Electrochemical Supercapacitors in F.E.E.Lab

Transcription

1 Electrochemical Supercapacitors in F.E.E.Lab Keryn Lian Department of Materials Science and Engineering University of Toronto

2 Power Density (W/kg) Supercapacitors and Applications Electrodes 1E+06 From Maxwell Web 1E+05 Capacitors 1E+04 1E+03 1E+02 Ultracapacitors 1E+01 Batteries Fuel cells Electrolyte/ separator 1E Energy Density (Wh/kg) エネルギーストレージシステム John R. Miller and Andrew F. Burke, The Electrochemical Society Interface. Spring From Prof. K. Noai US DOE workshop 2

3 Efforts on Electrochemical Capacitor (EC) 1. Modification of Carbon electrodes 1. Activated Carbon, CNT, graphite nanofibers and onion-like carbon characterization and chemical modification (Prof. Gogotsi, Drexel ) 2. Direct formation of TiNx 2. Solid Polymer Electrolytes 1. Solid proton conducting electrolytes for thin, flexible devices 2. Ionic liquid/polymer for high voltage window. 3. Hybrid Device &System 1. Super thin and flexible symmetrical and asymmetrical EC cells 2. ANN battery and hybrid cycle life prediction (Prof. Weigert, MST) 3. Simulation of devices life and thermal properties (Prof. Dawson, ECE, UT) 4. Hybrid EC with battery, photovoltaic for selfpower and for extending power/energy efficiency (Prof. Kherani, ECE, UT). Solar Cell Battery Electrochemical Capacitor (EC) Load 3

4 New Advances in Proton Conducting Polymer Electrolytes and their Applications in Ultrahigh Rate Solid Electrochemical Capacitors Keryn Lian Department of Materials Science and Engineering University of Toronto

5 Outline Background Ultra-high-rate Solid Electrochemical Capacitors (EC) Heteropolyacid (HPA) as proton conducting electrolytes Solid Proton Conducting Polymer Electrolytes Solid symmetric ECs Metallic ECs Double Layer ECs Pseudocapacitve ECs Expansion of Cell Voltage Alternative Electrolytes Asymmetric Multicell-in-one package Summary Key words: high rate, solid/flexible 5

6 State-of-the-Art High Rate ECs Fast device response, small time constant, high power density Onion-like carbon 1 Et 4 NBF 4 /propylene carbonate Graphene nanosheets 2 KOH Reduced graphene oxide 3 KOH 0.9 mf/cm 2 90 µf/cm 2 (120 Hz) 0.3 mf/cm 2 Laser scribed graphene 4 H 3 PO mf/cm 2 (10V/s) Advanced electrodes Liquid electrolytes? Our goal Flexible/rollable EC devices 1. D. Pech, et.al, Nature Nanotechnology 5 (2010) J.R. Miller, et.al, Science 329 (2010) K. Sheng, et.al Scientific Reports 2 (2012). 4. M.F. El-Kady, et.al., Science 335 (2012)

7 Voltage (V) Battery Capacitor Hybrid System The thin and flexible ultracapacitor can have various form factor It can be readily combined with the energy sources 2.5 A Pulse, Peak Power > 2.25 W 3.6 A Pulse, Peak Power > 3.4 W EC+Battery hybrid 1.3 EC+Battery hybrid Battery only Battery only time (min) time (min) 7

8 Solid State ECs polymer electrolytes Current polymer electrolyte Liquid Electrolyte Polymer Electrolyte To eliminate metal cans and separators to form flexible dry ECC multicell in one package ELECTRODE SOLID ELECTROLYTE BiPOLAR ELECTRODE SOLID ELECTROLYTE ELECTRODE 8

9 Solid Electrochemical Capacitors RuO 2 based solid 10-cell EC 10 V/s K. Lian et.al. US Patent, 5,587,872, (1996) M. El-Kady, et al. Science, 335, 1326 (2012) Polymer Electrolytes: Yuan et.al, ACS Nano 6(1) 656 (2012) PVA-H 3 PO 4 9

10 I (A*cm -2 ) Heteropolyacid (HPA) High ionic conductivity at solid state Low cost Less aggressive chemistry Have been considered in fuel cells and sensors H 3 PW 12 O 40.29H 2 O H 3 PMo 12 O 40.29H 2 O H 4 SiW 12 O 40.28H 2 O Proton conductivity (S/cm) Bare MWCNT 2. Single PMo E (V) vs. Ag/AgCl 10

11 Voltage Operation Window of HPA SITA-GRAPHITE-ELECTRODE(-02-1)_Cy04.cor H2SO4-GRAPHITE-ELECTRODE(13)_Cy04.cor PTA-GRAPHITE-ELECTROD(-02-1)E_Cy04.cor H 2 SO 4 SiWA PWA 2 I (Amps/cm ) Dependence of the 1 st one - e - reduction pontntials on the negative charge: 1) XW 12 O 40 n- and 2) XV 12 O 40 n E (V) vs. Ag/AgCl *Altenau et.al, Inorg. Chem., 14, 417, (1975) Lian et al. Electrochem. Solid-State Letters, 11(9) A

12 I (Amps/cm 2 ) I (Amps/cm 2 ) Graphite cell with H 2 SO 4, PWA and SiWA (EDLC) 0.3 M solution; Sweep Rate = 100 mv/s GRAPHITE CELL-H 2 SO 4 GRAPHITE CELL-PWA GRAPHITE CELL-SIWA RuO 2 CELL-H 2 SO 4 RuO 2 CELL-PWA RuO 2 CELL-SiWA E (V) E (V) Lian et al. Electrochemical and Solid-State Letters, 11(9) A158 (2008) Lian

13 Issues and Approaches Issues of HPAs: Poor film forming Often, HPA are pressed as pellets Soluble in water Sensitive to moisture and temperature A good solid electrolyte should possess: High ionic conductivity at all temperature range High stability and shelf life Our Approach: Composite with polymer to immobilize the HPAs Additives 13

14 Composition of Polymer Electrolytes Our polymer electrolytes are comprised of 3 functional components: Polymer matrix: Polyvinyl alcohol (PVA) Ionic conductor: Heteropoly acid Silicotungstic acid H 4 SiW 12 O 40.28H 2 O (SiWA) Additives: Glutaraldehyde Silica oxide Phosphoric acid 14

15 HPA - Polymer Systems HPA + additives + Polyvinyl alcohol (>90 wt.%) (<10 wt.%) Lower HPA sensitivity on environment Form thin film electrolyte Achieve better electrode/electrolyte contact Gen I SiWA + PVA Gen II SiWA + H 3 PO 4 + PVA Gen III SiWA + H 3 PO 4 + Crosslinked-PVA (XL-PVA) 15

16 Cell Assembly Electrode (Stainless steel foils or RuO2 on Ti foils) Pressure and temperature Electrolyte coating PVA-SiWA-H 3 PO 4 Hot-pressing 90 o C Film lamination Electrode area 0.8 cm 2 Electrolyte thickness 50 μm Cell thickness 0.2 mm 16

17 Proton Conductivity of the Polymer Electrolytes Stainless Electrodes 17

18 Conductivity (S cm -1 ) Conductivity of Polymer Electrolytes Stainless steel electrodes Measured in ambient condition SS Poly electrolyte SS SiWA Gen III (SiWA-H 3 PO 4 -XL-PVA) Gen II (SiWA-H 3 PO 4 -PVA) Gen I (SiWA-PVA) Day 18

19 ln (conductivity) (Scm -1 ) 0 o C to 50 o C at 50% RH Arrhenius plot No cross-linking Cross-linked (solid polymer) -4.8 R 2 = /T (K -1 ) 14.8 kj/mol R 2 = kj/mol Proton hopping in crystalline material H. Gao, K. Lian, Journal of Materials Chemistry, 22 (2012)

20 Conductivity (S cm -1 ) Conductivity and Stability (Comparison with Nafion ) SS SiWA-H 3 PO 4 -PVA cell Nafion cell Poly electrolyte SS Days H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012) 20

21 Intensity (a.u.) Intensity (a.u.) Intensity (a.u.) Structural Analyses (XRD) (cont) Hydration Dehydration Keggin crystal structure HPA-PVA No cross-linking (solid) Cross-linked HPA-XLPVA 10 - (solid-polymer) (solid) Cross-linked HPA-XLPVA 10 - (gel-polymer) (gel) No long range order & crystal structure Theta H. Gao, K. Lian, Journal of Materials Chemistry, 22 (2012)

22 Solid ECs Metallic electrode EDLC electrode Pseudocapacitive electrode Stainless steel Graphite RuO 2, Mo x N 22

23 Current density (Acm -2 ) Solid Metallic EDLC ,000 V/s H 2 SO 4 HPA-XLPVA Nafion SS electrolyte SS Cell voltage (V) H. Gao, K. Lian, Journal of Materials Chemistry, (2012) 23

24 Current density (A cm -2 ) Current density (A cm -2 ) SiWA + H 3 PO 4 + PVA vs. Nafion Both solid EC devices are tested at an Ultra high Rate of 5000 V/s Day 1 Day (a) Day 1 Nafion cell SiWA-H 3 PO 4 -PVA cell (b) Day 14 Nafion cell SiWA-H 3 PO 4 -PVA cell Cell voltage (V) Cell voltage (V) Polymer electrolyte) have exceeded Nafion in stability. H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012) 24

25 Current density (Acm -2 ) Current density (Acm -2 ) Current density (Acm -2 ) Current density (Acm -2 ) Solid Graphite EDLC Vs Vs mf/cm Vs -1 Cell voltage (V) Cell voltage (V) Vs mf/cm Cell voltage (V) H. Gao, K. Lian, Journal of Materials Chemistry, (2012) Cell voltage (V) 25

26 C' (Fcm -2 ) Cell voltage (V) C'' (Fcm -2 ) Graphite EDLC: Charge-discharge & EIS ms C' C'' Frequency 0.0 (Hz) Time (s) 5 ma/cm 2, 2.6 mf/cm 2 26

27 Cell voltage (V) C' (Fcm -2 ) C'' (Fcm -2 ) Current density (Acm -2 ) Current density (Acm -2 ) RuO 2 Solid pseudocapacitor Vs Vs mf/cm 2 10 mf/cm Cell voltage (V) 8.3 ma/cm 2, 32 mf/cm ms Cell voltage (V) C' C'' Time (s) Frequency (Hz) 27

28 Solid vs. Liquid Mo x N EC Cell Sweep rate = 1 V/s Sweep rate = 10 V/s H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013) 28

29 Solid EC Cell at High Rates Sweep rate = 50 V/s Sweep rate = 100 V/s H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013) 29

30 Solid vs. Liquid EC Cell EIS Analyses H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013) 30

31 Voltage Window Expansion Organic or Ionic Liquid Polymer Electrolytes. Asymmetric Cell Multi-cell-in-One package 31

32 Asymmetrical Polymer-based Capacitor Electrode active materials coated on substrate Activated/modified carbon Mixed metal oxides Conductive polymers CNT Electrolyte coated on electrode active material Polymer/acid gel blends Thin film polymer electrolyte 30 to 50 m 32

33 Fabrication of Solid Asymmetric Cell Film conductivity 0.01 S/cm Thickness mm Pressure and temperature 33

34 I (Amps/cm 2 ) E (Volts) Solid Asymmetric Ecs (graphite-ruo 2 ) GRAPHITE-PTA (14)-DAY1.cor GRAPHITE-PTA (14)-DAY4-CHARGE-DISCHARGE-100.cor E (Volts) Time (Sec) K. Lian et.al, Electrochemistry Communications 12(4) 517 (2010) 34

35 Solid multi-cell-in-one package ECs Multi-cell EC in single package Two ECs in series (bipolar plate) Smaller device capacitance Higher cell voltage window Polymer electrolyte Terminal electrode Terminal electrode Bipolar electrode Lian Oct

36 Current density (A cm -2 ) Solid Metallic 2-cell-in-1 EC Cycle No. 100 Cycle No. 20,000 At 5,000 V/s scan rate SS Poly electrolyte SS Poly electrolyte SS Cell voltage (V) Increased voltage window and excellent cycle life H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012) 36

37 Current density (Acm -2 ) Current density (Acm -2 ) Solid Carbon Based 2-cell-in-1 EDLC Single Cell 2-Cell-in-1 package Vs Vs Cell voltage (V) Cell voltage (V) Electrodes: Graphite on Stainless Steel foils 37

38 Current density (Acm -2 ) Current density (Acm -2 ) Current density (Acm -2 ) Current density (Acm -2 ) Solid Carbon Based 2-cell-in-1 EDLC Vs Vs Vs -1 Cell voltage (V) Vs -1 Cell voltage (V) Cell voltage (V) Cell voltage (V) 38

39 C' (mf cm -2 ) C'' (mf cm -2 ) Solid Carbon Based 2-cell EC (Impedance) Frequency (Hz) Single cell Multi-cell Frequency (Hz) Single cell Multi-cell 39

40 Latest: Alkaline based solid electrolyte 50C to -10C Rate: 2000 V/s 40

41 Summary SiWA - H 3 PO4 PVA electrolytes have been shown to 1. perform equal or better than liquid aqueous electrolyte; 2. be applicable for both EDLC and pseudocapacitors. 3. store and deliver charge at ultrahigh rates; 4. retain its conductivity and ultrahigh rate capability over time, yielding excellent shelf and cycle life; 5. enable multi-cell ECs in single package without sacrificing rate capability. Solid polymer electrolytes are viable for high rate and high power energy storage devices. 41

42 Electrolytes: Acknowledgement Han Gao, Sanaz Ketabi, Haoran Wu, Jak Li, Alex Dilio and Blair Decker Electrodes Gurvinder Bajwa, Fred Xiao, Matt Genovece, Terence Lee Applications Jin Chang, Ahmed Huzayin, Bernie Ting, NSERC Canada Ontario Research Fund Ontario Center of Excellence University of Toronto 42