DOCSLIB.ORG

Evaluation of Electrolytes for Redox Flow Battery Applications

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evaluation of Electrolytes for Redox Flow Battery Applications Electrochimica Acta 52 (2007) 2189–2195 Evaluation of electrolytes for redox flow battery applications M.H. Chakrabarti a, R.A.W. Dryfe b, E.P.L. Roberts a,∗ a School of Chemical Engineering and Analytical Science, The University of Manchester, P.O. Box 88, Manchester M60 1QD, UK b School of Chemistry, The University of Manchester, P.O. Box 88, Manchester M60 1QD, UK Received 17 May 2006; received in revised form 1 August 2006; accepted 17 August 2006 Available online 26 September 2006 Abstract A number of redox systems have been investigated in this work with the aim of identifying electrolytes suitable for testing redox flow battery cell designs. The criteria for the selection of suitable systems were fast electrochemical kinetics and minimal cross-contamination of active electrolytes. Possible electrolyte systems were initially selected based on cyclic voltammetry data. Selected systems were then compared by charge/discharge experiments using a simple H-type cell. The all-vanadium electrolyte system has been developed as a commercial system and was used as the starting point in this study. The performance of the all-vanadium system was significantly better than an all-chromium system which has recently been reported. Some metal–organic and organic redox systems have been reported as possible systems for redox flow batteries, with cyclic voltammetry data suggesting that they could offer near reversible kinetics. However, Ru(acac)3 in acetonitrile could only be charged efficiently to 9.5% of theoretical charge, after which irreversible side reactions occurred and [Fe(bpy)3](ClO4)2 in acetonitrile was found to exhibit poor charge/discharge performance. © 2006 Elsevier Ltd. All rights reserved. Keywords: Redox flow battery; Vanadium; Chromium; Ru(acac)3; [Fe(bpy)3](ClO4)2 1. Introduction electrolytes by transport through the membrane. For example, there has been little recent interest in the development of the Redox flow batteries are electrochemical energy storage iron/chromium redox flow cell due to this problem [4]. Toredress devices that utilise the oxidation and reduction of two soluble this issue, an all-chromium redox electrolyte was investigated at redox couples for charging and discharging. They differ from the University of Manchester and the charge/discharge charac- conventional batteries in that the energy-bearing chemicals are teristics of a laboratory scale battery were reported [5,6]. Prior not stored within at the electrode surface, but in separate liquid to this, other workers have performed extensive investigations reservoirs and pumped to the power converting device for either on the all-vanadium redox system [3,7–10] and patented the charging or discharging [1,2]. Due to the use of two soluble redox technology [11]. In addition, an all-neptunium system has been couples, solid-state reactions with their accompanying morpho- evaluated [12], although the hazards of working with radioac- logical changes at the electrodes are absent [3]. Thus, there are tive electrolytes are likely to limit the practical application of this no fundamental cycle life limitations associated with these pro- system. Several prototype vanadium systems have been investi- cesses such as shedding or shape changes, which usually occur gated successfully [13–16] and some systems are well on their in conventional storage batteries. way to commercial success [17]. Despite these advantages, the redox flow battery has not been Despite such achievements, batteries employing aqueous widely exploited to date. One disadvantage of the systems devel- electrolytes have a low energy content. The energy output from oped to date is the use of two separate redox species in the half- the battery is proportional to the potential window of opera- cells, leading to the potential for cross-contamination of active tion available from the background electrolyte. The operating potential window of aqueous electrolytes is limited due to water electrolysis [5]. Organic electrolytes, which offer a wider poten- ∗ Corresponding author. Tel.: +44 161 306 8849; fax: +44 161 306 4399. tial window, have been investigated in this study. In addition, E-mail address: [email protected] (E.P.L. Roberts). species have been selected which minimize the effect of elec- 0013-4686/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.electacta.2006.08.052 2190 M.H. Chakrabarti et al. / Electrochimica Acta 52 (2007) 2189–2195 trolyte cross-contamination. One approach is to use a single give an indication of the reversibility of redox couples, further system which offers three oxidation states, so that the discharged experiments are needed to demonstrate that selected systems can species is the same on each side of the cell. Such a system would be used for energy storage. For example, a redox couple may be have the advantage that any cross-contamination would only lead reversible, but the charged species may be unstable over long to some self-discharge, and little or no ‘cell balancing’ or elec- timescales, which would not be detected by cyclic voltammetry. trolyte processing would be required. An approach whereby the In this study systems which were found to exhibit fast kinetics same cation is used but with different ligands on each side of the were tested for their charge/discharge performance in a simple cell has been suggested [18], but this has not been considered in H-type cell. These experiments aimed to determine whether the this study. selected systems could be used for energy storage and to pro- Electrolyte systems can be selected on the basis of the fol- vide a preliminary indication of the relative performance of each lowing properties, which are generally desirable for redox flow system. batteries [18,19]: 2. Experimental • fast kinetics at the electrode–electrolyte interface; • a relatively large open circuit potential; 2.1. Electrolytes • reasonable cost; • high solubility in the process electrolyte. Vanadium electrolytes were prepared from vanadium (IV) sulphate (>99.99% purity, Aldrich), with the V(II)/V(III) couple In this study, the following series of redox systems in ace- generated by electro-reduction. Sulphuric acid was used as the tonitrile electrolyte were selected which apparently offered fast background electrolyte. electrode kinetics (based on literature data, e.g. [19] and [20]) Reagent grade tris(2,2-bipyridine) ruthenium (II) chloride and the potential to operate with a single electrolyte using a is available from Aldrich. Since oxidation of the chloride salt species with three oxidation states. was known to be irreversible [24], the tetrafluouroborate salt [Ru(bpy)3(BF4)2] was prepared by addition of NaBF4 in ace- (i) Ruthenium organic complexes tonitrile and precipitation of NaCl. Ruthenium acetylacetonate A number of ruthenium organic complexes which can [Ru(acac)3, 97% purity, Aldrich], tris(2,2 -bipyridine) iron(II) be both oxidized and reduced electrochemically have been perchlorate (reagent grade, GFS) and rubrene (reagent grade, reported in the literature, and some of these have been Aldrich) were used for the preparation of the respective elec- suggested as suitable candidates for a redox flow battery trolytes (Caution: perchlorate salts are potentially explosive and [21]. Tris(2,2-bipyridine) ruthenium (II) tetrafluoroborate should be handled with appropriate care). Tetraethyl-ammonium [Ru(bpy)3(BF4)2] has exhibited fast kinetics [19]. In addi- tetrafluoroborate and tetraethyl-ammonium perchlorate were tion, this system offers the possibility of cell voltages of up used as the background electrolyte. to 2.6 V, much higher than is possible in aqueous battery To remove dissolved oxygen, electrolytes were sparged for at systems [19]. Ruthenium acetylacetonate [Ru(acac)3] has least 10 min with oxygen-free dry argon (aqueous electrolytes) also been reported as offering fast oxidation and reduction or nitrogen (organic electrolytes). Water was removed from the kinetics [22] and a possible cell voltage of around 1.75 V. organic electrolytes using zeolite 4A (Merck) to a moisture level (ii) Tris(2,2-bipyridine) iron(II) perchlorate of below 0.005 wt%. This species can be oxidized and reduced [19] and offers a possible cell potential of 2.4 V. This compound is avail- 2.2. Cyclic voltammetry able commercially and is significantly cheaper than the ruthenium complexes. A graphite rod (Goodfellow) of surface area 0.06 cm2 was (iii) Rubrene used as the working electrode for cyclic voltammogram exper- Rubrene, a neutral organic species, can be oxidized and iments with the vanadium battery electrolytes. A glassy-carbon reduced electrochemically [23]. The redox potentials of electrode (I.J. Cambria Scientific) of surface area 0.07 cm2 was these reactions offer a possible cell potential of around used for cyclic voltammetry in organic media. The electrode 2.3 V. Again this compound is available commercially, was polished with alumina washed with de-ionised water and although it is significantly more expensive than the other acetone following the procedure described in literature [21]. redox species. The reference electrode used in aqueous solutions was the saturated calomel electrode along with a salt bridge. Organic These systems are compared to the all vanadium redox flow media required the use of a silver wire quasi-reference elec- battery system, which has previously been investigated in detail trode (AgQRE). A platinum counter electrode was used in each ([3,7–11]) and has been commercialized in recent years [17]. case. In this system, vanadium in four different oxidation states is Cyclic voltammetry was conducted using a standard three- used: V(II)/V(III) at the negative electrode and V(IV)/V(V) at electrode cell, with a Autolab/PGSTAT30potentiostat for poten- the positive electrode. tial control. All solutions were de-aerated prior to experiments. Each system was first tested by cyclic voltammetry in order The solution headspace was purged with inert gas for the dura- to evaluate the electrode kinetics. While cyclic voltammetry can tion of experiments.
Load more

Recommended publications
  • Liquid Junction Potentials at Mixed Electrolyte Salt
    LIQUID JUNCTION POTENTIALS AT MIXED ELECTROLYTE SALT BRIDGES. A Thesis 2ubmitted in Part-Fulfilment of the Requirements for the Degree of Master of Science of Rhodes University. BY NOEL PHILLIP FINKELSTEIN. RHODES UNIVERSITY, GRAHAli-1STmVN. September, 1956. ( i) ACKNOJLEDGJ:!Ji.fuNTS. It is with sincere gratitude that the following acknowledgements are made: DR . E.T. VE~DISR , M.Sc., (S.A.); Docteur es Sciences Physiques (France), for his able dir$ction, guidance, and constant encoura~ement. PROFESSOR W.F. BA~KER, B.Sc., Ph.D., F.R.I.C. F.n.s.s. Af., for his encouragement and interest. PHOFESSOR J.A. GLEDHILL , Ph.D., (S.A.), Ph.D., (Yale), for long hours of in­ valuable discussion. Mr. F. van der VI/A Tim, for his skilful and patient assistance with the technical aspects of the work. Mr. D.A. CLUR, B.Sc., (Hons.) for much in­ valuable discusssion, and many useful suggestions. Mrs. J. FINKELSTbiN, for her assistance with the clerical side of the pre­ paration of the thesis. Mr. H.T. DREYER, who was responsible for the diagrams. THE SOUTH AFRICAN COUNCIL FOH SCI~NTI?IC AND INDUSTRIAL RESJ:;AllCH for a grant held during this research. ( ii) CONTENTS . £ (( 'i j . AC KNO':-.ILED£}]-1ENTS (1) 1. GLOSSARY OF ABBREVIATIONS AND SYMBOLS. 1. 2. INTRODUCTimT. 3 . 3. CRITICAL SURVEY ON PREVIOUS WORK ON LIQUID JUNCTION POTEN~IALS. 5· 3.1. The Theory of Liquid Junction Pot- entials . 5· 3. 2. The ~l i m ination of the Error due to Liquid Junction Potentials . g. 3~3. The Measurement of Liquid Junction Potentials .
    [Show full text]
  • Galvanic Cell Notation • Half-Cell Notation • Types of Electrodes • Cell
    Galvanic Cell Notation ¾Inactive (inert) electrodes – not involved in the electrode half-reaction (inert solid conductors; • Half-cell notation serve as a contact between the – Different phases are separated by vertical lines solution and the external el. circuit) 3+ 2+ – Species in the same phase are separated by Example: Pt electrode in Fe /Fe soln. commas Fe3+ + e- → Fe2+ (as reduction) • Types of electrodes Notation: Fe3+, Fe2+Pt(s) ¾Active electrodes – involved in the electrode ¾Electrodes involving metals and their half-reaction (most metal electrodes) slightly soluble salts Example: Zn2+/Zn metal electrode Example: Ag/AgCl electrode Zn(s) → Zn2+ + 2e- (as oxidation) AgCl(s) + e- → Ag(s) + Cl- (as reduction) Notation: Zn(s)Zn2+ Notation: Cl-AgCl(s)Ag(s) ¾Electrodes involving gases – a gas is bubbled Example: A combination of the Zn(s)Zn2+ and over an inert electrode Fe3+, Fe2+Pt(s) half-cells leads to: Example: H2 gas over Pt electrode + - H2(g) → 2H + 2e (as oxidation) + Notation: Pt(s)H2(g)H • Cell notation – The anode half-cell is written on the left of the cathode half-cell Zn(s) → Zn2+ + 2e- (anode, oxidation) + – The electrodes appear on the far left (anode) and Fe3+ + e- → Fe2+ (×2) (cathode, reduction) far right (cathode) of the notation Zn(s) + 2Fe3+ → Zn2+ + 2Fe2+ – Salt bridges are represented by double vertical lines ⇒ Zn(s)Zn2+ || Fe3+, Fe2+Pt(s) 1 + Example: A combination of the Pt(s)H2(g)H Example: Write the cell reaction and the cell and Cl-AgCl(s)Ag(s) half-cells leads to: notation for a cell consisting of a graphite cathode - 2+ Note: The immersed in an acidic solution of MnO4 and Mn 4+ reactants in the and a graphite anode immersed in a solution of Sn 2+ overall reaction are and Sn .
    [Show full text]
  • Chapter 13: Electrochemical Cells
    March 19, 2015 Chapter 13: Electrochemical Cells electrochemical cell: any device that converts chemical energy into electrical energy, or vice versa March 19, 2015 March 19, 2015 Voltaic Cell -any device that uses a redox reaction to transform chemical potential energy into electrical energy (moving electrons) -the oxidizing agent and reducing agent are separated -each is contained in a half cell There are two half cells in a voltaic cell Cathode Anode -contains the SOA -contains the SRA -reduction reaction -oxidation takes place takes place - (-) electrode -+ electrode -anions migrate -cations migrate towards the anode towards cathode March 19, 2015 Electrons move through an external circuit from the anode to cathode Electricity is produced by the cell until one of the reactants is used up Example: A simple voltaic cell March 19, 2015 When designing half cells it is important to note the following: -each half cell needs an electrolyte and a solid conductor -the electrode and electrolyte cannot react spontaneously with each other (sometimes carbon and platinum are used as inert electrodes) March 19, 2015 There are two kinds of porous boundaries 1. Salt Bridge 2. Porous Cup · an unglazed ceramic cup · tube filled with an inert · separates solutions but electrolyte such as NaNO allows ions to pass 3 through or Na2SO4 · the ends are plugged so the solutions are separated, but ions can pass through Porous boundaries allow for ions to move between two half cells so that charge can be equalized between two half cells 2+ 2– electrolyte: Cu (aq), SO4 (aq) 2+ 2– electrolyte: Zn (aq), SO4 (aq) electrode: zinc electrode: copper March 19, 2015 Example: Metal/Ion Voltaic Cell V Co(s) Zn(s) Co2+ SO 2- 4 2+ SO 2- Zn 4 Example: A voltaic cell with an inert electrode March 19, 2015 Example Label the cathode, anode, electron movement, ion movement, and write the half reactions taking place at each half cell.
    [Show full text]
  • Electrochemical Cells - Redox Reactions Can Be Used in a Controlled Manner to Make a Battery
    Chapter 17 Worksheet #2 Name __________________________ Electrochemical Cells - Redox reactions can be used in a controlled manner to make a battery. A galvanic cell (voltaic cell or battery) converts the chemical energy of the reactants into electrical energy. BATTERY: Anode - AN OX, RED CAT Cathode - Salt Bridge - A tube containing a salt (such as KCl or NaNO3) solution that is used to connect two half-cells in an electrochemical cell; allows the passage of ions (maintains charge neutrality), but prevents the mixing of half-cell electrolytes. Shorthand notation for a galvanic cell: Zn(s)│Zn2+(aq)║Cu2+(aq)│Cu(s) where the anode is on the left, the cathode on the right, │ indicates the interface between the metal and solution, and ║ indicates the salt bridge. In many cells, the electrode itself does not react but serves only as a channel to direct electrons to or from the solution where a reaction involving other species takes place. The electrode itself is unaffected. Platinum and graphite are inert in most (but not all) electrochemical reactions. The Cu electrode could be replaced by a platinum or graphite electrode in the Zn/Cu battery: Zn(s)│Zn2+(aq)║Cu2+(aq)│Pt(s) Construct a battery from the reaction: Cr(s) + Pb2+(aq) Cr3+(aq) + Pb(s) Construct a galvanic cell using platinum electrodes and the reaction: - - + 2+ 10 Br (aq) + 2 MnO4 (aq) + 16 H (aq) 5 Br2(ℓ) + 2 Mn (aq) + 8 H2O(ℓ) A salt bridge is not required in a battery in which the reactants are physically separated from each other.
    [Show full text]
  • Stability of Positive Electrolyte Containing Trishydroxymethyl Aminomethane Additive for Vanadium Redox Flow Battery
    Int. J. Electrochem. Sci., 7 (2012) 4388 - 4396 International Journal of ELECTROCHEMICAL SCIENCE www.electrochemsci.org Stability of Positive Electrolyte Containing Trishydroxymethyl Aminomethane Additive for Vanadium Redox Flow Battery Sui Peng1, Nangfang Wang1,2, Chao Gao1, Ying Lei1, Xingxing Liang1, Suqin Liu1,* , Younian Liu1 1 Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China 2 School of Chemistry and Chemical Engineering, Hunan Institute of Engineering, xiangtan 411104, China *E-mail: [email protected] Received: 10 March 2012 / Accepted: 24 March 2012 / Published: 1 May 2012 Trishydroxymethyl aminomethane (Tris) was used as an additive of the positive electrolyte for all vanadium redox battery (VRB) and cycling and electrochemical stabilities of the positive electrolyte were investigated. The 50 cyclic voltammetry (CV) cycles suggested that the positive electrolyte with the Tri additive after charge-discharge cycles has good cycle stability compared to that before the charge-discharge cycles. The VRB employing the vanadium electrolyte with the Tris additive as positive electrolyte exhibited better charge-discharge behavior and less discharge capacity fade rate with cycles compared with the blank electrolyte system. The UV/visible spectroscopy showed that the vanadium concentration in the positive electrolyte containing Tri additive during 40 charge-discharge cycles remains unchanged. The X-ray photoelectron spectroscopy (XPS) verified that the positive electrolyte with the Tri additive has no etching and oxidation effect on the carbon felt electrode. Keywords: Vanadium redox flow battery; additive; stability; electrochemical stability 1. INTRODUCTION All vanadium redox flow battery (VRB) is a promising energy conversion device that employs V(V)/ V(II)/V(III) and V(IV)/V(V) couples in the negative and positive half-cells respectively to store chemical potential energy [1-3].
    [Show full text]
  • Potato Power
    Potato Power Author: Nick Robertson Date Created: Spring 2008 Subject: Chemistry Level: Middle School Standards: New York State-Physical Setting/Chemistry (www.emsc.nysed.gov) Standard 1- Analysis, Inquiry and Design Standard 4 - The Physical Setting Standard 6 - Interconnectedness: Common Themes Standard 7- Interdisciplinary Problem Solving Schedule: One 60 minute period Objectives: Vocabulary: Understand what an electrochemical Voltaic cell Cathode cell is and how it can be used to Oxidation Anode power a small device. Reduction Materials: For Each Group: For Class: Covered wire with Voltmeter (optional) Students will: alligator clips at both ends. Build a voltaic cell using a potato Potatoes, apples, oranges, etc, for to power a small device. students to try Compare the effectiveness of Zinc strips or various types of fruits and galvanized nails vegetables in powering a small Copper strips or device. copper pennies Device to be powered Safety: This activity does not contain any safety concerns. Science Content for the Teacher: This lesson is based off of the concepts surrounding an electrochemical cell. There is an anode and a cathode that is separated by an electrolyte, and are connected by an electrically conducing wire. At the cathode, reduction occurs and at the anode, oxidation occurs. To determine the flow of electrons, the mnemonic device “LEO the lion goes GER” can be used. LEO means “loses electrons oxidized” and GER means “gains electrons reduction.” Therefore electrons are flowing from the anode to the cathode. Most general chemistry text books have very nice figures to demonstrate these concepts. For more information and pictures, visit http://mooni.fccj.org/~ethall/2046/ch18/galvanic.htm A common galvanic cell uses zinc and copper as the electrodes, which are the metals the students will use this project.
    [Show full text]
  • Energy Storage Outline Air Pollution
    Energy storage February 12, 2009 Outline Energy Storage • Review last week • Why do we store energy? Larry Caretto • What kind of energy is stored? Mechanical Engineering 496ALT • Fuels as energy storage Alternative Energy • Batteries • Thermal energy storage February 12, 2009 • Electrical energy storage • Mechanical energy storage 2 Air Pollution • Clean Air Act requirements – National ambient air quality standatds for criteria pollutanta • States must submit plans (state implementation plans or SIPs) to achieve standards by date – Toxic pollutants by separate process – Acid rain program by 1990 CAA amendment – Mobile vs stationary sources – Permitting requirements – Fossil fuel combustion biggest source 3 4 5 6 ME 496ALT – Alternative Energy 1 Energy storage February 12, 2009 Ozone Production Cap-and-Trade Programs • Emission requirements set for all sources in an area • Sources have three options – Comply with emission limits – Produce excess emissions and buy credits from others who generate credits – Reduce emissions beyond requirements to generate credits for sale • Alternative to “command and control” 7 8 Acid Deposition Results Ozone Layer and Greenhouse • Stratospheric ozone reduces UV radiation reaching planet’s surface • Chlorofluorocarbons (CFCs) reach stratosphere and destroy ozone • Natural balance between solar radiation reaching earth and IR radiation leaving • Balance upset by human activities producing “greenhouse gases”, espe- cially CO2 from fossil fuel combustion 9 10 IPCC 2007 reports Greenhouse Gases • Intergovernmental
    [Show full text]
  • A Lithium Iron Phosphate Reference Electrode for Ionic Liquid Electrolytes
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by espace@Curtin © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/ by-nc-nd/4.0/ A Lithium Iron Phosphate Reference Electrode for Ionic Liquid Electrolytes Johannes Wandt, Junqiao Lee, Damien W.M. Arrigan, Debbie S. Silvester* Curtin Institute for Functional Molecules and Interfaces & School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia. *E-mail: [email protected]; Fax: +61(8)92664699; Tel: +61(8)92667148 Abstract We report on the development of a very simple and robust reference electrode suitable for use in room temperature ionic liquids, that can be employed with planar devices. The reference electrode is based on LiFePO4 (LFP), a common cathode material in Li-ion batteries, which is air and water stable. The reference electrode can be drop-cast onto a planar electrode device in a single step. We demonstrate that very low Li+-ion concentrations (millimolar or below) are sufficient to obtain a stable and reproducible LFP potential, thus making physical separation between the reference and working electrode unnecessary. Most importantly, the LFP potential is also entirely stable in the presence of oxygen and only shows a very small drift (less than 10 mV) in the presence of hydrogen gas, while the potential of a platinum pseudo-reference electrode is shifted more than 800 mV. This is the first time that such a stable reference electrode system for ionic liquids has been implemented in miniaturized, planar electrode devices.
    [Show full text]
  • Electrochemistry Is the Branch of Chemistry Concerned with the Interrelation of Electrical and Chemical Changes That Are Caused by the Passage of Current.”
    11/9/2020 Madan Mohan Malaviya University of Technology, Gorakhpur-273010 “Electrochemistry is the branch of chemistry concerned with the interrelation of electrical and chemical changes that are caused by the passage of current.” “Chemical reactions that involve the input or generation of electric currents are called electrochemical reactions.” “A device capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions is called Electrochemical cell.” CESD, MMMUT, Gorakhpur-273010 1 11/9/2020 Madan Mohan Malaviya University of Technology, Gorakhpur-273010 “A Galvanic cell is an electrochemical cell that produces electricity as result of spontaneous reaction occurring in it.” “A Galvanic cell is a device in which the free energy of a physical or chemical process is converted in to electrical energy.” It is also called as Voltaic (voltage generated) cell. Daniell Cell: A Daniell cell is the best example of a galvanic cell which converts chemical energy into electrical energy. The Daniell cell consists of two electrodes of dissimilar metals, Zn and Cu; each electrode is in contact with a solution of its own ion; Zinc sulphate and copper sulphate respectively. Zn(s) + Cu2+(aq) Zn2+(aq) + Cu (s) 2 11/9/2020 Madan Mohan Malaviya University of Technology, Gorakhpur-273010 Electrode: An electrode is a small piece of metal or other substance that is used to take an electric current to or from a source of power. Electrolyte: Electrolyte is a substance that conducts electric current as a result of dissociation into cations and anions, in a polar solvent. The most familiar electrolytes are acids, bases, and salts, which ionize when dissolved in solvents such as water or alcohol.
    [Show full text]
  • Galvanic Cells 17.5 (Pg
    Making galvanic cells 17.5 (pg. 708 – 711) Purpose: Make a galvanic cell, investigate how it works, and compare the voltage produced by different cells Procecure: 1. Your teacher will explain to you how to read a voltmeter. 2. Obtain a copper plate, a zinc plate, an aluminum plate and some paper towel. Clean each metal plate very well with steel wool. Rinse and dry. 3. Obtain three 250 mL beakers, a 400 mL beaker, a voltmeter, a “U-tube”, four pieces of cotton wool (about half the size of your thumb), two wires (with one alligator clip per wire), and a pair of forceps. Clean the beakers. Label them with tape: Zn(NO3)2, Cu(NO3)2, and Al(NO3)3. 4. Into each beaker place about 125 mL of the appropriate solution (according to beaker labels). 5. Rest the U-tube in a 400 mL beaker so that the ends of the tube face up. Fill the tube all the way to the ends with KNO3 solution. Plug both ends tightly with cotton wool. Ideally the cotton should be flush with the ends of the tube and there should be almost no air in the tube. Eventually the cotton will become wet with KNO3. You have just made a “salt-bridge”. 6. Stand the Cu plate in the Cu(NO3)2 solution, Al in Al(NO3)3 and Zn in Zn(NO3)2. 7. Clip one end of a wire to the Cu plate, plug the other end into the voltmeter. Similarly connect the Zn plate to the voltmeter.
    [Show full text]
  • Ferrocenes and Isoindolines As Reagents for Redox Flow Battery Electrolytes and Moieties in Chromophores, Chelates, and Macrocycles
    @ 2021 Briana R. Schrage ALL RIGHTS RESERVED FERROCENES AND ISOINDOLINES AS REAGENTS FOR REDOX FLOW BATTERY ELECTROLYTES AND MOIETIES IN CHROMOPHORES, CHELATES, AND MACROCYCLES A Dissertation Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Briana R. Schrage August, 2021 FERROCENES AND ISOINDOLINES AS REAGENTS FOR REDOX FLOW BATTERY ELECTROLYTES AND MOIETIES IN CHROMOPHORES, CHELATES, AND MACROCYCLES Briana R. Schrage Dissertation Approved: Accepted: ______________________________ ___________________________ Advisor Department Chair Dr. Christopher J. Ziegler Dr. Christopher J. Ziegler ______________________________ ___________________________ Committee Member Dean of the College Dr. Aliaksei Boika Dr. Joseph Urgo ______________________________ ___________________________ Committee Member Dean of the Graduate School Dr. Claire A. Tessier Dr. Marnie M. Saunders ______________________________ ___________________________ Committee Member Date Dr. Yi Pang ______________________________ Committee Member Dr. Junpeng Wang iii ABSTRACT Although rechargeable battery technology has been around as early as the 1800s, redox flow battery (RFB) technology has a little under five decades of research. The most common and well-studied system is the all-vanadium RFB. To this day there is still no perfect RFB design and many batteries suffer from membrane crossover due to corrosive solvents or electroactive materials. Additionally, the cost of some electrolyte components are expensive, and the materials themselves may be toxic. Recent studies have investigated the use of metallocenes as potential RFB components, particularly ferrocene. The ferrocene scaffold is easily modified and this organometallic unit undergoes a highly reversible redox reaction. Introducing water solubilizing groups to metallocenes can allow for these materials to be used in aqueous RFB devices.
    [Show full text]
  • An Organic Redox Flow Cell‐Inspired Paper‐Based Primary Battery
    Full Papers ChemSusChem doi.org/10.1002/cssc.201903511 An Organic Redox Flow Cell-Inspired Paper-Based Primary Battery Marina Navarro-Segarra+,[a] Perla Patricia Alday+,[a] DavidGarcia,[a] Omar A. Ibrahim,[b] Erik Kjeang,[b] Neus SabatØ,[a, c] and Juan Pablo Esquivel*[a] Aportable paper-basedorganic redox flow primary battery trolytesand provides the advantage to form aneutral or near- using sustainable quinone chemistry is presented. The com- neutralpHasthe electrolytes neutralize at the absorbent pad, pact prototype relies on the capillaryforces of the paper which allows asafe disposal after use. The effectsofthe device matrix to develop aquasi-steadyflow of the reactants through design parameters have been studied to enhance battery fea- apair of porous carbon electrodes withoutthe need of exter- tures such as poweroutput,operational time, and fuel utiliza- nal pumps. Co-laminar capillary flow allows operation Under tion. The device achieves afaradaic efficiency of upto98%, mixed-mediaconditions, in which an alkaline anolyte and an which is the highest reported in acapillary-based electrochem- acidic catholyte are employed. This feature enables higher ical power source, as well as acell capacity of up to 1 2 electrochemical cell voltages during discharge operation and 11.4 AhLÀ cmÀ ,comparable to state-of-the-art large-scale the utilization of awider range of available species and elec- redox flow cells. Introduction The increasing usage of small-sized portable electronic devices properly managed butnowadays is sent away to places in the in recent decades has led to astrong demand forminiaturized world where it can causeenvironmental and health prob- power sources. Moreover, such devices require batteries to be lems.[4] The problem is even more critical when this waste is adaptedtoproduct sizes and form factors that make their re- not even collected properly and ends up in landfillswhere, in cycling even more challenging, since it is much harder to sepa- many cases, it is incinerated.
    [Show full text]