Chapter 13: Electrochemical Cells
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Electrolyte Panel
Lab Dept: Chemistry Test Name: ELECTROLYTE PANEL General Information Lab Order Codes: LYTE Synonyms: Electrolytes; Lytes CPT Codes: 80051 – Electrolyte panel Test Includes: Carbon Dioxide, Chloride, Potassium, Sodium concentrations reported in mEq/L, and AGAP (Anion Gap). Logistics Test Indications: The maintenance of osmotic pressure and water distribution in the various body fluid compartments is primarily a function of the four major electrolytes, Na+, K+, Cl-, and HCO3-. In addition to water homeostasis, these electrolytes play an important part in the maintenance of pH, regulation of proper heart and muscle functions, involvement in electron transfer reactions, and participation in catalysis as cofactors for enzymes. Lab Testing Sections: Chemistry Phone Numbers: MIN Lab: 612-813-6280 STP Lab: 651-220-6550 Test Availability: Daily, 24 hours Turnaround Time: 30 minutes Special Instructions: N/A Specimen Specimen Type: Blood Container: Green top (Li Heparin) tube, preferred Alternate tube: Red, marble or gold top tube Draw Volume: 0.6 mL blood Processed Volume: 0.2 mL serum/plasma Collection: Routine blood collection. Mix tubes containing anticoagulant by gentle inversion. Note: Venipuncture samples are preferred, but capillary specimens will be accepted. Special Processing: Lab Staff: Sample must be run within one hour of collection for CO2 stability. Centrifuge specimen, remove serum/plasma aliquot into a plastic sample cup. Avoid prolonged contact with separated cells. Store at refrigerated temperatures. Patient Preparation: None Sample Rejection: Mislabeled or unlabeled specimens Interpretive Reference Range: See individual analyte procedures Critical Values: See individual analyte procedures Limitations: See individual analyte procedures Methodology: See individual analyte procedures References: See individual analyte procedures Updates: 2/8/2016: Update alt tube types . -
Electrochemical Cells
Electrochemical cells = electronic conductor If two different + surrounding electrolytes are used: electrolyte electrode compartment Galvanic cell: electrochemical cell in which electricity is produced as a result of a spontaneous reaction (e.g., batteries, fuel cells, electric fish!) Electrolytic cell: electrochemical cell in which a non-spontaneous reaction is driven by an external source of current Nils Walter: Chem 260 Reactions at electrodes: Half-reactions Redox reactions: Reactions in which electrons are transferred from one species to another +II -II 00+IV -II → E.g., CuS(s) + O2(g) Cu(s) + SO2(g) reduced oxidized Any redox reactions can be expressed as the difference between two reduction half-reactions in which e- are taken up Reduction of Cu2+: Cu2+(aq) + 2e- → Cu(s) Reduction of Zn2+: Zn2+(aq) + 2e- → Zn(s) Difference: Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(aq) - + - → 2+ More complex: MnO4 (aq) + 8H + 5e Mn (aq) + 4H2O(l) Half-reactions are only a formal way of writing a redox reaction Nils Walter: Chem 260 Carrying the concept further Reduction of Cu2+: Cu2+(aq) + 2e- → Cu(s) In general: redox couple Ox/Red, half-reaction Ox + νe- → Red Any reaction can be expressed in redox half-reactions: + - → 2 H (aq) + 2e H2(g, pf) + - → 2 H (aq) + 2e H2(g, pi) → Expansion of gas: H2(g, pi) H2(g, pf) AgCl(s) + e- → Ag(s) + Cl-(aq) Ag+(aq) + e- → Ag(s) Dissolution of a sparingly soluble salt: AgCl(s) → Ag+(aq) + Cl-(aq) − 1 1 Reaction quotients: Q = a − ≈ [Cl ] Q = ≈ Cl + a + [Ag ] Ag Nils Walter: Chem 260 Reactions at electrodes Galvanic cell: -
3 PRACTICAL APPLICATION BATTERIES and ELECTROLYSIS Dr
ELECTROCHEMISTRY – 3 PRACTICAL APPLICATION BATTERIES AND ELECTROLYSIS Dr. Sapna Gupta ELECTROCHEMICAL CELLS An electrochemical cell is a system consisting of electrodes that dip into an electrolyte and in which a chemical reaction either uses or generates an electric current. A voltaic or galvanic cell is an electrochemical cell in which a spontaneous reaction generates an electric current. An electrolytic cell is an electrochemical cell in which an electric current drives an otherwise nonspontaneous reaction. Dr. Sapna Gupta/Electrochemistry - Applications 2 GALVANIC CELLS • Galvanic cell - the experimental apparatus for generating electricity through the use of a spontaneous reaction • Electrodes • Anode (oxidation) • Cathode (reduction) • Half-cell - combination of container, electrode and solution • Salt bridge - conducting medium through which the cations and anions can move from one half-cell to the other. • Ion migration • Cations – migrate toward the cathode • Anions – migrate toward the anode • Cell potential (Ecell) – difference in electrical potential between the anode and cathode • Concentration dependent • Temperature dependent • Determined by nature of reactants Dr. Sapna Gupta/Electrochemistry - Applications 3 BATTERIES • A battery is a galvanic cell, or a series of cells connected that can be used to deliver a self-contained source of direct electric current. • Dry Cells and Alkaline Batteries • no fluid components • Zn container in contact with MnO2 and an electrolyte Dr. Sapna Gupta/Electrochemistry - Applications 4 ALKALINE CELL • Common watch batteries − − Anode: Zn(s) + 2OH (aq) Zn(OH)2(s) + 2e − − Cathode: 2MnO2(s) + H2O(l) + 2e Mn2O3(s) + 2OH (aq) This cell performs better under current drain and in cold weather. It isn’t truly “dry” but rather uses an aqueous paste. -
Elements of Electrochemistry
Page 1 of 8 Chem 201 Winter 2006 ELEM ENTS OF ELEC TROCHEMIS TRY I. Introduction A. A number of analytical techniques are based upon oxidation-reduction reactions. B. Examples of these techniques would include: 1. Determinations of Keq and oxidation-reduction midpoint potentials. 2. Determination of analytes by oxidation-reductions titrations. 3. Ion-specific electrodes (e.g., pH electrodes, etc.) 4. Gas-sensing probes. 5. Electrogravimetric analysis: oxidizing or reducing analytes to a known product and weighing the amount produced 6. Coulometric analysis: measuring the quantity of electrons required to reduce/oxidize an analyte II. Terminology A. Reduction: the gaining of electrons B. Oxidation: the loss of electrons C. Reducing agent (reductant): species that donates electrons to reduce another reagent. (The reducing agent get oxidized.) D. Oxidizing agent (oxidant): species that accepts electrons to oxidize another species. (The oxidizing agent gets reduced.) E. Oxidation-reduction reaction (redox reaction): a reaction in which electrons are transferred from one reactant to another. 1. For example, the reduction of cerium(IV) by iron(II): Ce4+ + Fe2+ ! Ce3+ + Fe3+ a. The reduction half-reaction is given by: Ce4+ + e- ! Ce3+ b. The oxidation half-reaction is given by: Fe2+ ! e- + Fe3+ 2. The half-reactions are the overall reaction broken down into oxidation and reduction steps. 3. Half-reactions cannot occur independently, but are used conceptually to simplify understanding and balancing the equations. III. Rules for Balancing Oxidation-Reduction Reactions A. Write out half-reaction "skeletons." Page 2 of 8 Chem 201 Winter 2006 + - B. Balance the half-reactions by adding H , OH or H2O as needed, maintaining electrical neutrality. -
All-Carbon Electrodes for Flexible Solar Cells
applied sciences Article All-Carbon Electrodes for Flexible Solar Cells Zexia Zhang 1,2,3 ID , Ruitao Lv 1,2,*, Yi Jia 4, Xin Gan 1,5 ID , Hongwei Zhu 1,2 and Feiyu Kang 1,5,* 1 State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China; [email protected] (Z.Z.); [email protected] (X.G.); [email protected] (H.Z.) 2 Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China 3 School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830046, Xinjiang Province, China 4 Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094, China; [email protected] 5 Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong Province, China * Correspondences: [email protected] (R.L.); [email protected] (F.K.) Received: 16 December 2017; Accepted: 20 January 2018; Published: 23 January 2018 Abstract: Transparent electrodes based on carbon nanomaterials have recently emerged as new alternatives to indium tin oxide (ITO) or noble metal in organic photovoltaics (OPVs) due to their attractive advantages, such as long-term stability, environmental friendliness, high conductivity, and low cost. However, it is still a challenge to apply all-carbon electrodes in OPVs. Here, we report our efforts to develop all-carbon electrodes in organic solar cells fabricated with different carbon-based materials, including carbon nanotubes (CNTs) and graphene films synthesized by chemical vapor deposition (CVD). Flexible and semitransparent solar cells with all-carbon electrodes are successfully fabricated. -
A Review of Cathode and Anode Materials for Lithium-Ion Batteries
A Review of Cathode and Anode Materials for Lithium-Ion Batteries Yemeserach Mekonnen Aditya Sundararajan Arif I. Sarwat IEEE Student Member IEEE Student Member IEEE Member Department of Electrical & Department of Electrical & Department of Electrical & Computer Engineering Computer Engineering Computer Engineering Florida International University Florida International University Florida International University Email: [email protected] Email: [email protected] Email: [email protected] Abstract—Lithium ion batteries are one of the most technologies such as plug-in HEVs. For greater application use, commercially sought after energy storages today. Their batteries are usually expensive and heavy. Li-ion and Li- based application widely spans from Electric Vehicle (EV) to portable batteries show promising advantages in creating smaller, devices. Their lightness and high energy density makes them lighter and cheaper battery storage for such high-end commercially viable. More research is being conducted to better applications [18]. As a result, these batteries are widely used in select the materials for the anode and cathode parts of Lithium (Li) ion cell. This paper presents a comprehensive review of the common consumer electronics and account for higher sale existing and potential developments in the materials used for the worldwide [2]. Lithium, as the most electropositive element making of the best cathodes, anodes and electrolytes for the Li- and the lightest metal, is a unique element for the design of ion batteries such that maximum efficiency can be tapped. higher density energy storage systems. The discovery of Observed challenges in selecting the right set of materials is also different inorganic compounds that react with alkali metals in a described in detail. -
Reaction Engineering of Polymer Electrolyte Membrane Fuel Cells
Reaction Engineering of Polymer Electrolyte Membrane Fuel Cells A new approach to elucidate the operation and control of Polymer Electrolyte Membrane (PEM) fuel cells is being developed. A global reactor engineering approach is applied to PEM fuel cells to identify the essential physics that govern the dynamics in PEM fuel cells. Reaction engineering principles are employed to develop a one-dimensional differential PEM fuel cell suitable for elucidating the dynamic performance of PEM cells under well-defined conditions. Polymer Electrolyte Fuel Cells Polymer electrolyte membrane (PEM) fuel cells employ a polymer membrane with acid side groups to conduct protons from the anode to cathode. Water management in the fuel cell is critical for PEM fuel cell operation. Sufficient water must be absorbed into the membrane to ionize the acid groups; excess water can flood the cathode of the fuel cell diminishing fuel cell performance limiting the power output. A schematic of a polymer electrolyte membrane hydrogen-oxygen fuel cell is shown in Figure 1. load e- Figure 1. Hydrogen-oxygen PEM fuel cell. Hydrogen molecules hydrogen in oxygen in dissociatively adsorb at the anode and are oxidized to protons. Electrons travel through an external load resistance. Protons diffuse H+ through the PEM under an e t electrochemical gradient to the y l ro t c cathode. Oxygen molecules adsorb e l at the cathode, are reduced and react hydrogen r E oxygen e m y + water out with the protons to produce water. + water out l Po The product water is absorbed into the PEM, or evaporates into the gas anode cathode streams at the anode and cathode. -
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 . -
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 . -
Advances in Materials Design for All-Solid-State Batteries: from Bulk to Thin Films
applied sciences Review Advances in Materials Design for All-Solid-state Batteries: From Bulk to Thin Films Gene Yang 1, Corey Abraham 2, Yuxi Ma 1, Myoungseok Lee 1, Evan Helfrick 1, Dahyun Oh 2,* and Dongkyu Lee 1,* 1 Department of Mechanical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC 29208, USA; [email protected] (G.Y.); [email protected] (Y.M.); [email protected] (M.L.); [email protected] (E.H.) 2 Chemical and Materials Engineering Department, Charles W. Davidson College of Engineering, San José State University, San José, CA 95192-0080, USA; [email protected] * Correspondence: [email protected] (D.O.); [email protected] (D.L.) Received: 15 June 2020; Accepted: 7 July 2020; Published: 9 July 2020 Featured Application: All solid-state lithium batteries, all solid-state thin-film lithium batteries. Abstract: All-solid-state batteries (SSBs) are one of the most fascinating next-generation energy storage systems that can provide improved energy density and safety for a wide range of applications from portable electronics to electric vehicles. The development of SSBs was accelerated by the discovery of new materials and the design of nanostructures. In particular, advances in the growth of thin-film battery materials facilitated the development of all solid-state thin-film batteries (SSTFBs)—expanding their applications to microelectronics such as flexible devices and implantable medical devices. However, critical challenges still remain, such as low ionic conductivity of solid electrolytes, interfacial instability and difficulty in controlling thin-film growth. In this review, we discuss the evolution of electrode and electrolyte materials for lithium-based batteries and their adoption in SSBs and SSTFBs. -
Demonstrating Solar Conversion Using Natural Dye Sensitizers
Demonstrating Solar Conversion Using Natural Dye Sensitizers Subject Area(s) Science & Technology, Physical Science, Environmental Science, Physics, Biology, and Chemistry Associated Unit Renewable Energy Lesson Title Dye Sensitized Solar Cell (DSSC) Grade Level (11th-12th) Time Required 3 hours / 3 day lab Summary Students will analyze the use of solar energy, explore future trends in solar, and demonstrate electron transfer by constructing a dye-sensitized solar cell using vegetable and fruit products. Students will analyze how energy is measured and test power output from their solar cells. Engineering Connection and Tennessee Careers An important aspect of building solar technology is the study of the type of materials that conduct electricity and understanding the reason why they conduct electricity. Within the TN-SCORE program Chemical Engineers, Biologist, Physicist, and Chemists are working together to provide innovative ways for sustainable improvements in solar energy technologies. The lab for this lesson is designed so that students apply their scientific discoveries in solar design. Students will explore how designing efficient and cost effective solar panels and fuel cells will respond to the social, political, and economic needs of society today. Teachers can use the Metropolitan Policy Program Guide “Sizing The Clean Economy: State of Tennessee” for information on Clean Economy Job Growth, TN Clean Economy Profile, and Clean Economy Employers. www.brookings.edu/metro/clean_economy.aspx Keywords Photosynthesis, power, electricity, renewable energy, solar cells, photovoltaic (PV), chlorophyll, dye sensitized solar cells (DSSC) Page 1 of 10 Next Generation Science Standards HS.ESS-Climate Change and Human Sustainability HS.PS-Chemical Reactions, Energy, Forces and Energy, and Nuclear Processes HS.ETS-Engineering Design HS.ETS-ETSS- Links Among Engineering, Technology, Science, and Society Pre-Requisite Knowledge Vocabulary: Catalyst- A substance that increases the rate of reaction without being consumed in the reaction. -
Advancing Focused Ion Beam Characterization for Next Generation Lithium-Ion Batteries
UC San Diego UC San Diego Electronic Theses and Dissertations Title Advancing Focused Ion Beam Characterization for Next Generation Lithium-Ion Batteries Permalink https://escholarship.org/uc/item/3sh5k04b Author Lee, Jungwoo Publication Date 2018 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA SAN DIEGO Advancing Focused Ion Beam Characterization for Next Generation Lithium-Ion Batteries A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in NanoEngineering by Jungwoo Zema Lee Committee in charge: Professor Ying Shirley Meng, Chair Professor David P. Fenning Professor Eric E. Fullerton Professor Olivia A. Graeve Professor Ping Liu 2018 Copyright Jungwoo Zema Lee, 2018 All rights reserved. The Dissertation of Jungwoo Zema Lee is approved, and it is acceptable in quality and form for publication on microfilm and electronically: Chair University of California San Diego 2018 iii DEDICATION To my given and chosen family iv TABLE OF CONTENTS Signature Page ..................................................................................................................... iii Dedication ............................................................................................................................ iv Table of Contents ................................................................................................................ v List of Abbreviations .........................................................................................................