie de Ruddlesden-Popper, es va estudiar la influència de la temperatura de sinterització dels elèctrodes en el rendiment, així com de la composició de l'atmosfera d'aire (seca, H2O i D2O). Finalment, es van dissenyar i optimitzar les cel·les electroquímiques basades en sals àcides (CsH2PO4). En este sentit, es van estudiar diferents configuracions de cel·la, que permeteren obtindre un electròlit dens amb el menor espessor possible i uns elèctrodes actius a la reacció de reducció/oxidació d'hidrogen. Es va aconseguir reduir l'espessor de l'electròlit suportant la cel·la en discos d'acer i níquel porosos. Es va afegir una resina tipus epoxi al material electrolític per a augmentar les seues propietats mecàniques. De la mateixa manera, es va canviar la configuració dels elèctrodes passant per conductors electrònics purs a elèctrodes compostos per conductors protònics
Navarrete Algaba, L. (2017). New electrochemical cells for energy conversion and storage [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/78458
TESIS
Jonas, Ncumisa Prudence. "Electrochemical energy conversion using metal hydrides hydrogen storage materials." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2992_1361369645.
Full textMetal hydrides hydrogen storage materials have the ability to reversibly absorb and release large amounts of hydrogen at low temperature and pressure. In this study, metal hydride materialsemployed as negative electrodes in Ni-MH batteries are investigated. Attention is on AB5 alloys due to their intermediate thermodynamic properties. However, AB5 alloys a have 
tendency of forming oxide film on their surface which inhibits hydrogen dissociation and penetration into interstitial sites leading to reduced capacity. To redeem this, the materials were micro-encapsulated by electroless deposition with immersion in Pd and Pt baths. PGMs were found to increase activation, electrochemical activity and H2 sorption kinetics of the MH alloys. Between the two catalysts the one which displayed better performance was chosen. The materials were characterized by X-ray difractommetry, and the alloys presented hexagonal CaCu5 &ndash
type 
structure of symmetry P6/mmm. No extra phases were found, all the modified electrodes displayed the same behavior as the parent material. No shift or change in peaks which corresponded to Pd or Pt were observed. Scanning Electron Microscopy showed surface morphology of the materials modified with Pd and Pt particles, the effect of using different reducing agents (i.e., N2H4 and NaH2PO2), and alloys functionalized with &gamma
-aminosopropyltrietheosilane solution prior to Pd deposition. From all the surface modified alloys, Pt and Pd particles were observed on the 
surface of the AB5 alloys. Surface modification without pre-functionalization had non-uniform coatings, but the prefunctionalized exhibited more uniform coatings. Energy dispersive X-ray Spectroscopy and Atomic Absorption Spectroscopy determined loading of the Pt and Pd on the surface of all the alloys, and the results were as follows: EDS ( Pt 13.41 and Pd 31.08wt%), AAS (Pt 0.11 and Pd 0.78wt%). Checking effect of using different reducing agents N2H4 and NaH2PO2 for electroless Pd plating the results were as follows: EDS (AB5_N2H4_Pd- 7.57 and AB5_NaH2PO2_Pd- 31.08wt%), AAS (AB5_N2H4_Pd- 11.27 and AB5_NaH2PO2_Pd- 0.78wt%). For the AB5 alloys pre-functionalized with &gamma
-APTES, the results were: EDS (10.24wt%) and AAS (0.34wt%). Electrochemical characterization was carried out by charge/discharge cycling controlled via potential to test the AB5 alloy. Overpotential for unmodified, Pt and Pd modified 
electrodes were -1.1V, -1.24V, and -1.60V, respectively. Both modified electrodes showed discharge overpotentials at lower values implying higher specific power for the battery in comparison with the unmodified electrodes. However, Pd electrode exhibited higher specific power than Pt. To check the effect of the reducing agent the results were as follows: AB5_ N2H4_Pd (0.4V) and AB5_NaH2PO2_Pd (-0.2V), sodium hypophosphite based alloy showing lower overpotential values, implying it had higher specific power than hydrazine based bath. Alloy prefunctionalized with &gamma
-APTES, the overpotential was (0.28V), which was higher than -0.2V of the alloy without pre-functionalization, which means pre-functionalization with &gamma
-APTES did not improve the performance of the alloy electrode. Polarization resistance of the electrodes was investigated with Electrochemical Impedance Spectroscopy. The unmodified alloy showed high resistance of 
21.6884 while, both Pt and Pd modified electrodes exhibited decrease 14.7397 and 12.1061 respectively, showing increase in charge transfer for the modified electrodes. Investigating the effect of the reducing agent, the alloys exhibited the following results: (N2H4 97.8619 and NaH2PO2 12.1061) based bath. Alloy pre-functionalized with &gamma
-APTES displayed the 
resistance of 9.3128. Cyclic Voltammetry was also used to study the electrochemical activity of the alloy electrodes. The voltammograms obtained displayed the anodic current peak at -0.64V 
o -0.65V for the Pt and Pd modified electrodes, respectively. Furthermore, the electrode which was not coated with Pt or Pd the current peak occurred at -0.59V. The Pd and Pt coated 
alloy electrodes represented lower discharge overpotentials, which are important to improve the battery performance. Similar results were also observed with alloy electrodes Pd modified 
using N2H4 (-0.64V) and NaH2PO2 (-0.65V). For the electrode modified with and without &gamma
-APTES the over potentials were the same (-0.65V). PGM deposition has shown to significantly 
improve activation and hydrogen sorption performance and increased the electro-catalytic activity of these alloy electrodes. Modified electrodes gave better performance than the unmodified 
electrodes. As a result, Pd was chosen as the better catalyst for the modification of AB5 alloy. Based on the results, it was concluded that Pd electroless plated using NaH2PO2 reducing agent 
had better performance than electroless plating using N2H4 as the reducing agent. Alloy electrode pre-functionalized with &gamma
-APTES gave inconsistent results, and this phenomenon needs to 
be further investigated. In conclusion, the alloy modified with Pd employing NaH2PO2 based electroless plating bath exhibited consistent results, and was found to be suitable candidate for 
use in Ni-MH batteries.
Aaronson, Barak D. B. "High resolution electrochemical imaging for energy conversion and storage applications." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/78415/.
Full textDiLeo, Roberta A. "Nanomaterial synthesis and characterization for energy storage and conversion devices /." Online version of thesis, 2008. http://hdl.handle.net/1850/7367.
Full textSheehan, Margaret K. "Enhanced Performance in Electrochemical Energy Storage and Conversion via Carbon-Integrated Nanostructures." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107261.
Full textElectrochemical energy storage and conversion applications benefit from the integration of nanostructures into the devices, as they have many more active sites per gram which enables excellent mass utilization of the active species. By controlling the surface of fuel cell catalysts, higher activity and efficiency can be achieved as compared to the bulk counterpart, with multiple catalyst facets of varying activity and efficiency. Nanostructured electrochemical capacitors have enhanced electrolyte diffusion over the surface of the electrode, facilitating high rate capability. Nanostructured materials for energy storage and conversion devices, such as electrochemical capacitors and proton exchange membrane fuel cells, can perform even better with the incorporation of carbon. High surface area carbon can enhance the activity of electrochemical capacitors by improving the conductivity of the electrode and/or enhancing the double layer capacitance. Carbon supports for fuel cell catalysts enable proper dispersion of active material without sacrificing conductivity. The work reported in this thesis is aimed toward improving the performance of electrochemical energy storage and conversion devices through novel incorporation of carbon. Carbon was first used to enhance the performance of electrocatalysts. By wrapping fuel cell catalysts in a porous carbon shell, the activity was increased over its bare and CNT-supported counterparts. The carbon shell synthetic method reported here is a good route to the production of a conductive host for Pd electrocatalysts with good contact and in one step with the formation of the Pd nanoparticles. Carbon was also used to enhance the performance of pseudocapacitors, first by incorporating it into the precursor spray solution in the generation of mesoporous metal oxides and then as a metal-organic framework-derived carbon host with dispersed electrochemically active metal oxides. A carbon network was generated from the pyrolysis of pore directing agents during the decomposition of precursor metal nitrates in the generation of mesoporous manganese oxides in a modified spray pyrolysis approach. The addition of Super P to the precursor spray solution further enhanced the conductivity of the material, enabling the formation of high-performing pseudocapacitors. Lastly, nitrogen-doped carbon cubes produced from thermally-treated parent ZIF-8 cubes were tested as electrochemical capacitors and found to have higher specific capacitance than the nitrogen-doped carbon generated from the parent ZIF-8 rhombic dodecahedra. ZIF-67 cubes were then thermally treated to yield cubic nitrogen-doped carbon hosts for the generated cobalt nanoparticles. Once the cobalt particles were oxidized, the cobalt oxide/carbon hybrid structure exhibited the best pseudocapacitive performance of the ZIF-derived carbon materials tested, exhibiting high specific capacitance and good capacitance retention with increased scan rates and prolonged cycling. Each of the materials tested for electrochemical energy storage and conversion saw an enhancement in performance with the addition of carbon. The results reported here illustrate the importance of carbon in electrochemical cells and the importance of continuing research to modify and improve the methods for carbon production and integration
Thesis (PhD) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
McCulloch, William David. "Electrochemical Energy Conversion and Storage through Solar Redox Flow and Superoxide Batteries." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524054086338847.
Full textFalola, Bamidele Daniel. "TRANSITION METAL COATINGS FOR ENERGY CONVERSION AND STORAGE; ELECTROCHEMICAL AND HIGH TEMPERATURE APPLICATIONS." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/dissertations/1354.
Full textKim, Il Tae. "Carbon-based magnetic nanohybrid materials for polymer composites and electrochemical energy storage and conversion." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45876.
Full textLee, Seung Woo Ph D. Massachusetts Institute of Technology. "Design of electrode for electrochemical energy storage and conversion devices using multiwall carbon nanotubes." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59878.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
All-multiwall carbon nanotube (MWNT) thin films are created by layer-by-layer (LbL) assembly of surface functionalized MWNTs. Negatively and positively charged MWNTs were prepared by surface functionalization, allowing the incorporation of MWNTs into highly tunable thin films via the LbL technique. The pH dependent surface charge on the MWNTs gives this system the unique characteristics of LbL assembly of weak polyelectrolytes, controlling thickness and morphology with assembly pH conditions. We demonstrate that these MWNT thin films have randomly oriented interpenetrating network structure with well developed nanopores using SEM, which is an ideal structure of functional materials for various applications. LbL-MWNT electrodes show high electronic conductivity in comparison with polymer composites with single wall nanotubes, and high capacitive behavior in aqueous electrolyte with precise control of capacity. Of significance, additive-free LbL-MWNT electrodes with thicknesses of several microns can deliver high energy density (200 Wh/kg) at an exceptionally high power of 100 kW/kg in lithium nonaqueous cells. Utilizing the redox reactions on the surface functional groups in a wide voltage window (1.5 - 4.5 V vs. lithium) in nonaqueous electrolytes, asymmetric electrochemical capacitors consisting of LbL-MWNT and either lithium or a lithium titanium oxide negative electrode exhibit gravimetric energy density -5 times higher than conventional electrochemical capacitors with comparable gravimetric power and cycle life. Thin-film LbL-MWNT electrodes could potentially lead to breakthrough power sources for microsystems and flexible electronic devices such as smart cards and ebook readers, while thicker LbL-MWNT electrodes could expand the application of electrochemical capacitors into heavy vehicle and industrial systems, where the ability to deliver high energy at high power will be an enabling technological development. Furthermore, nanoscale pseuduocapactive oxides and electrocatalysts were incorporated into LbL-MWNT electrodes for energy storage and conversion. Inorganic oxides such as MnO2 and RuO2 are incorporated to increase volumetric capacitance in LbLMWNT electrodes using electroless deposition and square wave pulse potential deposition methods. Preliminary results show that we can increase volumetric capacitance of LbLMWNT/ MnO2 and LbL-MWNT/RuO2 composite up to 1000 F/cm3 in aqueous electrolytes. In addition, Pt and Pt/Ru alloy electrocatalysts are introduced into LbL-MWNT electrodes using square wave pulse potential deposition, which show higher CO and methanol oxidation activities. Tailored incorporation of metal and oxide nanoparticles into LbLMWNT electrodes by square wave pulse potential opens a new strategy for novel energy storage and conversion electrodes with superior electrochemical properties.
by Seung Woo Lee.
Ph.D.
Farmand, Maryam. "X-ray Absorption Spectroscopy Characterization of Electrochemical Processes in Renewable Energy Storage and Conversion Devices." Thesis, The George Washington University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3557518.
Full textThe development of better energy conversion and storage devices, such as fuel cells and batteries, is crucial for reduction of our global carbon footprint and improving the quality of the air we breathe. However, both of these technologies face important challenges. The development of lower cost and better electrode materials, which are more durable and allow more control over the electrochemical reactions occurring at the electrode/electrolyte interface, is perhaps most important for meeting these challenges. Hence, full characterization of the electrochemical processes that occur at the electrodes is vital for intelligent design of more energy efficient electrodes.
X-ray absorption spectroscopy (XAS) is a short-range order, element specific technique that can be utilized to probe the processes occurring at operating electrode surfaces, as well for studying the amorphous materials and nano-particles making up the electrodes. It has been increasingly used in recent years to study fuel cell catalysts through application of the Δ&mgr; XANES technique, in combination with the more traditional X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) techniques. The Δ&mgr; XANES data analysis technique, previously developed and applied to heterogeneous catalysts and fuel cell electrocatalysts by the GWU group, was extended in this work to provide for the first time space resolved adsorbate coverages on both electrodes of a direct methanol fuel cell. Even more importantly, the Δ&mgr; technique was applied for the first time to battery relevant materials, where bulk properties such as the oxidation state and local geometry of a cathode are followed.
Chen, Po-Yen Ph D. Massachusetts Institute of Technology. "M13 virus-enabled assembly of 3D nanostructured composites : synthesis and applications in solar energy conversion and electrochemical energy storage devices." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98704.
Full textCataloged from PDF version of thesis. Vita.
Includes bibliographical references.
We live in an age where our society faces the great challenge of generating, storing and transporting energy in responsible ways that minimize impact to the environment. Significant effort has been spent to develop new technologies capable of (1) efficiently converting renewable energy into usable electricity, (2) storing energy into high performance energy storage devices, and (3) fabricating advanced energy conversion and storage devices using environmentally benign technologies. One of the approaches is to genetically engineer M13 bacteriophage (M13 virus) to display proteins with specific functionalities, which allow the synthesis and organization of hybrid materials in environmentally friendly manners. The primary goal of my Ph.D. thesis has been to develop M13 virus-enabled processes for building the electrodes of advanced energy conversion and energy storage devices, including dye-sensitized solar cells (DSCs), electrochemical capacitors, and perovskite hybrid solar cells (PSCs). In order to fabricate nanostructures for the DSC photoanodes, the M13 viruses were crosslinked into a virus hydrogel that served as a multifunctional 3D scaffold capable of binding gold nanoparticles (AuNPs) to the virus proteins. The AuNP-virus hydrogel was encapsulated in titanium dioxide (TiO₂) to produce a plasmon-enhanced nanowire (NW)-based DSC photoanode that enabled a power conversion efficiency (PCE) of 8.46%. A theoretical model was developed that predicted the experimentally observed trends of plasmon-enhancement. Furthermore, to optimize the surface-to-volume ratio of the photoanodes to maximize PCE, a tunable fabrication process used individual free-floating M13 virus as the template for TiO₂ NWs, and the assynthesized NWs were blended with sacrificial polymer to control the film porosity. The optimized semiconducting mesoporous networks were used as photoanodes in both DSCs and PSCs, and the effects of surface morphology on the photovoltaic properties was experimentally investigated. In order to construct the electrodes of electrochemical capacitors, M13 viruses were genetically programmed to bind single-walled carbon nanotubes (SWNTs) in a controlled fashion by aligning SWNTs along the length of the phage without aggregation. The SWNTs-virus complexes were used as the basis for the formation of crosslinked virus hydrogel scaffolds for the fabrication of porous 3D polyaniline (PANI) nanostructures. The PANI-coated SWNT nanocomposites further improved the electrical conductivity and electrochemical activity of thin films. In addition, by using a fog generator to deliver the crosslinker solution, larger-area virusbased hydrogels were fabricated for versatile material coatings, including PANI, MnOx, Ni, and Ni-MnOx. Lastly, an environmentally-responsible process to fabricate efficient PSCs was developed that recycled lead content from discarded car batteries. Perovskite films, assembled using materials sourced from either recycled battery materials or high-purity commercial reagents, showed the same material characterizations and the identical photovoltaic performance, indicating the practical feasibility of recycling car batteries for lead-based PSCs.
by Po-Yen Chen.
Ph. D.
Hildenbrand, Claudia. "Nanostructured carbons from cellulose-derivative-based aerogels for electrochemical energy storage and conversion : evaluation as EDLC electrode material." Paris, ENMP, 2010. http://pastel.archives-ouvertes.fr/pastel-00547497.
Full textNanostructured carbons are widely used in electrochemical energy storage and conversion devices, e. G. As electrode material for fuel cells, batteries, or still EDLCs (Electric Double Layer Capacitor). The carbon structure and surface chemistry are crucial parameters and consequently need to be adjusted to the specific application's requirements. This PhD thesis has aimed at developing a new family of nanostructured carbons: aerogels from renewable organic sol-gel precursors, i. E. Pyrolyzed cellulose-acetate-based aerogels. Sol-gel synthesis parameters and drying conditions of the organic gel, as well as pyrolysis parameters (particularly the influence of the sol composition, the type of catalyst used in the sol-gel synthesis step, pyrolysis temperature, and atmosphere) have been varied systematically in order to generate a broad range of structurally different cellulose-acetate-based carbonaceous aerogels. Further, cellulose-acetate-based carbon aerogels have been exposed to different post-treatments (e. G. Introduction of oxygen and nitrogen-containing surface functional groups) to create cellulose-acetate-based carbon aerogels with different surface chemistries. Finally, the performance of these cellulose-acetate-based carbon aerogels has been analyzed as EDLC electrode material
Renman, Viktor. "Structural and Electrochemical Relations in Electrode Materials for Rechargeable Batteries." Doctoral thesis, Uppsala universitet, Strukturkemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-334078.
Full textHoffmann, Viola [Verfasser]. "Conductive advanced carbon materials from biomass for the application in energy storage and conversion technologies (Electrochemical Double-Layer Capacitors and Direct Carbon Fuel Cells) / Viola Hoffmann." Düren : Shaker, 2020. http://d-nb.info/1222396181/34.
Full textMalhotra, Jaskaran Singh. "Carbon materials from biomass for supercapacitors." Thesis, KTH, Tillämpad fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285494.
Full textDen snabba pyrolysanläggningen vid RISE - ETC, Piteå, producerar kolrika kol i bulk från olika källor till biomassa som råvara. Dessa interna tillverkade kolrika karaktärer uppgraderades via pyrolys samt kemisk aktivering med hjälp av KOH för att förbättra deras potential som ett elektrodmaterial för superkondensatorer. Kommersiellt aktivt kol (Merck) studerades och användes som en måttstock för att jämföra våra materials prestanda. Undersökningar med EDX visar berikning av kolinnehåll och mycket låga mängder föroreningar i material som framställts av träkol efter specifika behandlingar för uppgradering. Tvåelektrodmyntcellapparater med en vattenhaltig elektrolyt användes för att bestämma den elektrokemiska prestandan hos dessa material. Träkol efter KOH-aktivering visar en hög specifik kapacitans på ~ 105 Fg-1 vid 2 Ag-1 i galvanostatiska laddningsurladdningsmätningar som överträffade aktivt kol som användes i denna studie (~ 68 Fg-1 vid 2 Ag-1). Detta material testades under ett stort antal betingelser (strömtäthet från 0,1 Ag-1 till 10 Ag-1) och visade specifik kapacitans från ~ 90 Fg-1 (för 10 Ag-1) upp till ~ 118 Fg-1 (för 0,1 Ag-1). Trötthetstestning för > 20000 cykler visade en anmärkningsvärt hög retention (> 96%) av kapacitansen. För närvarande använder de flesta kommersiella superkondensatorer aktivt kolmaterial framställt av kokosnötskal som det aktiva elektrodmaterialet som inte är hemma i Sverige. I den här studien uppgraderar vi träkolor som produceras vid RISE - ETC från biomassakällor erhållna lokalt (Sverige och Skandinavien) och visar deras användbarhet som superkapacitorelektrodmaterial.
Pham, Truong Thuan Nguyen. "Multifunctional materials based on task-specific ionic liquids : from fundamental to next generation of hybrid electrochemical devices and artifical skin." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC218/document.
Full textIncreasing demand of energy requires massive investment for exploration and utilization of renewable energy sources in the energy balance. However, due to the intermittence of the current renewable sources, the generated electricity must be stored under other forms to correlate the fleeting production and the continuous consumption. Despite available commercialized systems, seeking for new materials and new approaches for resolving this problem is still matter of interest for scientific researches. Highlighted advancements have recently oriented the community towards the utilization of nanoscale materials for efficient energy storage and conversion. Although the advantages given by existing nanomaterials for diverse applications, especially in the energy field, their performance is still lower than theoretical purposes. Consequently, tailoring the physical-chemical properties at the molecular scale becomes crucial not only for boosting the activities of the existed materials but also for creating a new type of molecular entities for storing and releasing the energy. Accordingly, this PhD work aim to develop new family of materials based on ionic liquid that exhibits a multifunctionality towards energy applications. Our work is based on the knowhow in surface functionalization and material preparation by simple methods to build up electrochemical systems that can be utilized in various applications. Thus, this thesis will report different results obtained by following this direction and is composed of six chapters: Chapter 1 reports an overview of ionic liquid and polymeric ionic liquid. We propose to review the available literature on the redox-IL from solution to immobilized substrates. Through this chapter, we will achieve the following points: (1) Report the possible uses of ionic liquids in electrochemistry; (2) Discuss about the physical-chemical behaviors of these compounds in solution, (3) Show the immobilization of (Redox-active)–ionic liquids onto different substrates: from thin layer to polymer and (4) Highlight recent advances using polymeric ionic liquids for diverse applications. Chapter 2 will be devoted to different electrochemical assisted approaches for the immobilization of (redox)-ionic liquids to the electrode surface. We will focus on generating a thin layer and polymeric film based ionic liquid. Furthermore, the different characteristics of the new interfaces will be reported. Chapter 3 concentrates on the use of the polymer ionic liquid modified electrodes as emerging catalyst and as template for the generation of hybrid materials towards activation of small molecules. Chapter 4 studies the reactivity at micro/nanometer scale of diverse materials, including single layer graphene, polymeric redox – ionic liquid, using the scanning electrochemical microscopy (SECM). Chapter 5 reports the potential applications of redox ionic liquid and focus on providing the preliminary results towards the fabrication of flexible substrates with interesting functionalities: possibility to convert the friction to electricity and energy storage by using polymeric redox ionic liquids. These studies open a new opportunity to elaborate flexible, wearable and implantable devices. Finally, some concluding remarks are given to summarize different results obtained in the previous chapters. Besides, different perspectives will be given by using ionic liquid as main material for developing different energy storage and conversion systems
Chin, Timothy Edward. "Electrochemical to mechanical energy conversion." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/63015.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
Electrode materials for rechargeable lithium ion batteries are well-known to undergo significant dimensional changes during lithium-ion insertion and extraction. In the battery community, this has often been looked upon negatively as a degradation mechanism. However, the crystallographic strains are large enough to warrant investigation for use as actuators. Lithium battery electrode materials lend themselves to two separate types of actuators. On one hand, intercalation oxides and graphite provide moderate strains, on the order of a few percent, with moderate bandwidth (frequency). Lithium intercalation of graphite can achieve actuation energy densities of 6700 kJ m-3 with strains up to 6.7%. Intercalation oxides provide strains on the order of a couple percent, but allow for increased bandwidth. Using a conventional stacked electrode design, a cell consisting of lithium iron phosphate (LiFePO4) and carbon achieved 1.2% strain with a mechanical power output of 1000 W m 3 . Metals, on the other hand, provide colossal strains (hundreds of percent) upon lithium alloying, but do not cycle well. Instead, a self-amplifying device was designed to provide continuous, prolonged, one-way actuation over longer time scales. This was still able to achieve an energy density of 1700 kJ n 3, significantly greater than other actuation technologies such as shape-memory alloys and conducting polymers, with displacements approaching 10 mm from a 1 mm thick disc. Further, by using lithium metal as the counterelectrode in an electrochemical couple, these actuation devices can be selfpowered: mechanical energy and electrical energy can be extracted simultaneously.
by Timothy Edward Chin.
Ph.D.
Carney, Thomas J. Ph D. (Thomas Joseph) Massachusetts Institute of Technology. "Convection enhanced electrochemical energy storage." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120204.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 119-136).
Electrochemical energy storage will play a pivotal role in our society's energy future, providing vital services to the transportation, grid, and residential markets. Depending on the power and duration requirements of a specific application, numerous electrochemical technologies exist. For the majority of the markets, lithium-ion (Li-ion) batteries are the state-of-the-art technology owing to their good cycle life and high energy density and efficiency. Their widespread penetration, however, is limited by high production cost and inherent safety concerns. Understanding the solid-electrolyte interphase (SEI) which governs the performance and lifetime of these batteries is critical to developing the next generation Li-ion batteries. As an alternative to Li-ion, redox flow batteries store energy in solutions of electroactive species, which are housed in external tanks and pumped to a power-converting electroreactor. This configuration decouples power and energy, improving the safety and flexibility of the system, however, flow battery energy density is inherently lower than Li-ion and expensive ion-selective membranes are required for efficient operation. As a contrast to Li-ion and redox flow batteries, convection batteries harnesses the key benefits of Li-ion batteries and redox flow batteries while overcoming their individual limitations. By incorporating thick electrodes into the cell, the energy density is increased and the cost of the system is reduced. To overcome the diffusive losses in the thick electrodes, electrolyte is pumped through the electrodes, enabling uniform ion transport throughout the porous structure. However, thick electrodes can lead to large ohmic losses in the cell resulting in lower energy efficiency. In this thesis, I discuss my work on understanding the SEI in Li-ion batteries, highlighting the thermodynamics of its origin, characterization of its structure, and strategies for future development. I then detail my work understanding redox active molecules from molecule characterization and mechanistic generation to redox flow cell level engineering. Finally, I highlight my work in the development of the convection battery technology explaining the synthesis of active materials, thick electrode design, and fabrication of the prototype convection cell architecture. Taken together, these projects highlight the theme of achieving low-cost electrochemical energy storage through various technical pathways.
by Thomas J. Carney.
Ph. D.
Rowlands, Stephen E. "Electrochemical supercapacitors for energy storage applications." Thesis, De Montfort University, 2002. http://hdl.handle.net/2086/4077.
Full textZuo, Yong. "Nanostructured Metal Sulfides for Electrochemical Energy Conversion." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/670925.
Full textEn esta tesis, se produjeron y optimizaron cuatro catalizadores nanoestructurados basados en Cu2S y SnS2 para mejorar su rendimiento hacia la conversión de energía electroquímica. El Capítulo 1 presentó una introducción general para explicar la motivación del tema de tesis. En el capítulo 2, las matrices de las nanovarillas de Cu2S se sintetizaron in situ sobre un sustrato de cobre metálico para la reacción electroquímica de evolución de oxígeno (OER). Se aplicaron herramientas de caracterización adecuadas para investigar la transformación en la operación OER, durante la cual las matrices iniciales de las nanovarillas Cu2S in situ cambió a nanohilos de CuO. En particular, el CuO derivado de Cu2S mostró un rendimiento de OER significativamente mejor cuando comparado al de CuO preparado mediante el recocido. En el capítulo 3, se detalló un proceso basado en una solución de inyección en caliente para producir nanoplacas ultrafinas SnS2 (NPL). Posteriormente, se cultivóPt en su superficie mediante la reducción in situ de una sal de Pt. Posteriormente se probó el rendimiento fotoelectroquímico (PEC) de los fotoanodes hacia la oxidación del agua. Los fotoanodes de SnS2-Pt optimizados proporcionaron densidades de fotocorriente significativamente más altas que el SnS2 desnudo (seis veces). Se analizó el efecto de Pt. En el capítulo 4, se informó una tinta molecular simple para cultivar capas de SnS2 nanoestructuradas directamente sobre sustratos conductores. Tales capas nanoestructuradas en FTO se caracterizaron por excelentes densidades de fotocorriente. Se utilize la misma estrategia para producir compuestos de grafeno-SnS2, recubrimientos ternarios SnS2-xSex, capas de SnSe2 de fase pura e incluso polvo de SnS2 a gran escala. En el capítulo 5, el SnS2 nanoestructurado con diferentes morfologías se probaron como ánodos LIB en primer lugar para encontrar que los NPL de SnS2 delgados proporcionaban el mayor rendimiento. Posteriormente, se desarrolló una estrategia de síntesis coloidal para cultivar los mismos NPL de SnS2 dentro de una matriz de g-C3N4 (CN) poroso y placas de grafito (GP) y se probaron para la aplicación LIB. Tales compuestos jerárquicos SnS2/CN/GP mostraron excelentes propiedades electroquímicas, lo que se atribuye a la sinergia creada entre los tres componentes como se investigó.
Nguyen, Olivier. "Towards a Li-ion photo-rechargeable battery." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS437.pdf.
Full textSunlight, as abundant clean source of energy, can alleviate the energy limits of batteries, while batteries can address photovoltaic intermittency. Conventional design of solar charging batteries involves the use of batteries and solar modules as two separate units connected by electric wires. In this work, we have studied another approach to harvest and store solar energy simultaneously into a single device, using a TiO2 bi-functional Li-ion battery photo-electrode. The apprehension of an electrode undergoing simultaneous light absorption and Li+ intercalation/extraction is very rich in terms of potentialities. At the same time, the various facets of the electrode evolution are very challenging to track and understand. Mesoporous TiO2 anatase thin film on FTO substrates are used as model electrodes to allow a careful control of the electrode architecture. They are prepared by combining the sol-gel chemistry with the dip-coating process, using the “evaporation induced self-assembly” (EISA) approach. In order to bring the proof of concept of the photo-recharge of the electrode, its electrochemical behaviour under illumination is studied using a Li-ion battery configuration. Photo-induced mechanisms and fate of photo-charges are investigated by studying the influence of the electrode architecture and of the electrolyte
Lin, Ziyin. "Functionalized graphene for energy storage and conversion." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51871.
Full textAltalhi, Amal A. "Energy conversion and storage via photoelectrochemical methods." Thesis, University of Hull, 2013. http://hydra.hull.ac.uk/resources/hull:16512.
Full textAnsovini, Davide. "Catalysis for sustainable energy conversion and storage." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/413468/.
Full textMellgren, Niklas. "Validated Modelling of Electrochemical Energy Storage Devices." Licentiate thesis, KTH, Mechanics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11052.
Full textThis thesis aims at formulating and validating models for electrochemical energy storage devices. More specifically, the devices under consideration are lithium ion batteries and polymer electrolyte fuel cells.
A model is formulated to describe an experimental cell setup consisting of a LixNi0.8Co0.15Al0.05O2 composite porous electrode with three porous separators and a reference electrode between a current collector and a pure Li planar electrode. The purpose of the study being the identification of possible degradation mechanisms in the cell, the model contains contact resistances between the electronic conductor and the intercalation particles of the porous electrode and between the current collector and the porous electrode. On the basis of this model formulation, an analytical solution is derived for the impedances between each pair of electrodes in the cell. The impedance formulation is used to analyse experimental data obtained for fresh and aged LixNi0.8Co0.15Al0.05O2 composite porous electrodes. Ageing scenarios are formulated based on experimental observations and related published electrochemical and material characterisation studies. A hybrid genetic optimisation technique is used to simultaneously fit the model to the impedance spectra of the fresh, and subsequently also to the aged, electrode at three states of charge. The parameter fitting results in good representations of the experimental impedance spectra by the fitted ones, with the fitted parameter values comparing well to literature values and supporting the assumed ageing scenario.
Furthermore, a steady state model for a polymer electrolyte fuel cell is studied under idealised conditions. The cell is assumed to be fed with reactant gases at sufficiently high stoichiometric rates to ensure uniform conditions everywhere in the flow fields such that only the physical phenomena in the porous backings, the porous electrodes and the polymer electrolyte membrane need to be considered. Emphasis is put on how spatially resolved porous electrodes and nonequilibrium water transport across the interface between the gas phase and the ionic conductor affect the model results for the performance of the cell. The future use of the model in higher dimensions and necessary steps towards its validation are briefly discussed.
Sakaushi, Ken. "On Design for Electrochemical Energy Storage Materials." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-132446.
Full textYang, Hao. "Graphene-based Materials for Electrochemical Energy Storage." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512095146429831.
Full textXuan, Jin, and 宣晋. "Numerical study of microfluidic electrochemical energy conversion system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46970708.
Full textYassin, Ali M. "Functional conjugated systems for energy conversion and storage." Angers, 2011. http://www.theses.fr/2011ANGE0080.
Full textThis work entitled « Functional Conjugated Systems for Energy Conversion and Storage » involves the design and synthesis of new classes of functional π-conjugated systems for photovoltaic conversion and the development of new microporous materials. After a general introduction to the structure and electronic properties of the major classes of conjugated systems and more particularly conjugated molecules used as donor material in organic solar cells (OSC), the second chapter describes the synthesis and study of a series of molecular donors obtained by grafting dicyanovinylene on three types of conjugated rigid blocks : carbazole, cyclopentadithiophene and dithienopyrrole (DTP). The evaluation of these systems in donor-acceptor bilayer heterojunction OSCs shows that the DTP leads to best results. A study of the evolution of the electronic properties, of a series of oligo-DTPs, with the chain length further confirms the interest of the donor block for low band gap conjugated systems. The next chapter deals with the synthesis of a series of conjugated molecules of donor-acceptor-donor (D-A-D) type, built around a core of isoindigo, and describes a first evaluation of their potential as donor materials in OSCs. The fourth chapter deals with the synthesis of a series of 3D molecules derived from the grafting of donor groupas on a quaterthiophene core with a quasi-tetrehedral geometry caused by steric effect, and examine the relationship between the structure of the molecules, the mobility of positive charges in these materials and their performance in OSCs. Finally the fift and last chapter describes the first steps towards the design and use of 3D conjugated molecules in order to develop new classes of electro-active materials by polymerization of microporous 3D molecular systems provided with reactive end groups
Tian, Hao. "Engineering carbon nanocomposites for energy storage and conversion." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59653.
Full textWang, Kuilong. "Surface science studies of electrochemical energy storage devices." Case Western Reserve University School of Graduate Studies / OhioLINK, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1056555985.
Full textPinto, Jonathan Hunder Dutra Gherard. "Conversor modular multinível aplicado a sistema híbrido de armazenamento de energia." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/6501.
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Este trabalho tem como contribuição o desenvolvimento de uma estratégia de equa-lização das tensões em um conversor multinível modular, como parte integrante de um sistema híbrido de armazenamento de energia. O conversor modular multinível realiza a conexão em série de módulos supercapacitores, o que possibilita aumentar a ten-são sem prejudicar a transferência rápida de energia. Em relação à outras topologias, este trabalho permite reduzir a quantidade, volume e massa do elemento magnético da estrutura do conversor. Um banco de baterias de íons de lítio também integra o sistema por intermédio de um conversor estático. Como é a fonte de maior densidade de energia, fornece a potência média requerida pelo carga. A associação com uma fonte de transferência rápida de energia permite aumentar o desempenho dinâmico, a eficiência energética e a vida útil da bateria. Com efeito, tem-se um sistema híbrido de armazenamento de energia que requer estratégias de gestão para múltiplas fontes de suprimento. Os resultados simulados considerando a estimativa da demanda de po-tência de um protótipo de veículo elétrico, são adequados e propiciam os fundamentos necessários para a construção de um protótipo.
This work is a contribution to develop a strategy equalization of tensions in a mo-dular multilevel converter as part of a hybrid system energy storage. The multilevel modular converter realizes the series connection of supercapacitor modules, which al-lows to increase the voltage without cause damages to the quick energy transfer. In relation to other topologies, it allows reduction of the quantity, volume and mass of the magnetic element of the converter structure. A lithium-ion battery bank also integrates the system via a voltage boost converter. This battery is the source of high energy density, which provides the average power required by the load. The association with a fast transfer power source allows for increased dynamic performance, energy efficiency and service life. In fact, there is a hybrid energy storage system that requires mana-gement strategies for multiple sources of supply. The simulated results were obtained considering the power demand estimation of an electric vehicle prototype.
Sagaidak, Iryna. "Bi-functional materials combining energy storage and energy conversion from sunlight." Thesis, Amiens, 2019. http://www.theses.fr/2019AMIE0025.
Full textThe problem of intermittent nature of solar energy is often addressed by the traditional coupling of the PV and battery units. Our more fundamental approach targets the development of materials able to combine solar energy conversion and storage at the molecular level. The 5 nm anatase TiO2 nanocrystals were synthesized in our group affording a quantitative photorecharge reaction by a sole contribution of illumination. Here, we present a study of the evolution of the optoelectronic properties and dynamics of charge transfer in TiO2 electrode using in situ / in operando experiments performed during the battery functioning (UV-visible, Mott-Schottky, fluorescence spectroscopy). The increase of the bandgap value and the rise of absorbance are observed upon lithium insertion into TiO2. A negative shift of the conduction band indicates a more oxidizing potential of the photogenerated holes in Li0.6TiO2 compared to TiO2. By analysis of the recombination processes in TiO2 upon lithium insertion, we established a competition of the ultra-fast (ps range) processes of direct recombination and charge transfer towards Ti3+ in Li0.6TiO2, potentially limiting the yield of the photorecharge reaction. This study was extended to other insertion materials typically used in lithium-ion batteries (Li4Ti5O12, LiCoO2, LiFePO4, MoO3, etc.). The measured band edge positions, band gap, charge carrier type and concentration were gathered into a database, based on which the fundamental evaluation of the possibility of the light-induced photorecharge was conducted. The first results of the photoelectrochemical study of chosen materials are also discussed
Oh, Sang Joon. "Electromagnetics of inertial energy storage systems with fast electromechanical energy conversion /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Full textWang, Huizhi, and 王慧至. "Electrochemical conversion of aluminum energy: energy efficiency, co-production concept and systemcharacteristics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B4697040X.
Full textTang, PengYi. "Semiconductor composite materials for energy storage and conversion applications." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/664734.
Full textThe energy originated from fossil fuels has enabled the remarkable advancement of civilization over the past century. However, fossil fuels are not infinite in supply and they are a source of increasing atmospheric carbon dioxide and the associated abominable environmental effects. Improving the efficiency of the energy storage devices and conversion of solar energy into hydrogen energy via water splitting are key technologies to tackle the serious energy and environmental problems. Earth-abundant, environmental-friendly semiconductors for supercapacitor and water splitting applications have received great attention due to their specific characteristics. It is well established that the capacitive properties of semiconductors are greatly affected by their nanostructure and poor conductivity, leading to a limited energy and power densities. Thus, understanding and manipulating the hierarchical structure at the nanoscale is essential to design composite materials for energy storage with enhanced charge transfer and electrolyte ions transportation abilities. On one hand, in photoelectrochemical water splitting (PEC), the electron-hole recombination in the bulk interfaces plays a determinative role in the catalytic performance. The investigation about modulation of the charge transfer kinetics as well as the energy level and density of surface state upon the modification of a second semiconductor or oxygen evolution catalysts (OEC) could be of great interest. On the other hand, for hydrogen evolution catalysts (HEC), as the identification of structural defects, phase transmission and vacancies presented in the 2D materials play a vital role in optimizing the catalyst for hydrogen evolution reaction (HER) in water splitting. This dissertation is divided into 7 chapters: Chapter 1 is the introduction part, which includes the background of supercapacitors and water splitting and reviews the limited factors affecting the electrochemical properties of semiconductors for supercapacitor and water splitting applications. In Chapter 2 summarizes the applied methodologies in this dissertation. This chapter includes the details about the TEM, STEM, EELS experimental setups, data processing, simulations and general introductions to the electrochemical techniques, such as cyclic voltammetry, electrochemical impedance spectrum as well the electrical circuit model for illustrating the surface states. Specific synthesis procedures and experimental results for every one of the studied nanosystems are presented in Chapters 3-6. Chapter 3 deals with the fabrication of core-branch Fe2O3/PPy nanocomposites as negative electrode for supercapacitor applications as well as the investigation of PPy nanoleaves growth mechanism onto the hematite nanoflakes. In Chapter 4, we have optimized the synthesis conditions, including the ITO thickness, TiO2 thickness, FeNiOOH deposition charge and the post-sintering temperature of ITO/Fe2O3/Fe2TiO5/FeNiOOH nanowire-based photoanodes for water splitting in alkaline electrolyte. The detailed structure has been mainly investigated by TEM and STEM-EELS, while, the charge transfer and reaction kinetic mechanisms were systematically investigated by PEIS. In Chapter 5, we have optimized the chemical bath conditions for synthesising CoFe PBA supported onto Fe2O3/Fe2TiO5 nanowire-based photoanodes for water splitting in acidic electrolyte. The detailed structure has been mainly investigated by TEM and STEM-EELS, while, the charge transfer and reaction kinetic mechanisms were investigated by PEIS. In Chapter 6, we moved the characterization of structural defects, phase transmission, vacancies in 2D materials for HER in water splitting with advanced aberration-corrected dedicated STEM, including HAADF, ABF, EELS-STEM, GPA and HAADF simulation. Finally, Chapter 7 summarizes the general conclusions of this dissertation, along with a brief outlook.
Du, Feng. "Hierarchically Structured Carbon Nanotubes for Energy Conversion and Storage." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1375459272.
Full textIn, Hyun Jin. "Origami nanofabrication of three-dimensional electrochemical energy storage devices." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32368.
Full textIncludes bibliographical references (p. 143-154).
The Nanostructured (TM) 3D Fabrication and Assembly Process was developed as a novel method of creating three-dimensional (3D) nanostructured devices using two- dimensional micro- and nanopatterning tools and techniques. The origami method of fabrication is a two-part process in which two-dimensional (2D) membranes are first patterned and then folded into the desired 3D configuration. This thesis presents an origami fabrication method based on the use of SU-8 membranes and elastic gold hinges. Magnetic actuation, stress-induced folding, vertical spacing, and lateral alignment of the membranes are discussed. This thesis also reports on the used of the Nanostructured OrigamiTM process to create a functional electrochemical energy storage device. An electrochemical capacitor, or a supercapacitor, is selected because its performance can be readily improved by the addition of 3D geometry and nanoarchitecture. In addition to improved performance, the origami fabrication method allows such devices to be integrated into preexisting MEMS and IC processes, thus enabling the fabrication of complete micro- and nanosystems with an integrated power supply. The supercapacitors were created by selectively depositing carbon-based electrode materials on the SU-8 membrane and then folding the structure so that oppositely-charged electrode regions face each other in a 3D arrangement. The fabrication process, electrochemical testing procedure, and analysis of the results are presented.
by Hyun Jin In.
S.M.
Yuan, Qifan. "Physical, electrical and electrochemical characterizations of transition metal compounds for electrochemical energy storage." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/71869.
Full textPh. D.
Venkataraman, Anuradha. "Pseudocapacitors for Energy Storage." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2486.
Full textAmani, Hamedani Hoda. "Development of novel heteronanostructures engineered for electrochemical energy conversion devices." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52158.
Full textFan, Xueliu. "Tailored 3D Graphene-Based Materials for Energy Conversion and Storage." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1503544689010898.
Full textYuan, Kai [Verfasser]. "Carbon-Based Materials for Energy Conversion and Storage / Kai Yuan." Wuppertal : Universitätsbibliothek Wuppertal, 2017. http://d-nb.info/1128841614/34.
Full textMiner, Elise Marie. "Energy storage and conversion applications of conductive metal-organic frameworks." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121783.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 182-200).
Establishing catalytic structure-function relationships enables optimization of the catalyst structure for enhanced activity, selectivity, and durability against reaction conditions and prolonged catalysis. One class of catalysts that could benefit from systematic optimization is non-platinum group metal (non-PGM) electrocatalysts for the O₂ reduction reaction (ORR) to water (4e⁻ reduction) and / or hydrogen peroxide (2e⁻ reduction). The electrically conductive metal-organic frameworks (MOFs) M₃(HXTP)₂ (HXTP = 2,3,6,7,10,11-hexaimino or hexahydroxytriphenylene (HITP or HHTP, respectively)) feature a crystalline structure that contains homogeneously distributed, square planar transition metal sites reminiscent of those doped into carbonaceous media for ORR catalysis. Ni₃(HITP)2 functions as an active and stable ORR electrocatalyst in alkaline medium.
Experimental and computational techniques enabled elucidation of the kinetics, mechanism, and active site for ORR with Ni₃(HITP)₂, as well as understanding the essential nature of the extended MOF structure in providing catalytic activity. Varying the metal and ligand combinations within this class of MOFs afforded two distinct phases. Probing the stability, catalytic activity, product distribution, and electronic properties of the two phases of MOFs identified phase-dependent catalytic activity, regardless of the metal or chelating atom identity. Since the birth of the first rechargeable battery in 1860, emerging battery technologies have both provided answers to energy demands as well as additional obstacles to navigate.
Recent works have explored using MOFs as ionically conductive solid-state electrolytes which would eliminate the need for volatile organic liquids and potentially offer a wider electrolyte potential window and means of controlling the plating of alkali metals during charging. This work has taken advantage of the modular charge found in a Cu-azolate MOF, wherein guest Cl⁻ ions coordinated to Cu₄-lined clusters can be washed out of the structure, and stoichiometric loadings of anions varying in size can be reconstituted into the MOF when soaking the MOF in solutions containing alkali or alkaline earth metal salts. The anions are held in place through coordination to the Cu²⁺ centers, thus enabling the charge-balancing metal cations to achieve high transference numbers within this solid electrolyte. Further, the versatility regarding the identity of the guest metal salt provides a handle for modulating the cation transport activation energy and ionic conductivity.
by Elise Marie Miner.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemistry
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