SOLIK Li-hochleitende Keramiken für all-solid-state Batterien

Transcription

1 SOLIK Li-hochleitende Keramiken für all-solid-state Batterien Dr. Ningxin ZHANG Electric Drive Technologies Center for Low-Emission Transport Austrian Institute of Technology GmbH

2 Outline Basic Data Project vision Good reasons for project Progress Perspectives Conclusion

3 Basic data Name of Institute: Austrian Institute of Technology GmbH Name and of project leader: Ningxin ZHANG, Partners: Paris-Lordon University Salzburg, Inst. Mater. Chem. & Phys. Technical University of Vienna, Inst. Tech. Chem. Förderprogramm: e!mission.at, 4 th Call Project Number: Duration: 01 May October 2017 (extended) Project budget: 701,

4 Visions Developing garnet structured electrolytes with the highest Li + conductivity through optimized strategy on doping and synthesis (PLUS). Uncovering the relationship between Li + conductivity and materials paramters of garnet electrolytes (TUW & AIT) Assembly and characterization of prototype all-solid-state LIBs (AIT) 4

5 Good reasons / Excellence Why All-Solid-State LIB: Green emobility Safety Why garnet structured LLZO (Li 7 La 3 Zr 3 O 12 ) electrolyte Phase structure Doping strategy Know-how on preparation of prototype Size effect Integration process Yuki Kato, et al, Nature Energy, DOI: /NENERGY John Christopher Bachman, et al, Chemical Review, DOI: /acs.chemrev.5b Dong Ok Shin, et al, Scientific Reports, DOI: /srep

6 OUTLET Basic Data Project vision Excellence of project Progress: synthesis of LLZO Perspectives Conclusion

7 LLZO powders synthesis Solid state process Synthesis strategies: Solid-state process Sol-gel process Sol-gel method sol gelation gel calcination 7

8 LLZO powders synthesis: XRD Solid state process Sol-gel process 8

9 Sintering parameters Li 7 La 3 Zr 2-x Nb x O 12 Solid state process Sol-gel process For powders synthesized via sol-gel process, small grains are obtained. For powders prepared with solid-state process, an optimized sintering strategy of lower temperature with prolonged time helps to grow large crystals. 9

10 Finished compositions D 3+ xli 7-x La 3 Zr 2 O 12 Li 7-y La 3 Zr 2-y D 5+ yo 12 Al Ga Ta Nb method solid state yes yes no Yes sol-gel no no yes Yes Doping level x(y) (per formula unit) Temperature ( C) 0.15/0.20/0.3/ /0.20/0.30/ /0.50/0.7 5/1.00/1.25/1. 50/1.75/ /0.50/0.75/ 1.00/1.25/1.50/ 1.75/2.00 synthesis 850 C/1050 C/1200 C 900 C/1100 C/1200 C 10

11 OUTLET Basic Data Project vision Excellence of project Progress: measuring Li + conductivity Perspectives Conclusion

12 Electrode configuration Type Metal paste Sputtered film Metal foil Materials Ag/Pt/Au Au/Pt/Li Li Treated Temperature 200~300 o C RT RT/170 o C Electrodeeletrolyte interface 12

13 Analysis of EIS R b R b +R gb Overall R R b R gb Solid State Ioncs,177(2006) J. Power Sources, 206(2012) J.Am.Ceram.Soc.,98(2015) Sputtered Au as electrodes Li foil as electrodes Sputtered Pt as electrodes 13

14 Microelectrodes Impedance Analyzer LLZO Microelectrodes Tip (W) Counter electrode Heat or cooling Counter electrode: Electrode: Ti/Pt 10 nm Ti 200 nm Pt Ø: µm Material: Al 0.20 pfu The application of microelectrodes makes it possible to identify the influence of grain boundary. 14

15 EIS results with microelectrode Repetitivity of EIS ~8mm Influence of electrode size Selection of electrodes Coutour plot of Li + conductivity The distribution of Li + conductivity in Al doped LLZO samples 15

16 Influence of electrode type Targets: Clearify the influence of electrode/electrolyte interface on the ionic conductivity in solid electrolyte Determnation of suitable electrode Samples: 6 LLZO pellets doped with Ga 0.3 with the similar geometry Same sintering and post treatment processes Electrode configuration: Symmetric: Ag-LLZO-Ag // Au-LLZO-Au // Li-LLZO-Li Asymmetric: Ag-LLZO-Au // Ag-LLZO-Li // Au-LLZO-Li Assembled into coin cells in a glove box filled with Ar 16

17 -Im(Z) (MΩ cm) EIS results 1 0,8 Au-LLZO-Au Li-LLZO-Li Li-LLZO-Au Li-LLZO-Ag Ag-LLZO-Au 0,6 0,4 0, ,2 0,4 0,6 0,8 1 Re(Z) (MΩ cm) 23 o C J Phys Chem Lett, 2015, 6,

18 LnR -Im(Z) (Ω) C 29 C 37 C 45 C C 66 C 78 C 92 C LLZO-Nb-0.25 EC-Lab Re(Z) (Ω) 9 8 Grain Grain boundary y = 6,0029x - 12,008 R² = 0,9992 RT: Grain σ = 3,52e-4 S/cm Grain boundary σ = 6,26e-5 S/cm Linear (Grain) Linear (Grain boundary) y = 3,1019x - 3,8978 R² = 0, ,5 2,7 2,9 3,1 3,3 3,5 1/T*1000 (K-1) 18

19 Ionic conductivity S/cm Summary of doping effects 1,E-02 1,E-03 Ta doped LLZO Nb-doped LLZO 1,E-04 1,E-05 1,E ,25 0,5 0,75 1 1,25 1,5 1,75 2 Doping level (pfu) Comment: Doping effect of Al & Ga to Li is more effective than that of Nb & Ta to Zr. Daniel Rettenwander, et al, Chem Mater, 2016, 28,

20 LLZO-Ga0.3pfu A possible mechanism is the evoluton of space charge layer as a function of temperature?? Arrhenius plot of conductivity of LLZO nanofiber membrane, PNAS, doi/pnas

21 OUTLET Basic Data Project vision Excellence of project Progress: Preparation of all-solid-state LiBs I. LLZO ceramic pellet II. LLZO thick film on separator III. LLZO thick film on anode Perspectives Conclusion

22 Thin Film battery Preparation of targets Structure & sintering Thin film deposition Magnetron sputtering by Energy Department of AIT in Tech Gate broken target due to thermal mismatchingbetween Cu plate and LLZO ceramic 22

23 Current (A) LLZO ceramic pellet: half cell 3,0E-06 2,0E-06 1,0E-06 Graphite-LLZO(Al0.2)-Li Graphite LLZO pellet Li foil 0,0E+00-1,0E-06 1st CV 2nd CV -2,0E-06-3,0E Voltage (V) 23

24 Specific capacity (mah/g) Current (µa) II. Thick LLZO film: full cell Assembly C/2 C/5 EIS LNMO-LLZO thick film-graphite LNMO-LLZO thick film-graphite ,5 3 3,5 4 4,5 5 5,5 Voltage (V) 1C LNMO LLZO thick film /separator Graphite C 4C 6C 6C 1C 1C Cycle number CV curve showed lithiation & de-lithiation peaks ~30% of the specific capacity of LNMO reached 24

25 III. LLZO-anode composite film Direct coating of LLZO film on anode Co-calendaring of electrolyte-electrode composite film LLZO - anode composite film Li foil Li metal piece as counter electrode After coating Assembly into EL-CELL Electrochemical measurements ungoing 25

26 Dissemination of results Publications on peer reviewed journals: Daniel Rettenwander, et al, Structural and electrochemical consequences of Al and Ga consubstituion in Li 7 La 3 Zr 2 O 12 solid electrolytes, Chemistry of Materials, 2016,28, (2016 IF: 9.407) Reinhard Wagner, et al, Crystal structure of garnet-related Li-ion conductor Li 7-3x Ga x La 3 Zr 2 O 12 : fast Li-ion conduction caused by a different cubic modification? Chemistry of Materials, 2016,28, (2016 IF: 9.407) Andreas Wachter-Welzl, et al, Microelectrodes for local conductivity and degradation measurements on Al stabilized Li 7 La 3 Zr 2 O 12 garnets, Journal of Electroceramics, 2016, doi: /s (2016 IF:1.263) Conference paper: Ningxin, Zhang, et al, Electrode interface effect on Li ionic conductivity of garnet solid electrolyte LLZO, ABAA9, the 9 th International Conference on Advanced Lithium Ion Batteries for Automotive Applications, 17-20th October, 2016, Huzhou, China. 26

27 Summary and perspectives Summary Combination among: Crystal structure and chemistry Electrical measurement and mechanism analysis Battery building and evaluation Perspective Gap to target Possibility to reach the target 27

28 Acknowledgment Thanks for the finacial support of this project from: Thanks for the great cooperation within the project: Prof. Georg Amthauer, Prof. C.A. Geigther, Dr. Daniel Rettenwander, Dr. Reinhard Wagner, and M. M. Maier et al from PLUS. Prof. Jürgen Fleig and Dr. Andreas Wachter-Welzl, Stenfanie Taibl et al from TU Wien. Prof. Atanaska Trifonova and other colleagues from AIT. 28

29 THANK YOU! Ningxin ZHANG, 27 th March 2017