On the Dynamic Frontier of Dr. Ran Elazari R&D of novel power sources Ariel Rosenman Prof. Gregory Salitra Doron Aurbach Daniel Sharon Bar Ilan university, Israel Prof. Boris Mrkovsky In collaboration with Prof. Elena Markevich BASF,GM,Pellion And many others..
Full EV can drive only 160 km between charges. Nevertheless, it is now a business!!! Li ion batteries take the lead! Main xEV`s Makers 2013 BEV HEV PHEV Audi Acura/Honda Audi BMW Audi BMW BYD Azure GM GM BMW BYD Chrysler Daimler/Merc GM Dodge edes Daimler/Mercede Fisker Fiat s Ford Ford Eaton Honda Honda Hyundai Fiat Hyundai Kia Ford Jaguar Mazda Honda Land Rover Mitsubishi Nissan Hyundai Lotus Porsche Jaguar Daimler/Merced Proterra Kia es Saab Land Rover Mindset Tesla Toyota Mitsubishi Mitsubishi Volvo Porsche Nissan Volkswagen Porsche Suzuki Wheego Subaru Toyota Toyota VIA Motors Volvo Volvo Volkswagen Volkswagen 2
Most Rechargeable Li + ion Batteries in Use Today Click to edit Master title style Anode Cathode Surface films Surface films Cathodes Anode Li X CoO 2 Li X C 6 LiFeO 4 Li[MnNiCO 2 Electrolyte solution: Ethylene-Carbonate & Di-Methyl Carbonate/ LiPF 6 Voltage: 3.7 V, Average Energy Density: 150 Wh/Kg D. Aurbach et Al., Materials Today, 2014
Advanced Li ion batteries : the challenge of new anodes Si anodes (Li 4.2 Si > 3500 mAh/g), but need unique morphology Click to edit Master title style A B Monolithic EC-DMC/LiPF 6 electrodes comprising Si nano-wires Monolithic Si electrodes Pristine 1 µm by sputtering 10 µm 10 µm EC-DMC-FEC/LiPF 6 D C Cycled in: DMC-FEC/LiPF 6 1 µm 1 µm 10 µm 10 µm Surface films formed in FEC-containing solutions were much thinner and compact D.Aurbach et Al., Langmuir, 28, 6175 (2012)
Galvanostatic cycling of monolithic Si electrodes Click to edit Master title style in DMC:FEC 4:1 1M LiPF 6 (“magic”) solution at 30 o C Electrodes based on Si NW 3000 3000 Current 0.132 mA (C/5 rate) Current 0.258 mA (C/2.5 rate) Capacity [mAh/g] 2500 2500 Capacity [mAh/g] 2000 2000 Charge Charge 1500 1500 Discharge Discharge 1000 1000 500 500 0 0 0 20 40 60 80 100 120 140 0 10 20 30 40 50 60 70 Cycle no. Cycle no. Electrodes based on Si sputtered on Cu
High voltage cathodes: LiNi 0.5 Mn 1.5 O 4 /Si cells (Monolithic Si electrodes prepared by sputtering) C/8 C/2 FEC-based electrolyte FEC-based electrolyte C/2 Markevich, Salitra & Aurbach, Electrochem. Comm., 2013 6
Cathodes, the limiting factor Click to edit Master title style The LiMPO 4 olivine Family Olivine Voltage theoretical Energy Range (V) Density (mAh/ g) LiFePO 4 3.4 170 (165 practical) 170 (150 practical) LiMnPO 4 4.2 4.2 170 (160 practical) LiMn 0.8 Fe 0.2 PO 4 LiCoPO 4 4.8 170 (130-140 practical) 6 5 LiCoPO 4 LiMnPO 4 4 Voltage, V LiMn 0.8 Fe 0.2 PO 4 3 LiFePO 4 For LiFePO 4, LiMnPO 4 , LiMn 0.8 Fe 0.2 PO 4 : 2 • Low cost, reasonable capacity • Good safety:low toxicity, high thermal stability • High rate capability 1 For LiCoPO 4 • High voltage, lower capacity, stability??? 0 0 50 100 150 200 Capacity, mAh/g
Li & Mn rich Li 1+x [Mn y Ni z Co w ]O 2 high capacity cathodes Click to edit Master title style R3M rhombohedral LiMO 2 : C2/m monoclinic phase: Li 2 MnO 3 = Molecularly integrated M=transition metal ion) Li[Li 1/3 Mn 2/3 ]O 2 material M Unique morphology of the BASF cathode materials It appears that XRD is less sensitive than HRTEM in studies of the phase transitions and cation ordering in the integrated layered material.
HC-MNC activated at 4.8 V in 1st cycle, further Click to edit Master title style cycled up to cut-off potential 4.6 V
Typical voltage profiles at various currents applied C-rate of the xLi 2 MnO 3 . (1-x)Li[MnNiCo]O 2 electrodes Click to edit Master title style AlF 3 -Coated Uncoated 5.0 5.0 1-st Cycle Cycle-1 4.5 4.5 4.0 4.0 Voltage / V Voltage / V ICL = 5.1 % ICL = 23.2 % 3.5 3.5 3.0 3.0 2.5 2.5 C/14 2C 2.0 2.0 C/14C/20 1C 1C C/7 C/20 2C C/7 0 100 200 300 400 0 100 200 300 400 -1 Discharge capacity / mAhg -1 Discharge capacity / mAhg The Irreversible capacity loss of the AlF 3 coated electrode is less due to lesser oxidation reactions at high anodic potentials Significant increase of the discharge capacity of the AlF 3 coated electrodes is due to higher Li storage capability of these electrodes. Aurbach , Garsuch, Lampert, Schulz-Dobrick et Al ., J. Electrochem. Soc., 160, A2220 (2013)
Advantages of Li-S and Li-O 2 over Li-ion systems • Higher Theoretical capacity, energy and power density. • Low cost (1$ per 100g) and abundant raw materials (350 ppm). • Operability at low temperature (-40 ˚C). 11 Bruce, P. G., Freunberger, S. A., Hardwick, L. J., Tarascon, J.-M.. Nature materials 11 , 19 – 29 (2012).
Working Mechanism Formation and re-oxidizing Li 2 S n Sulfur-cathode LiNO 3 Li-anode Discharge Li-Polysulfudes S 8 Shuttle Li 2 S 8 effect diffuse to the anode Li 2 S 6 Insoluble products + Li 2 S 4 + Li 2 S 2 Li 2 S Charge 12 12 Bar Ilan University 12
Rechargeable lithiated silicon-sulfur (SLS) cells vs. Li-S reference cells, an important new direction Li – Sulfur Cells (reference) Sulfur/Lithiated a-Si Li-Ion Cells 13
Activated carbon cloth impregnated with sulfur as possible cathodes for Li-S system. Electrode Preparation S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S 8 S S S S S S S S S S S S S S S S S S S 8 S S 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 a a b b 14
Electrochemical performance of S/kynol 2000 Discharge potential is limited to 1.9V Charge/Discharge capacity vs. Charge/Discharge profiles vs. cycle number voltage 0.65 mA/cm2 1.3 mA/cm2 • ~3.12 mg/cm 2 of sulfur impregnated on activated Binder Free. carbon cloth disc (kynol 2000 m 2 /g, 14 mm φ ) under Rigid Structure. vacuum in a sealed glass ampulla at 200 ° C for 10h. High Porosity & • Cell where cycled at current density of ~1 mA/cm 2 Surface Area. (~C/5) unless indicated otherwise between the voltage range of 2.5V and 1.9V. 15
Li-L 2 S cells: towards Li ion sulfur systems a) b) Proposed mechanism for redox mediated Li 2 S oxidation Ox. Li 2 S Li 2 S Li 2 S Red. The best red-ox mediator we found so far: Decamethylferrocene Fe(η 5 -C 5 Me 5 ) 2 Pristine Electrode No Additive With Redox Couple
Using monolithic high surface area activated carbon cloth electrodes Decoration by α -MnO 2 nano-particles can reduce the oxidation potential via electro-catalysis The most relevant electrolyte solution: CH 3 O(CH 2 CH 2 O) n CH 3 / LiTFSI LiN(SO 2 CF 3 ) 2 4.3 V ACM ACM α -MnO 2 The over-potential dropped to in more then 0.5 V by introducing MnO 2 catalyst D. Aurbach et Al.,J. Mater. Chem. A, 1, 5021(2013)
Proposed degradation mechanism of polyether solvents during oxygen reduction (in the presence of Li ions) Li O O Li b a H 3 CCO 2 Li a :B CH 3 OCH 2 CH 2 OCH 2 CH 3 O Li 6b H 1 Li 2 O 2 HB b CH 3 CHO d O d 5 6a OCH 2 CH 2 OCH 2 Li CH 3 OO + c 3 2 c OCH 2 CH 2 O Li Li Li 4 O O Li O Li 2 O 2 Li 2 O 2 HCO 2 Li LiOCO 2 Li CO 2 + LiOLi H 2 C 7 10 The lithium cation is a hard electrophile which is expected to bond strongly to the hard Lewis base oxygen anions. This in turn helps to convert the alkoxy groups into better leaving groups and facilitates nucleophilic attacks by Li 2 O 2 .
Are rechargeable Li-O 2 batteries realistic? 1. Carbonates ORR- reactivity with the oxides 2. Polyether ? Electrolyte solution 3. DMSO 4. DMF ??? stability OER- low solution oxidation potential Enhances electrolyte solution degradation Carbon stability Carbon replacement? Reacts with O 2 , super-oxides & peroxides Enhances solution degradation and oxidation Catalyst integration Introducing more contaminations
Still not found The “perfect” system 5 nm O 2 O 2 O 2 GAS
Carbonates solvents Non functional system O 2 O 2 GAS
Polyethers, DMSO, Sulfolane, DMF, Etc... Complex system 500 nm + O 2 O 2 GAS
More studies should be done Complex system with inert Negligible cathode 5 nm + Inert cathode O 2 O 2 GAS
The effect of the lithium oxides source Chemical reactions of oxides may be very different from those observed under electrochemical reactions that involve primarily electron transfer processes. In fact, the main side reactions should occur during the formation of the reduced oxygen species in the anionic form (catalyzed by Li ions in solutions, before precipitation as solid Li 2 O 2 deposits. Substrates: organic Moieties / Solvent molecules
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