Electrolytes for Innovative Li-Batteries

Size: px

Start display at page:

Download "Electrolytes for Innovative Li-Batteries"

Daniela Wells
5 years ago
Views:

1 Miriam Kunze, Alexandra Lex-Balducci Andrea Balducci, Stefano Passerini, Gerhard Hörpel, Martin Winter Neue Materialien in der Energietechnologie: Batterietag NRW Dr. Miriam Kunze

2 uture market of the Li-Ion Battery 2 no replacement for Li-Ion Batteries in the near future Takeshita, H., 25 th Int. Batt. Symp. & Exhibit

3 Temperature Range 3 present LIB technology Space industry

4 Li-Ion Battery Technology 4 Graphite Lithium salts in organic solvents Metal oxide Lithium-Ion Anion Separator Anode Electrolyte Cathode

5 uture Goals with Ionic Liquids 5 Li-Ion Batteries achieved many goals but: increase of temperature range safety problems like overcharge and overheating has to be resolved replacement of volatile and flammable electrolyte compounds

6 What are Ionic Liquids? 6 salts with a melting point below 100 C mainly consists of an inorganic anion and a irregular organic cation wide liquid range (up to 250 C) thermal and chemical stability non-flammable negligible vapor pressure non-volatility C H 3 N + Pyr(14)SI CH3 S N - S

7 What are Ionic Liquids? 7 salts with a melting point below 100 C mainly consists of an irregular inorganic anion and a organic cation wide liquid range (up to 250 C) thermal and chemical stability non-flammable negligible vapor pressure non-volatility wide electrochemical stability window ( > 5V) conductivity at room temperature green electrolyte ESW: > 5.0 V Zhou et al., J. Phys. Chem B, 2008, 43; 3577

8 Ionic Liquids inthe Winter Group 8 N + H 3 C CH 3 S N + N - S H 3 C CH 3 N - S S PYR(14) SI T M = -18 C PYR(13) TSI T M = 11 C Melting point T M : 1)DSC heating traces 2)changes of the NMR peak width at half maximum Mobilities of the ions at different temperatures: 1)conductivity 2)diffusion coefficients (Pulsed ield Gradient-NMR) Electrochemical properties

9 Tailored Ionic Liquids 9 N + H 3 C CH 3 PYR(14) SI T M = -18 C T d : 175 C S N - S ESW: > 5.0 V σ RT : > 3 ms/cm σ 15 C : 1 ms/cm Zhou et al., J. Phys. Zhou Chem et al., B 43 J. Phys. (2008) Chem B, 2008, 43; 3577

10 Melting of the Ionic Liquids 10 D(anion) D(cation) Pyr 14 SI Pyr 13 SI

11 Melting of the Ionic Liquids 11 Pyr 14 SI Pyr 13 SI D(anion) D(cation) melting behavior strongly influenced by the size and structure of the cation ionic conduction below T M possible

12 Ionic Liquids as electrolytes mixed with Li-salts 12 high ionic conductivity at sub-ambient temperatures wide electrochemical stability window (ESW)

13 Li 0 plating in IL-based Electrolyte 13 C-rate: Li / 0.9PYR 14 SI 0.1LiSI /Li (Ni) reversibility of the lithium plating process higher than 99.5%

14 Li-Ion Cells with IL-based Electrolyte 14 C-rate: Li / 0.9PYR 14 SI 0.1LiTSI /LP high reversibility of the intercalationdeintercalation process good cycling performance stable long-term capacity as well for full cells

electrolyte 2- The cells are placed under the same

15 Li-Ion Cells with IL-based Electrolyte 15 Vacuum test 1- Two identical vacuum sealed cells differing only for the electrolyte 2- The cells are placed under the same vacuum level RGANIC RGANIC ELECTRLYTE ELECTRLYTE INIC LIQUID

16 Conclusions 16 very promising results using Ionic Liquid-based electrolytes as well at low temperatures: long-term stability good cycling performance non-volatility BUT: these good results performed at C-rates of 1/10 for higher rates worse idea: mixing different IL s for the electrolyte

17 Münster Electrochemical Energy Technology 17 Thank You for Your attention!

Electrochemical Cells

CH302 LaBrake and Vanden Bout Electrochemical Cells Experimental Observations of Electrochemical Cells 1. Consider the voltaic cell that contains standard Co 2+ /Co and Au 3+ /Au electrodes. The following