Production and Characterization of carbon-free bifunctional cathodes for the use in lithium-air batteries with an aqueous alkaline electrolyte

Transcription

1 Chrt EIA, Borovetz 2014, Norert Wgner Production nd Chrcteriztion of cron-free ifunctionl cthodes for the use in lithium-ir tteries with n queous lkline electrolyte Norert Wgner, Dennis Wittmier, K. Andres Friedrich Germn Aerospce Center (DLR) Pfffenwldring 38-49, Stuttgrt, Germny

2 Chrt EIA, Borovetz 2014, Norert Wgner Presenttion outline Appliction of EIS in ttery reserch t DLR Motivtion Li-ir tteries Electrode production techniques t the DLR Cthode for the Li-ir ttery Ctlyst screening of ifunctionl cthodes (ORR nd OER) Conclusion nd outlook

3 Activities of the Btterietechnik tem Production nd Chrcteristion of cthodes for Lithium-Sulfur nd Lithium-ir tteries Chrcteristion of Li-ion tteries with in-situ nd ex-situ-methods Source: N AT U R E VO L M A R C H

4 EIS mesurement t different SOC Dischrge t 1C (NMC 2,25 Ah) (LiFePO 4 1,1Ah)

5 Discrimintion of SOC nd SOH of seril connected tteries Seril connection V2 Z01 U=3,25V SoH100 Z02 U=3,25V SoH100 Z07 U=3,25V SoH60 i totl (t) Z01 Z02 Z07 Impednce Z / mω Frequency f / Hz Phse ngle ϕ / Z01 Impednce Z Z01 Phse ϕ Z02 Impednce Z Z02 Phse ϕ Z03 Impednce Z Z03 Phse ϕ Z07 Impednce Z Z07 Phse ϕ I Sens û Z01 û Z02 û Z07 î Z01 î Z02 î Z07 Voltge U / mv Current I / ma Frequency f / Hz

6 In-situ XRD nd EIS mesurements during dischrging Li-S tteries N. A. Cñs, S. Wolf, N. Wgner, K. A. Friedrich. J. of Power Sources, 226 (2013)

7 Chrt 7 Presenttion August 2013 Electrochemicl Model of Li-S Bttery Equivlent circuit Model R 0 R 1 -CPE 1 R 2 -CPE 2 Chemicl nd physicl cuse Ohmic resistnce Anode chrge trnsfer Cthode process: chrge trnsfer of sulfur intermedites R 3 -CPE 3 Cthode process: rection nd formtion of S 8 nd Li 2 S R 4 -CPE 4 Diffusion 7

8 Chrt EIA, Borovetz 2014, Norert Wgner Motivtion Why Li-ir tteries? Highest theoreticl specific energy density ( Wh/kg) Cthodic rectnt, O 2 from ir, does not hve to e stored Environmentl friendliness Higher sfety thn Li-ion tteries (only one of the rectnts contined in the ttery) Potentilly longer cycle nd shelf lives

9 Chrt EIA, Borovetz 2014, Norert Wgner Motivtion Why Li-ir tteries? Highest theoreticl specific energy density ( Wh/kg). Cthodic rectnt, O 2 from ir, does not hve to e stored Environmentl friendliness Higher sfety thn Li-ion tteries (only one of the rectnts contined in the ttery) Potentilly longer cycle nd shelf lives G. Girishkumr et l., J. Phys. Chem. Lett., 2010, 1,

10 Chrt EIA, Borovetz 2014, Norert Wgner Schemticlly representtion of Li-ir ttery

11 Chrt EIA, Borovetz 2014, Norert Wgner Architectures of Li-ir Btteries Non-queous electrolyte: 2Li + + O 2 + 2e Li 2 O 2 E rev = 2,959 V 2Li + +2e + (1/2) O 2 Li 2 O E rev = 2,913 V Aqueous electrolyte: 4Li + O 2 + 2H 2 O 4LiOH (lkline medi) E rev = 3,446 V 4Li + O 2 + 4H + 2H 2 O + 4Li + (cidic medi) E rev = 4,274 V

12 Chrt EIA, Borovetz 2014, Norert Wgner Schemticlly representtion of Lithium-Air Bttery with Aqueous Electrolyte Interlyer Lithium Festkörper Solid Li + -conductor Li + -Leiter Rektions Rection - produkte products Aqueous Welectroyte ässrige Elektrolyt solution - lösung O 2 -Reduktion -Reduction Rection eqution (lkline Electrolyte): 4Li + O 2 + 2H 2 O 4LiOH; E = 3,45 V

13 Bi-functionl Oxygen-Electrodes: Design Bi-functionl Oxygen-Electrodes = ctlizes ORR nd OER Ctlyst Depending on mnufctoring process every electrode consists of: Ctlyst(s) Conductive gent (C, Grphit ) Binder (PTFE, PVdF ) Sustrte (Metl mesh, ) Design Porestructure Function BOE Electrolyte Active Surfce Cond. gent Different mnufctoring processes used t DLR: Dry Powder Sprying, Rective Rolling n Mixing, Pressing nd APS

14 Chrt EIA, Borovetz 2014, Norert Wgner Production Techniques -Dry Sprying Technique -Wet Sprying Techniquen - Rective Mixing nd Rolling (RMR) -Screen printing - Rective Mixing Addi t ives C t l yst s M etl net GDE

15 Chrt EIA, Borovetz 2014, Norert Wgner Production Techniques -Dry Sprying Technique -Wet Sprying Techniquen - Rective Mixing nd Rolling (RMR) -Screen printing - Rective Mixing Addi t ives C t l yst s M etl net GDE

16 Chrt EIA, Borovetz 2014, Norert Wgner Dry Powder Sprying Technique memrne roller RMR (Sustrt) Dry spryed lyer coting nozzle powder supporter ctlyst dditive Top view Nitrog en N. Wgner, T. Kz, DE A1, 2002

17 Chrt EIA, Borovetz 2014, Norert Wgner

18 Chrt EIA, Borovetz 2014, Norert Wgner Electricl Circuit e - NOH 30% (H 2 O) Cl 2 O 2 O 2 O O O O e - e - e - O e - Net O H O -2 OH - Ag Silver GDE (ODC) H OH - NOH 2 H 2 O 4 NOH NOH N + N + N + N + Memrne NOH 32% Anode Cl - N + e - NCl solution (Brine)

19 Chrt EIA, Borovetz 2014, Norert Wgner Chlorine production with ODC (Oxygen Depolrised Cthode) Chlorine production unit with ODC technique t Byer in Ürdingen (20,000 t/y) since My 2011

20 CT picture of Silver gs diffusion electrode

21 FIB-TEM picture of Silver gs diffusion electrode

22 Chrt EIA, Borovetz 2014, Norert Wgner Possile production options for multilyer electrodes Li + conducting Memrne Ctlyst lyer 1 (Chnged composition, production conditions nd techniques) Ctlyst Lyer 2 hydrophoic rrier lyer (C PTFE) Ctlyst lyer 1 (Chnged composition, production conditions nd techniques) Ctlyst lyer 2 hydrophoic rrier lyer Composition: chemicl composition (metls nd metl oxides) structure electr. contct O 2 (metl net, fom, porous sustrte, etc.)

23 Chrt EIA, Borovetz 2014, Norert Wgner PTFE-ounded Cron Powder: SEM- picture

24 Chrt EIA, Borovetz 2014, Norert Wgner VPS coted cthode for Li-ir ttery Cro Fer net cotedonesidewith Ag+LSCF other side with C+PTFE

25 Chrt EIA, Borovetz 2014, Norert Wgner Picture of APS-coted porous sustrte with 50 vol. % Ag+50 vol. % LSCF, gs side C/PTFE (dry spryed)

26 Chrt EIA, Borovetz 2014, Norert Wgner CV: with Ag+LSCF (APS, electrolyte side) nd PTFE+C (Dry Powder Sprying, gs side) coted Rhodius-Net in 1 N LiOH, Reference electrode: Hg/HgO Current / ma 20 CV 1 mv/s Air, RT CV 1 mv/s O 2, RT Potentil / mv

27 Chrt EIA, Borovetz 2014, Norert Wgner Atmospheric Plsm Sprying (APS) 0.3M nitrte solution for injection SEM of ctlyst lyer nd cross section plsm spryed t DLR P. Fuchis, J. Phys. D: Appl. Phys. 37 (2004) R86 R108

28 Chrt EIA, Borovetz 2014, Norert Wgner Mnufctoring of ifunctionl gs diffusion electrodes Oxide ctlysts (L 0.6 C 0.4 CoO 3 ) cn e spryed on for exmple Rhodius sustrte with APS Ctlyst lyer Rhodius sustrte Electrodes with nole metl nd other ctlysts cn e mde with dry power sprying technique Ctlyst lyer = ctlyst+cron/ grphite+inder Grphite GDE sustrte or y pressing the ctlyst lyer on for exmple Sigrcet GDL 35 DC with hydrulic press Ctlyst lyer = ctlyst+cron/ grphite+inder Sigrcet GDL35 DC

29 Chrt EIA, Borovetz 2014, Norert Wgner Screening of ifunctionl ctlysts Experimentl Thin ctlyst lyers reduce the influence of the electrode structure Cyclic Voltmmetrie ws crried out t hlf cell with 1M LiOH (q.) nd 25 C nd 50 C Gs O 2, pltinum counter electrode (CE), reversile hydrogen reference electrode (RE) Potentil rnge 0.1V - 1.8V vs. RHE Nole metl ctlyst configurtion Oxide ctlyst configurtion 80 wt % grphite + 20 wt % PTFE + ctlyst Gs 100 wt % ctlyst Gs Electrode Electrode + Sigrcet GDL35 DC

30 Chrt EIA, Borovetz 2014, Norert Wgner Experimentl results Polriztion curves with 1mV s -1 Nole metl ctlysts show good ctivity towrds oxygen reduction rection (ORR) ut poor ctivity towrds oxygen evolution rection (OER) Incresing the temperture shows significnt improvment of ctivity

31 Chrt EIA, Borovetz 2014, Norert Wgner Experimentl results Polriztion curves with 1mV s -1 Oxide ctlysts show more lnced chrcteristics towrds ORR nd OER thn nole metl ctlysts. Compred to their ctivity in ORR they show high ctivity in OER. Incresing the temperture shows significnt improvment of ctivity

32 Chrt EIA, Borovetz 2014, Norert Wgner Impednce Mesurements during ORR in 10 N NOH, on Silver Electrodes t Different Current Densities, i< -50 macm m Z / ma ma ma ma ma ma ma ma ma ma phse / o Z' / 15 ma 50 ma 25 ma 20mA 30 ma 35 ma 40 ma 45 ma 10 ma 5 ma Z'' / 0 100m K 3K 10K 100K frequency / Hz Bode representtion Nyquist representtion

33 Chrt EIA, Borovetz 2014, Norert Wgner 2 Z / Impednce Mesurements during ORR in 10 N NOH, on Silver Electrodes t Different Current Densities, i> -50 macm ma phse / o 90-1 Z' / ma ma m 600m ma ma ma ma ma ma ma 0 100m K 3K 10K 100K frequency / Hz ma 150 ma 100 ma 50 ma 200 ma 250 ma 300 ma 350 ma 400 ma 450 ma Z'' /

34 Chrt EIA, Borovetz 2014, Norert Wgner Electrode Model with cylindricl, homogeneous pores nd complex Frdy-impednce Zq=

35 Chrt EIA, Borovetz 2014, Norert Wgner Evlution of EIS mesured during ORR Equivlent circuit nd R d = f(i) R / 6 L Rel 4 Rct Rpor Rd Cd Cdl current/ma

36 Chrt EIA, Borovetz 2014, Norert Wgner Current density dependency of the chrge trnsfer resitnce R ct 1.6 Rct / current/ma

37 Chrt EIA, Borovetz 2014, Norert Wgner Current density dependency of electrolyte resistnce inside the pore 2.5 pore electrolyte res. / current/ma

38 Chrt EIA, Borovetz 2014, Norert Wgner U-i chrcteristic nd current density dependency of impednce elements R d nd R ct ir-corr. Potentil vs. NHE / V 1,1 1,08 1,06 1,04 1,02 1 0,98 0,96 0,94 0,92 8,00 7,00 6,00 5,00 4,00 3,00 2,00 1,00 Rd; Rct / Ohm 0,9 0,00-0,10-0,08-0,06-0,04-0,02 0,00 Current density / Acm -2

39 Chrt EIA, Borovetz 2014, Norert Wgner Current density dependency of k d, R d nd R ct, determined from EIS evlution k d =1/C d R d 70 Rd; Rct / Ohm Rection rte constnte / s Current density / Acm -2

40 Chrt EIA, Borovetz 2014, Norert Wgner Influence of compcting pressure: Evlution of EIS mesured during OCR, 100 ma, 80 C, 10 N NOH Z' / Z / phse / o ma ma Z'' / m m ma ma m m K 3K 10K frequency / Hz Smple R ct R por R el 48 (High pressure) m 524m 49 (Low pressure) m 577m

41 Chrt EIA, Borovetz 2014, Norert Wgner Overview EIS mesurement points nd CV with 1 mv/s t RT, 1 N LiOH, Ag-GDE 0,15 Current density / A cm -2 0,1 0,05 0-0,05-0,1-0,15-0,2 EIS mesurement point Electrode 1 (high pressure) 25c Electrode 1 (high pressure) 50c Electrode 2 (high pressure) 25c Electrode 2 (low pressure) 50c -0,25-0,3 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2 Potentil vs. RHE / V

42 Chrt EIA, Borovetz 2014, Norert Wgner Impednce mesurements during Oxygen evolution on Ag-GDE (high pressure), 1 N LiOH, 25 C Z / c d c d OCV+500 mv OCV+700 mv OCV+300 mv c d c d cd d d c d d d c d d OCV+100 mv c d c d c d c d c d c d c d c d d c c d c d d d d c d d d d c c c d d d d d d c ddddddddd d d c c d c c d c d d c d c c c d c c c c c c c d c c ccc c c c c c c c c c c c c c d d cd cd cd c d c d d d c d c c c c c c c c c c c c c c c c c c c c c c c c c c c ddd d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d K frequency / Hz phse / o Z'' / ccc dddd OCV+500 mv c c c c c c ddd d ddd d OCV+100 mv OCV+700 mv Z' / OCV+300 mv

43 Chrt EIA, Borovetz 2014, Norert Wgner Equivlent circuit used for evlution of EIS during OCR nd OER t different electrodes for Lithium-Air tteries

44 Chrt EIA, Borovetz 2014, Norert Wgner Potentil dependency of totl resistnce during ORR t different electrodes, 1 N LiOH 100 Resistnce / Ω 10 R totl ORR Electrode 1 (high pressure) 25c Electrode 1 (high pressure) 50c Electrode 2 (low pressure) 25c Electrode 2 (low pressure) 50c Potentil OCV minus x / mv

45 Chrt EIA, Borovetz 2014, Norert Wgner Potentil dependency of chrge trnsfer resistnce during OER 100 Resistnce / Ω ,1 R 2 OER (chrge trnsfer) Electrode 1 (high pressure) 25c Electrode 1 (high pressure) 50c Electrode 2 (high pressure) 25c Electrode 2 (low pressure) 50c 0, Potentil OCV plus x / mv

46 Chrt EIA, Borovetz 2014, Norert Wgner Potentil dependency of chrge trnsfer resistnce in oxide lyer potentil region (OER) 4 Resistnce / Ω 3,5 3 2,5 2 1,5 1 0,5 R 5 OER (oxide lyer) Electrode 1 (high pressure) 25c Electrode 1 (high pressure) 50c Electrode 2 (high pressure) 25c Electrode 2 (low pressure) 50c Potentil OCV plus x / mv

47 Chrt EIA, Borovetz 2014, Norert Wgner CV of polished Ag electrode, 25% KOH, O 2 st.

48 Folie 48 Bi-functionl Oxygen-Electrodes: IrO 2 /- nd Co 3 O 4 /Agelectrodes mx. overpotentil 1.5V CV s electrodes 20 wt. % ctlyst (IrO 2, Co 3 O 4 Improved cycling performnce due to use of IrO 2 nd Co 3 O 4 compred to pure Ag Current 2.6V vs. Li/Li + [ma cm -2 ] IrO 2 /Ag 99,7 Co 3 O 4 /Ag 107 Current density [ma cm -2 ] Co 3 O 4 /Ag IrO 2 /Ag Ag No IR corr. 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2.6V vs. Li/Li + Voltge vs. RHE [V] N. Wgner et l., Germn Ptent Appliction, 2014

49 Chrt EIA, Borovetz 2014, Norert Wgner Conclusion From the ctlyst screening, new ifunctionll ctlysts system for the cthode of Li-ir ttery ws found From the evlution of the mesured impednce spectr one cn propose rection mechnism for the ORR: Adsorptions- / heterogeneous rections nd chrge trnsfer rection re consecutive rections Rection mechnism nd rte determining step is chnging t higher current densities t c. 20 macm -2 Production prmeters, composition nd structure hve strong influence on electrode rectivity Chnge of rection zone with current density Silver electrodes re not stle during OER

50 Chrt EIA, Borovetz 2014, Norert Wgner Thnk you for your Attention! Acknowledgment

51 Chrt EIA, Borovetz 2014, Norert Wgner Rections pthwys for the cthodic oxygen reduction in lkline solution Direct-X 4e - -pth: 2H 2 O + O 2 + 4e - 4OH - O 2 + 2M 2M O 2 (M O + e - MO - ) 2 (MO - + H 2 O MOH + OH - ) 2 (MOH + e - OH - + M) Peroxid - Pth: H 2 O + O 2 + 2e - HO 2- + OH - O 2 + M M O 2 M O 2 + e - MO 2 - MO 2- + H 2 O MHO 2 + OH - MHO 2 + e - HO 2- + M Peroxid-Reduction: HO 2- + H 2 O + 2e - 3OH - HO 2- + M MHO 2 - MHO 2- + H 2 O MH 2 O 2 + OH - MH 2 O 2 + e - MOH + OH - MOH + e - M + OH - Ctlyticlly Peroxid-decomposition: 2HO 2- O 2 + 2OH - HO 2- + M MHO 2 - MHO 2- MO + OH - MO + HO 2- O 2 + OH - + M

52 Chrt EIA, Borovetz 2014, Norert Wgner SEM pictures of Ag-GDE, produced y the RMR technique (Ag 2 O+PTFE) Ag-GDE, unused prt Ag-GDE, used