SUPERCAPACITÉS ÉLECTROCHIMIQUES Daniel Bélanger Université du Québec à Montréal belanger.daniel@uqam.ca 15 mars 2013
NUMBER OF PAPERS AND CITATIONS Search on Web of Science with : Electrochemical capacitor
PLAN DU COURS CONTEXTE ÉNERGÉTIQUE-STOCKAGE ACCUMULATEURS & SUPERCAPACITÉ ÉLECTROCHIMIQUE CONCEPTS IMPORTANTS D’ÉLECTROCHIMIE STRUCTURE ET CAPACITÉ DE LA DOUBLE COUCHE MÉTHODES DE CARACTÉRISATION Evaluation de la performance MATÉRIAUX Carbon, Conducting polymers, metal oxides Concept of pseudocapacitance FONCTIONNEMENT Systèmes symétrique et asymétrique
Electricity and heating Transportation CO2 emission by sectors Electricity and heating Transportation Manuf. ind and construction How can we reduce them ? http://www.hbcpnetbase.com//articles/14_15_91.pdf
ENERGY STORAGE SYSTEMS Poizot, Dolhem, Energy Environ. Sci. 2011, 4, 2003.
PSA Peugeot Citroën Start-Stop System Reduce fuel consumption by up to 15%
AVANTAGES DES CONDENSATEURS ÉLECTROCHIMIQUES City Bus-Volvo -Simplified system for a city bus, 220kW NiMH-battery NiMH-battery + EC Battery310 kg EC 280 kg DC/DC 90 kg Total weight 680 kg Battery 1150 kg DC/DC 45 kg Total weight 1195 kg Weight reduction: 43 %
ENERGY STORAGE WITH ELECTRICAL DOUBLE LAYER CAPACITOR AND BATTERY Simon, Gogotsi, Nature Materials, 2008, 7, 845.
ENERGY STORAGE WITH ELECTRICAL DOUBLE LAYER CAPACITOR AND BATTERY Chuck Norris Simon, Gogotsi, Nature Materials, 2008, 7, 845.
JME 70 kJ of Energy 2 MT vehicle moving 19 mph 2 MT mass lifted to 12 ft height 1 tsp sugar 4 g 1 D-cell alkali battery 140 g 22 kF / 2.5 V capacitor 4.6 kg From John Miller, JME Capacitor
ENERGY STORAGE WITH ELECTRICAL DOUBLE LAYER CAPACITOR AND BATTERY E = 0.5 C V2 E= Energy C= Capacitance V= Voltage Simon, Gogotsi, Nature Materials, 2008, 7, 845.
CAPACITOR VACUUM DIELECTRIC OXIDE ELECTROLYTIC Ta2O5, Al2O3 C = e A / d
Accumulateur au plomb
Accumulateur au plomb Importance du « curing » ou mûrissage plaques positives empilées dans une étuve 72h avec fort taux d’humidité Importance de la « formation » charge (formation Pb et PbO2) Pb + PbO2 + H2SO4 Pb + carbone + expandeurs
Chemistry of Lead Acid Batteries When the battery is discharged: Lead (-) combines with the sulfuric acid to create lead sulfate (PbSO4), Pb + SO42- PbSO4 + 2e- Lead oxide (+) combines with hydrogen and sulfuric acid to create lead sulfate and water (H2O). PbO2 + SO42- + 4H+ + 2e- PbSO4 + 2H2O lead sulfate builds up on the electrodes, and the water builds up in the sulfuric acid solution. Global reaction: Pb + PbO2 + 2 H2SO4 2 PbSO4 + 2 H2O Concentration of H2SO4 changes from 5.5 M to 2 M Lead Acid Batteries Consist of: Lead (Pb) electrode (-) Lead oxide (PbO2) electrode (+) Water and sulfuric acid (H2SO4) electrolyte.
Chemistry of Lead Acid Batteries When the battery is charged: The process reverses; lead sulfate combining with water to build up lead and lead oxide on the electrodes. PbSO4 + 2H2O PbO2 + SO42- + 4 H+ + 2e- PbSO4 + 2e- Pb + SO42- Global reaction: 2 PbSO4 + 2 H2O Pb + PbO2 + 2 H2SO4 Lead Acid Batteries Consist of: Lead (Pb) electrode (-) Lead oxide (PbO2) electrode (+) Water and sulfuric acid (H2SO4) electrolyte.
Accumulateur au Pb acide - - 0.36 V Pb/PbSO4 1.69 V PbSO4/PbO2 +
Accumulateur au Pb acide - - 0.36 V Pb/PbSO4 0 V H2 /H+ 1.23 V H2O /O2 1.69 V PbSO4/PbO2 + vs. ENH
Pt/H2SO4(aq)/Pt vs Pb/H2SO4(aq)/PbO2 Platinum Platinum H2SO4 solution H2SO4 solution
Pt/H2SO4(aq)/Pt vs Pb/H2SO4(aq)/PbO2 Platinum Platinum Pb PbO2 H2SO4 solution H2SO4 solution H2SO4 solution H2SO4 solution
ACCUMULATEUR
STRUCTURE D’UN SUPERCONDENSATEUR ÉLECTROCHIMIQUE
CAPACITÉ ÉLECTROCHIMIQUE
CAPACITÉ ÉLECTROCHIMIQUE
DOUBLE LAYER MODELS Helmholtz Gouy-Chapman Cdl = dq/d(Dy)
STRUCTURE OF THE DOUBLE LAYER Models of Grahame and Bockris
STRUCTURE DE LA DOUBLE COUCHE 1/C = 1/CI + 1/CO 1/C = 1/CI 1/C = dH2O/e C= 5 x 8.85 x 10-12 F/m 2.8 x 10-10 m = 16 mF/cm2
CAPACITY FOR CARBON CAPACITY CDL = 20 µF/cm2 with S = 1000 m2/g C = 20 x 10-6 F/cm2 x 1000 m2/g x 104 cm2/m2 = 200 F/g
ACCUMULATEUR/CAPACITÉ ÉLECTROCHIMIQUE
ENERGY STORAGE DEVICES SUPERCAPACITORS Capacitive or pseudocapacitive charge Fast charge/discharge Long operational life > 1 000 000 cycles High power density > 1 kW/kg BATTERIES Faradaic charge Chemical reaction Slow charge/discharge process Shorter operational life High energy density 50-150 Wh/kg
MÉTHODES DE CARACTÉRISATION CELLULE ÉLECTROCHIMIQUE VOLTAMÉTRIE CYCLIQUE CHARGE/DÉCHARGE À COURANT CONSTANT PERFORMANCES ÉNERGIE, PUISSANCE
Cellule
VOLTAMETRIE CYCLIQUE
VOLTAMÉTRIE CYCLIQUE- Électrode capacitive
CALCUL DE LA CAPACITÉ C = QCV/V C= Capacité Qcv = Charge V= Voltage UNITÉS Farad = Coulombs/Volt Imoyen = 45 mA V = 2.25 V Vitesse de balayage = 225 mV/s Masse = 10 mg C = 20 F/g
CHARGE/DÉCHARGE À COURANT CONSTANT
COURBE CHARGE/DÉCHARGE CAPACITÉ => Inverse de la pente
CHARGE ET CAPACITÉ I x t (C)
COULOMBIC EFFICIENCY, CE Qdischarge x 100 Qcharge CE (%) =
COULOMBIC EFFICIENCY, CE Qdischarge x 100 Qcharge CE (%) =
PERFORMANCE Densité d’énergie et de puissance Densité d’énergie, Wh kg-1 Densité de puissance, W kg-1
ELECTROCHEMICAL CAPACITOR Electrolyte Current collector Current collector ACTIVE ELECTRODE MATERIAL
Equivalent Series Resistance (ESR) CONTRIBUTION TO ESR -ELECTRONIC RESISTANCE OF THE ELECTRODE MATERIAL -INTERFACIAL RESISTANCE – ELECTRODE/CURRENT COLLECTOR -IONIC DIFFUSION RESISTANCE OF IONS MOVING IS SMALL PORES -ELECTROLYTE RESISTANCE -IONIC RESISTANCE OF IONS MOVING THROUGH THE SEPARATOR
COMPOSANTS D’UN SUPERCONDENSATEUR ÉLECTROCHIMIQUE MATÉRIAUX D’ÉLECTRODES Carbones, Oxydes, Polymères conducteurs Fabrication de l’électrode (additifs) ÉLECTROLYTE Aqueux, Non-aqueux, Liquide ionique COLLECTEUR DE COURANT SÉPARATEUR
EC-Areas of research Electrolyte -Aqueous -Non-aqueous -Ionic liquid Current collector: Surface treatment Electrode materials: Carbon Conducting polymers Metal oxides
TECHNOLOGY PERFORMANCE COST STABILITY/SAFETY
MATÉRIAUX D’ÉLECTRODES
MATERIALS-CAPACITANCE E = 0.5 CV2 K. Naoi, P. Simon, Interface, 2008, 17, 34
CARBONE SURFACE SPÉCIFIQUE ACTIVATION Température élevée COÛT
ELECTROCHEMICAL CAPACITOR Symmetrical cell with 2 identical electrodes
PROPERTIES OF ACTIVATED CARBONS Pore of activated carbon Double-layer capacitance of some carbons Larger than 500Å Smaller than 20Å 20Å ~ 500Å Most surface area is composed of micropores ( more than 90%) Micropores are likely to contribute the most to the energy storage
CAPACITANCE – SURFACE AREA
EFFECT OF PORE SIZE OF THE CARBON ELECTRODE (CH3CH2)4N+ Diameter Desolvated: 0.68 nm Solvated; 1.33 nm BF4- Desolvated: 0.48 nm Solvated: 1.16 nm
FARADAIC PROCESS => Electron transfer [Fe(CN)6]3- + e- <==> [Fe(CN)6]4- PbSO4 + 2 H2O <==> PbO2 + 4 H+ + SO42- + 2 e-
CAPACITÉ ET PSEUDOCAPACITÉ Transfert d’électron à l’interface électrode/électrolyte Cpseudo = 10 to 100 Cdl
PSEUDOCAPACITÉ
PSEUDOCAPACITÉ
MANGANESE DIOXIDE, MnO2 Thin film Composite 0.1 M Na2SO4/H2O @ 5 mV/s
CHARGE STORAGE MECHANSIM FOR MANGANESE DIOXIDE Mn4+/3+ MnO2 + H+ + e- <=====> MnOOH MnO2 + C+ + e- <=====> MnOOC Mn = no change (MnO2)surface + C+ + e- <=====> (MnO2-C+) surface CHARGE STORAGE-CRISTALINITY
THIN ‘’FILM’’ ELECTRODE XPS-Mn 3s Pt/MnO2 Mn(III) Na2SO4 0.1 M Mn(IV) Toupin, Brousse and Bélanger, Chem. Mat. 2004, 16, 3184.
STRUCTURE-CAPACITANCE RELATIONSHIP CAPACITANCE vs. SURFACE AREA for Manganese Dioxide Brousse et al. J. Electrochem. Soc. 2006, 153, A2171.
Capacitive behaviour of MnO2 0.1M Na2SO4 - 2 mV/s MnO2/PTFE/AB/graphite (forte polarisation en absence de carbone) Fenêtre électrochimique 0,9-1V Capacité ~ 150 F/g qcharge/qdécharge100 % (bonne réversibilité des processus électrochimiques)
MAXIMIZE UTILIZATION C+= Li+, Na+, K+, H+ Mn4+ Mn3+ MnO2 C Binder e- Low ionic conductivity Low electronic conductivity Increase ionic conductivity Increase electronic conductivity Carbon MnO2 Binder
ELECTROCHEMICAL UTILIZATION OF MnO2 Mass of MnO2 (mg/cm2) Electrode thickness (µm) Qcv/Qtheo 3 281 12.9 15-16 290 13.0 30-34 555 12.2 45 596 12.5
POLYMÈRES CONDUCTEURS
Electrochemistry of conducting polymers p-doping p-dedoping - + -e- Solution p-dedoping n-doping - +e- + Polymer
POLYTHIOPHENE DERIVATIVE -0.008 -0.006 -0.004 -0.002 0.002 0.004 0.006 0.008 -2.5 -2 -1.5 -1 -0.5 0.5 1 Current (A) Potential (V/(Ag/Ag + )) P- n-doping n-undoping + Et4N+ P p-doping p-undoping BF4- P+
GALVANOSTATIC CHARGE/DISCHARGE CYCLING PFPT/PFPT Cut-off voltages: 1.6 to 2.8 ; 3.0 and 3.2 V ICh = IDch = 2 mA/cm2 in 1 M Et4NBF4/ACN DE Potentiel de cellule (V) Courant (A) DE’ Temps (s) Potentiel (V vs. Ag/Ag+)
MODE DE FONCTIONNEMENT Cellule symétrique Cellule asymétrique
SYSTÈME SYMÉTRIQUE NÉGATIVE POSITIVE
CARBON-BASED ELECTROCHEMICAL CAPACITORS Potential Current Charge
CARBON-BASED ELECTROCHEMICAL CAPACITORS Voltammetric Charge = QCV Potential Current Discharge
CARBON-BASED ELECTROCHEMICAL CAPACITORS QCV (ox) Potential Current QCV (red) Voltammetric charge = QCV
50% of the carbon is unemployed!
50% of the carbon is unemployed! Qdischarge (-) = 0.5 QCV (ox) Qdischarge (+) = 0.5 QCV (red)
(weight of both electrodes) CAPACITANCE OF A CELL Single electrode capacitance C+ = C- = 100 F/g Capacitance of a cell (weight of both electrodes) 25 F/g
CARBON/CARBON NON-AQUEOUS ELECTROLYTE AQUEOUS ELECTROLYTE CELL VOLTAGE = 3 V AQUEOUS ELECTROLYTE -CELL VOLTAGE = 1 V Can an electrochemical capacitor have a cell potential > 1 V?
SYSTÈME HYBRIDE
CARBON/MnO2 J. Long, D. Bélanger, T. Brousse, W. Sugimoto, M.B. Sassin, O. Crosnier Asymmetric electrochemical capacitors—Stretching the limits of aqueous electrolytes MRS Bulletin, 2011, 36, 523
SYSTÈME HYBRIDE Carbone/MnO2 MnO2/MnO2
CARBON/MnO2
CHARGE/DISCHARGE CURVES Carbon/MnO2 MnO2/MnO2
Symétrique vs Asymétrique- Effet du potentiel de cellule
SYSTÈME CARBONE/OXYDE DE PLOMB ÉLECTROLYTE: ACIDE SULFURIQUE C/H2SO4/PbO2