DOCSLIB.ORG

Electrode Materials for Supercapacitors: a Review of Recent Advances

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electrode Materials for Supercapacitors: a Review of Recent Advances catalysts Review Electrode Materials for Supercapacitors: A Review of Recent Advances Parnia Forouzandeh *, Vignesh Kumaravel and Suresh C. Pillai * Nanotechnology and Bio-Engineering Research Group, Department of Environmental Science, Institute of Technology Sligo, Ash Lane, F91 YW50 Co. Sligo, Ireland; [email protected] * Correspondence: [email protected] (P.F.); [email protected] (S.C.P.) Received: 10 July 2020; Accepted: 19 August 2020; Published: 26 August 2020 Abstract: The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-active small molecules and bio-derived functional groups displayed a significant effect on the electrochemical properties of electrode materials. These advanced properties provide a vast range of potential for the electrode materials to be utilized in different applications such as in wearable/portable/electronic devices such as all-solid-state supercapacitors, transparent/flexible supercapacitors, and asymmetric hybrid supercapacitors. Keywords: electrochemistry; 2D materials; energy storage; carbonaceous material; polymers; nanomaterials 1. Introduction Recently, due to the need for preserving natural resources and regulating global energy consumption, there has been a crucial demand for the development of clean energy sources. Among various unconventional electric-power devices, such as supercapacitors (SCs), batteries, and fuel cells, (SCs), which have been used in various fields, (e.g., hybrid cars and electric mass transit vehicles [1], and wearable/portable electronic devices [2], etc.,), SCs have inspired a vast range of research attention owing to their excellent electrochemical performances, including high specific power, superior cycling life and a rapid charging–discharging rate [3]. SCs are a type of capacitor that are also known as ultracapacitors, electrochemical capacitors (ECs) [4], gold capacitors, electrical double-layer capacitors (EDLCs), pseudocapacitors, or power coaches [5,6]. The main combination of SC configuration consists of an electrolyte, current collector, and electrodes with large specific surface area (SSA), which enhances the capacitance 10,000 times more than conventional capacitors [7,8] and thin dielectric separators, which provide higher capacitance for SC compared to conventional batteries [9]. The energy storage in SCs is based on the charge–discharge mechanism at the electrode–electrolyte interface [10] in which the principle is similar to conventional capacitors; however, the charge–discharge process is much faster in SCs [11]. The charge storage range for conventional capacitors is between Catalysts 2020, 10, 969; doi:10.3390/catal10090969 www.mdpi.com/journal/catalysts Catalysts 2020,, 10,, 969x FOR PEER REVIEW 2 of 74 72 charge–discharge process is much faster in SCs [11]. The charge storage range for conventional micro to millifarads while for SCs is between 100–1000 F for each device retaining low equivalent series capacitors is between micro to millifarads while for SCs is between 100–1000 F for each device resistance (ESR) and specific power [12]. SCs could cover both the specific energy and power density retaining low equivalent series resistance (ESR) and specific power [12]. SCs could cover both the (Pd) by several orders of magnitude compared to batteries exploiting proper design and efficient specific energy and power density (Pd) by several orders of magnitude compared to batteries materials, which make them as a flexible energy storage option [12]. The specific energy (energy exploiting proper design and efficient materials, which make them as a flexible energy storage option density) determines how long the energy storage device can be utilized, and the specific power (power [12]. The specific energy (energy density) determines how long the energy storage device can be density) signifies how rapidly a device can deliver the energy. utilized, and the specific power (power density) signifies how rapidly a device can deliver the energy. The segregating feature of the SC to the conventional capacitor is the absence of dielectric material The segregating feature of the SC to the conventional capacitor is the absence of dielectric in the SCs [13]. In comparison to SCs, conventional capacitors store and deliver very high energy material in the SCs [13]. In comparison to SCs, conventional capacitors store and deliver very high density (Ed), but the charge and discharge time of batteries is much slower. SCs also show more safety, energy density (Ed), but the charge and discharge time of batteries is much slower. SCs also show a low level of heating, device stability, light-weight, and flexible packaging [14–16]. Figure1,[ 17], more safety, a low level of heating, device stability, light-weight, and flexible packaging [14–16]. displays the Ragone plot of comparison between conventional capacitor, fuel cells, batteries, and Figure 1, [17], displays the Ragone plot of comparison between conventional capacitor, fuel cells, hybrid supercapacitors (HSCs), as various energy storage devices, in terms of power density (P ) and batteries, and hybrid supercapacitors (HSCs), as various energy storage devices, in terms of powerd Ed in which the HSCs show a significant feature of Pd in comparison with batteries and fuel cells but density (Pd) and Ed in which the HSCs show a significant feature of Pd in comparison with batteries considerably lower Pd than conventional capacitors. and fuel cells but considerably lower Pd than conventional capacitors. Figure 1. 1. RagoneRagone plot plot of the of power-energy the power-energy density density range rangefor different for di ffelectrochemicalerent electrochemical energy storage energy devices.storage devices. According to the charge storage principle, SCs can be categorized into three groups, including (a) EDLCs that exploit double layer electrodes to st storeore the charge in through non-faradic interactions (electrostatically) [18], [18], (b) pseudocapacitors in which the charge storage mechanism is faradaically through oxidation-reductionoxidation-reduction reactions reactions associated associat withed theirwith varioustheir various potential potential [19], and (c)[19], asymmetric and (c) asymmetricsupercapacitors supercapacitors (ASSC), in which, (ASSC), the in charge which, storage the charge mechanism storage mechanism of the two electrodes of the two is electrodes not similar, is notand similar, the storage and principlethe storage is basedprinciple on bothis based Faradaic on both and Faradaic non-Faradic and behaviournon-Faradic of behaviour used material of used [13]. materialGenerally, [13]. the “asymmetric”Generally, the word “asymmetric” refers to various word chargerefers storageto various mechanisms charge storage corresponding mechanisms to the positivecorresponding and negative to the positive electrodes and in thenegative SC device. electrod Accordinges in the to SC this, device. the HSC According has been to categorizedthis, the HSC as hasone ofbeen the categorized specific class as of one the of ASSC. the specific The energy class storage of the mechanismASSC. The ofenergy a device storage with mechanism supercapacitive of a devicematerials with as supercapacitive the cathode and materials a battery as material the cathode as the and anode a battery is called material HSC. ASSCsas the anode provide is acalled high HSC.energy ASSCs density provide and power a high density energy duedensity to the and extended power density operating due voltage to the extended window (upoperating to about voltage 2.0 V windowin the case (up of to aqueousabout 2.0 electrolytes,V in the case andof aqueous about 2.7electrolytes, V in organic and about electrolytes, 2.7 V in and organic even electrolytes, more than and4.0 V even in ionic more liquids) than 4.0 by V taking in ionic the liquids) advantages by ta ofking the twothe advantages different electrode of the two materials, different which electrode could materials, which could operate at different potential windows. Figure 2 represents the schematic illustration of the EDLCs, pseudocapacitors, and the HSC. Catalysts 2020, 10, 969 3 of 72 operate at different potential windows. Figure2 represents the schematic illustration of the EDLCs, pseudocapacitors, and the HSC. The main characteristics for these energy storage systems, which provide the ability to distinguish one system from others are including energy density, power density, capacitance/capacity, cell voltage, kinetic storage mechanism, i–v relationship, operating temperature, cycle life, self-discharge, and used materials as an electrode, electrolyte, etc. Compared to
Load more

Recommended publications
  • The Role and Utilization of Pseudocapacitance for Energy Storage by Supercapacitors
    University of Calgary PRISM: University of Calgary's Digital Repository Science Science Research & Publications 1997 The role and utilization of pseudocapacitance for energy storage by supercapacitors Birss, Viola I.; Conway, B. E.; Wojtowicz, J. Elsevier Conway. B. E., Birss, V. I. and Wojtowicz, J. (1997). "The role and utilization of pseudocapacitance for energy storage by supercapacitors." Journal of Power Sources, Vol. 66, Nos. 1-2: 1-14. http://hdl.handle.net/1880/44956 journal article Downloaded from PRISM: https://prism.ucalgary.ca POWER ELSEVIER Journal of Power Sources 66 (1997) 1-14 The role and utilization of pseudocapacitance for energy storage by supercapacitors B.E. Conway, V. Birss l, J. Wojtowicz 2 Chemistry Department, University of Ottawa, Ottawa, Ont., KIN 6N5, Canada Abstract The principle of utilizing the non-Faradaic double-layer capacitance of electrode interfaces as a means of storinc electrical energy was suggested and utilized in technologies initiated some 37 years ago. However, only over the last ten years has major interest been manifested in commercial development of this possibility in so-called 'supercapacitors' or 'ultracapacitors' based on the large double-layer capacitance achievable at high-area, carbon powder electrodes. In parallel with the utilization of double-layer capacitance is the possibility of use of the large pseudocapacitance that is associated with e.g. electrosorption of H or metal adatoms (underpotential deposition) and especially some redox processes. Such pseudocapacitance arises when,
    [Show full text]
  • Recent Studies on Supercapacitors with Next-Generation Structures
    micromachines Review Recent Studies on Supercapacitors with Next-Generation Structures Juho Sung and Changhwan Shin * Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-31-290-7694 Received: 27 November 2020; Accepted: 16 December 2020; Published: 18 December 2020 Abstract: Supercapacitors have shown great potential as a possible solution to the increasing global demand for next-generation energy storage systems. Charge repositioning is based on physical or chemical mechanisms. There are three types of supercapacitors—the electrochemical double layer, the pseudocapacitor, and a hybrid of both. Each type is further subdivided according to the material used. Herein, a detailed overview of the working mechanism as well as a new method for capacitance enhancement are presented. Keywords: supercapacitor; electrical double layer capacitor; EDLC; negative capacitance; energy storage system; pseudocapacitor; micropores; nanopores; ultracapacitor; Helmholtz model 1. Introduction The Fourth Industrial Revolution, which facilitates the emergence of a hyper-connected society, is the basis for data processing between people and things as well as things and things. The essence anchored in a host of electronic devices highlights the energy consumption problem to address the ever-increasing energy demand. However, the challenge confronted (based on expenditure) is proving hard to overcome. Self-powered devices are mostly based on lithium-ion batteries, which were proposed three decades ago. They demonstrate superior properties as compared to energy storage systems (ESSs) based on other materials with the highest energy storage capacity; however, the world no longer refers to them as “perfect batteries”. Moreover, the progress of battery technology would be considered as a stumbling block to the development of electrically powered industry in some parts of the world.
    [Show full text]
  • JES2016-Transport Pseudocaps Galvanostatic.Pdf
    Journal of The Electrochemical Society, 163 (2) A229-A243 (2016) A229 Electrochemical Transport Phenomena in Hybrid Pseudocapacitors under Galvanostatic Cycling Anna L. d’Entremont, Henri-Louis Girard, Hainan Wang, and Laurent Pilon∗,z Henry Samueli School of Engineering and Applied Science, Mechanical and Aerospace Engineering Department, University of California, Los Angeles, Los Angeles, California 90095, USA This study aims to provide insights into the electrochemical transport and interfacial phenomena in hybrid pseudocapacitors under galvanostatic cycling. Pseudocapacitors are promising electrical energy storage devices for applications requiring large power density. They also involve complex, coupled, and multiscale physical phenomena that are difficult to probe experimentally. The present study performed detailed numerical simulations for a hybrid pseudocapacitor with planar electrodes and binary, asymmetric electrolyte under various cycling conditions, based on a first-principles continuum model accounting simultaneously for charge storage by electric double layer (EDL) formation and by faradaic reactions with intercalation. Two asymptotic regimes were identified corresponding to (i) dominant faradaic charge storage at low current and low frequency or (ii) dominant EDL charge storage at high current and high frequency. Analytical expressions for the intercalated ion concentration and surface overpotential were derived for both asymptotic regimes. Features of typical experimentally measured cell potential were physically interpreted. These insights could guide the optimization of hybrid pseudocapacitors. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited.
    [Show full text]
  • Pseudocapacitive Oxide Materials for High-Rate Electrochemical Energy Storage
    Open Archive Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 13900 To link to this article : DOI:10.1039/c3ee44164d URL : http://dx.doi.org/10.1039/c3ee44164d To cite this version: Augustyn, Veronica and Simon, Patrice and Dunn, Bruce Pseudocapacitive oxide materials for high-rate electrochemical energy storage. (2014) Energy & Environmental Science, vol. 7 (n° 5). pp. 1597-1614. ISSN 1754-5692 Any correspondence concerning this service should be sent to the repository administrator: [email protected] Pseudocapacitive oxide materials for high-rate electrochemical energy storage Veronica Augustyn,†a Patrice Simonbc and Bruce Dunn*a Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in DOI: 10.1039/c3ee44164d aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end. Broader context The importance of electrical energy storage will continue to grow as markets for consumer electronics and electrication of transportation expand and energy storage systems for renewable energy sources begin to emerge.
    [Show full text]
  • Preparation and Characterization of a Pseudocapacitor Electrode By
    Available online at www.sciencedirect.com View metadata, citation and similar papers at core.ac.uk brought to you by CORE ScienceDirect provided by Elsevier - Publisher Connector Journal of Taibah University for Science 10 (2016) 281–285 Preparation and characterization of a pseudocapacitor electrode by spraying a conducting polymer onto a flexible substrate a b,∗ a b Shaker A. Ebrahim , Mohamed E. Harb , Moataz M. Soliman , Mazhar B. Tayel a Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, P.O. Box 832, Egypt b Department of Electrical Engineering, Faculty of Engineering, Alexandria University, P.O. Box 21544, Egypt Received 31 March 2015; received in revised form 9 June 2015; accepted 9 July 2015 Available online 31 August 2015 Abstract In this paper, polyaniline is deposited using a spraying technique onto a flexible current collector for pseudocapacitor applications. The polyaniline is characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical absorption studies. The energy density of a pseudocapacitor is higher than that of double-layer supercapacitors due to Faradaic reactions. A high specific capacitance of 594.92 F/g is obtained at a scan rate of 5 mV/s with a scanning potential window of (−0.8 to 0.8 V). The results show an increase in the energy density of 82.63 W h/kg at a potential difference of 1 V using a 4 M potassium hydroxide aqueous electrolyte. © 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of Taibah University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
    [Show full text]
  • Energy Storage: EDLC & Pseudo – Capacitors
    Energy storage: EDLC & Pseudo – Capacitors Doron Aurbach Department of chemistry, Bar Ilan University Ramat-Gan 52900 Israel Email: [email protected] Energy is found everywhere we just need to harvest and store it We lack good storage technologies Supercapacitors can be used for load leveling applications We want to move ASAP to sustainable energy overview Material design Aqueous SC High voltage SC PsC Summery SuprecapacitorsBatteries are evaluated (EDLC) in fill terms the Energy of energy Vs. Power gap betweenand power batteries densities and capacitors 105 capacitor 1 s 1 min ECs (2008) ) ) 1 1 - - 104 Wkg Wkg Comm. Li-ion 5V. Li-ion 1h 103 Ni/MH Ni/Cd Primary Li 102 Specific Power ( Specific Power Specific Power ( Specific Power 10 Lead acid 1 10-2 10-1 1 10 102 103 Specific energy (Whkg-1) A typical Ragone plot, of common Faradaic electrochemical energy storage cells (time constants in red) overview Material design Aqueous SC High voltage SC PsC Summery What is Capacitor? • A capacitor (originally known as condenser) is a passive two- terminal electrical component used to store energy in an electric field. • When there is a potential difference across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge to accumulate on the other plate. Energy is formed in terms of electrostatic field. overview Material design Aqueous SC High voltage SC PsC Summery What is Supercapacitor? Supercapacitor (SC) also known as electric double-layer capacitor (EDLC) or Ultracapacitor, is electrochemical capacitor. The capacitance value of an electrochemical capacitor is determined by two storage principles, which both contribute indivisibly to the total capacitance: • Double layer capacitor – Electrostatic storage achieved by separation of charge in a Helmholtz double layer at the interface between the surface of a conductive electrode and an electrolyte.
    [Show full text]
  • Electrodeposition of Nickel Cobalt Oxide for the Application of Asymmetric Flexible Microsupercapacitor
    Electrodeposition of Nickel Cobalt Oxide for the Application of Asymmetric Flexible Microsupercapacitor A Thesis Submitted towards Partial Fulfilment of BS-MS Dual Degree Program By Kaustubh Tarmale Reg. No. 20121068 Under the guidance of Prof. Satishchandra B. Ogale Department of Physics and Chair for Centre of Energy Science IISER Pune, India To Department of Chemistry Indian Institute of Science Education and Research (IISER) Pune 1 Acknowledgement I like to express my heartfelt gratitude and special appreciation to my supervisor, Prof. Satishchandra B. Ogale, for providing me the opportunity to work on my Master’s thesis. His highly enthusiastic and positive nature, patience, scientific advice, cooperation, immense knowledge is the key for successful completion of my thesis work in available time frame. By giving excellent environment, freedom which every researcher earnestly desires has not only helped me during the time of master thesis but also developed my thinking ability to become an independent thinker. I like to express my deep gratitude to my TAC member Dr. M. Musthafa who has supported me during the course of my master thesis by periodic discussions and motivation which has helped me a lot to complete the task. I would also like to express my deep gratitude and special thanks to Dr. Aniruddha Basu, Yogesh Gawali for their kind support and guidance during the course of my work. I also like to convey my thanks to all my lab mates Dr. Pradeep, Dr. Dhanya, Dr. Abhik, Dr. Rounak, Dr. Anil, Dr. Satish, Dr. Monika, Umesh, Rahul,Vishal, Roma, Kingshuk, Rajesh, Mukta, Dr. Supriya, Dr. Neelima, Poonam, Swati, Srashti, Harshita, Divya, Dr.
    [Show full text]
  • Capacitors Store Electrical Charge
    FUNDAMENTALS OF ELECTROCHEMICAL CAPACITOR DESIGN AND OPERATION by John R. Miller and Patrice Simon apacitors store electrical charge. CBecause the charge is stored physically, with no chemical or phase changes taking place, the process is highly reversible and the discharge-charge cycle can be repeated over and over again, virtually without limit. Electrochemical capacitors (ECs), variously referred to by manufacturers in promotional literature as “supercapacitors” or “ultracapacitors,” store electrical charge in an electric double layer at the interface between a high-surface-area carbon electrode and a liquid electrolyte.1,2 Consequently, they are also quite properly referred to as electric double layer capacitors. A simple EC can be constructed by inserting two conductors in a beaker containing an electrolyte, for example, two carbon rods in salt water (Fig. 1). Initially there is no measurable voltage between the two rods, but when the switch is closed FIG. 2. Idealistic representation of an electrolyte-filled right-cylindrical nanopore in a carbon electrode of an electrochemical capacitor showing the distributed resistance from the electrolyte and distributed charge storage down the interior surface of the nanopore. pore, electrolyte conductivity being much less than carbon conductivity. Charge stored near the pore mouth is accessible through a short path with small electrolyte resistance. In contrast, charge stored deeper within the pore must traverse a longer electrolyte path with a significantly higher series resistance. Thus, the overall response can be represented by a multiple-time-constant equivalent circuit model.4-6 Irrespective of this behavior, the response time of an electrochemical capacitor in both charge and discharge operation is extremely short, about 1 second, as compared to batteries (minutes to tens of minutes).
    [Show full text]
  • Exploring the Synergy of Functionalized Bio-Carbons And
    Exploring the Synergy of Functionalised Bio-carbons and their Performance in Supercapacitor Devices Dina Ibrahim Abouelamaiem Submitted in part fulfilment of the requirements for the degree of Doctor of Philosophy at University College London Electrochemical Innovation Lab Department of Chemical Engineering University College London 2018 To my beloved mom Sophie, grandparents, Dan (d) and Oscar 1 Declaration I, Dina Ibrahim Abouelamaiem, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. …………………………… Signature …………………………… Date 2 Acknowledgements I am not sure where to start as I can go forever in the only personal section (but also so close to my heart) in this thesis. It all started on the 19th of October, 2014 when I knew that Dan Brett will be my PhD supervisor, and I will never forget how I danced on my bed back in Lebanon that night. I was so scared the first time I met you, and wasn’t sure if I will fit in the EIL, but I have changed so much over the course of 4 years, hugely because of you. Dan, I can’t start to describe how much I love you and appreciate all your support for me throughout the years. I will always see a dad character in you that I never had, though you are not that old. The support, respect and appreciation you have shown me throughout the years, I will never forget. You have seen and treated me as a person, and not a number in your group, and that is quite rare these days.
    [Show full text]
  • Understanding the Pseudocapacitance of Ruo2 from Joint Density Functional Theory
    Understanding the pseudocapacitance of RuO2 from joint density functional theory Cheng Zhan and De-en Jiang* Department of Chemistry, University of California, Riverside, 92521, CA, USA *E-mail: [email protected]. Tel.: +1-951-827-4430 Abstract: Pseudocapacitors have been experimentally studied for many years in electric energy storage. However, first principles understanding of the pseudocapacitive behavior is still not satisfactory due to the complexity involved in modeling electrochemistry. In this paper, we applied a novel simulation technique called Joint Density Functional Theory (JDFT) to simulate the pseudocapacitive behavior of RuO2, a prototypical material, in a model electrolyte. We obtained from JDFT a capacitive curve which showed a redox peak position comparable to that in the experimental cyclic voltammetry (CV) curve. We found that the experimental turning point from double-layer to pseudocapacitive charge storage at low scan rates could be explained by the hydrogen adsorption at low coverage. As the electrode voltage becomes more negative, H coverage increases and causes the surface structure change, leading to bended –OH bonds at the on-top oxygen atoms and large capacitance. This H coverage-dependent capacitance can explain the high pseudocapacitance of hydrous RuO2. Our work here provides a first principles understanding of the pseudocapacitance for RuO2 in particular and for transition-metal oxides in general. 1. Introduction Capacitors are an important electronic device that can store and release electrical energy
    [Show full text]
  • Electrodeposited Transition Metal Oxide and Selenide Thin
    Electrodeposited Transition Metal Oxide and Selenide Thin Films for Supercapacitor Zhenjun Qi A thesis in fulfilment of the requirements for the degree of Doctor of Philosophy School of Materials Science & Engineering Faculty of Science University of New South Wales September 2020 PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: QI First name: ZHENJUN Other name/s: Abbreviation for degree as given in the University calendar: Doctor of philosophy School: School of Materials Science and Engineering Faculty: Faculty of Science Title: Electrodeposited Transition Metal Oxide and Selenide Thin Films for Supercapacitor Abstract 350 words maximum: (PLEASE TYPE) As electrode materials of supercapacitors, transition metal oxide and selenide can exhibit superior specific capacitance and energy density, owing to their rich valence states for reversible faradaic reactions. In this dissertation, the simple and fast electrochemical deposition method has been implied to directly deposit transition metal oxide and selenide on suitable substrates to form thin films, which effectively avoids the use of polymer binders and conductive additives, thereby reducing the loss of electrode capacity. Moreover, the morphology, structure and composition of thin films can be controlled for better performance by simply adjusting the electrodeposition parameters, such as temperature, current, potential, and the composition of electrolyte. The main aspects of this research are as follows: (i) A temperature-controlled electrodeposition method was designed and utilized to Mn3O4 and Mn3O4/MnOOH nanocomposite thin films on FTO substrates. The performance of Mn3O4 based electrode was improved due to the optimized morphology and the synergistic effect between Mn3O4 and MnOOH. (ii) Mn3O4/MnOOH thin film with nanorods morphology was obtained by introducing Pt atoms during the electrodeposition and exhibited a superior electrochemical behaviour.
    [Show full text]
  • 1 Dr. Ralph E. White September 1, 2018 Professor, Chemical
    Dr. Ralph E. White September 1, 2018 Professor, Chemical Engineering Birth date: November 6, 1942 Citizenship: U.S. Birthplace: Clovis, New Mexico Security Clearance: None Number of Children: 5 Address: Department of Chemical Engineering Swearingen Engineering Center, Room 3C11 University of South Carolina Columbia, South Carolina 29208 Phone: 803 777 3270 Cell: 803 240 7132 E-mail [email protected] Research Interests: Electrochemical Systems, Mathematical Modeling, Batteries, Corrosion, & Electrodeposition EDUCATION B.S., Engineering, University of South Carolina, 1971 M.S., Chemical Engineering, University of California at Berkeley, 1973 (Advisor – Robert P. Merrill) Ph.D., Chemical Engineering, University of California at Berkeley, 1977 (Advisor – John S. Newman) 1 EXPERIENCE Educational Assistant Professor, Chemical Engineering, Texas A&M University, 1977–1981 Associate Professor, Chemical Engineering, Texas A&M University, 1981–1985 Professor, Chemical Engineering, Texas A&M University, 1985–1993 Associate Head of the Department of Chemical Engineering, Texas A&M University, 1990–1993 Professor, Chemical Engineering, University of South Carolina, 1993–present Chairman of the Department of Chemical Engineering, University of South Carolina, 1993–2000 Distinguished Scientist, University of South Carolina, 1993-present Director, Center for Electrochemical Engineering, University of South Carolina, 1995- 2000 Dean, College of Engineering and Computing, Univ. of South Carolina 2000- 2005 Industrial Chemical Engineer, Ethyl Corporation,
    [Show full text]