AMELIE : Advanced Fluorinated Materials for High Safety, Energy and Calendar Life Li Ion Batteries

Transcription

1 AMELIE : Advanced Fluorinated Materials for High Safety, Energy and Calendar Life Li Ion Batteries Join EC / European Green Car Initiative Workshop 2013 Electric Vehicle Batteries: Moving from Research Towards Innovation 10 April 2013 Jean-Yves Sanchez

2 Project full title: Project general information Scientific coordinator : Coordinator : Starting Date: 01 Jan 2011 Ending Date: 01 Jan 2014 Advanced Fluorinated Materials for High Safety, Energy and Calendar Life Li Ion Batteries. Jean-Yves.Sanchez@lepmi.grenoble-inp.fr Thierry.Baert@Solvay.com Budget Total/Funding: Partners: 5,2 MEUR / 3,5 MEUR

3 Motivation and objectives. To increase EV/PHEV autonomy while improving the safety of the battery and focusing on the recycling of some higher value materials. Focus on 5V Li-ion batteries based on high specific energy cell consisting of a high voltage positive i.e. LiNi 0.4 Mn 1.6 O 4, associated to lithiated graphite; both electrodes using improved fluorinated binders. To operate these challenging cells, AMELIE aims at developing new stable liquid electrolytes, discarding the unsafe LiPF 6, and including fluorinated solvents and additives to decrease the fading and the self-discharge. To increase the battery performance, new macroporous separators will be investigated, in order (1) to decrease the ohmic drop in the set electrolyte + separator (2) to improve the electrolyte/electrodes interfaces and (3 ) to improve the safety of the cell.

4 2011 Key progresses Selection & supply of LNMO LiNi 0.4 Mn 1.6 O 4 New PVdF based binders good cohesion & adhesion to Cu, Al current collectors Cathode & anode formulation Additive selection & content optimization S.A 1- F E.C

5 2012 Key progresses Benchmarking: LNMO benchmarking versus NMC Full cell compared to NMC based commercial batteries Lithium salts: Design and synthesis of 5 dissymmetric sulfonimide lithium salts Nanocomposite membranes based on NanoCrystallineCellulose NCC Reinforced macroporous separators: based on PVdF homopolymer Porosity to be filled by liquid electrolytes Reinforced dense membranes: Based on VdF copolymers Liquid electrolyte uptake Gelled Polymer Electrolytes

6 Main technical activities - on Electrodes Lithium-ion battery components + LMNO 4.95 V has reached the scale-up phase. Selecting HMW PVDF allowed lowering the binder content down to 5%. - has been formulated using 89% of SLA Superior Graphite, 3% CB and with different type of PVDF binders. The most adapted formulation has been selected. The slurry properties have been studied as well, to optimize the coating production process.

7 Main technical activities - on Electrolyte/Separators Lithium-ion battery components The interactions Electrolyte / new PVDF Separator have been tested in different configurations. A nanocomposite approach based on NCC NanoCrystallineCellulose was successfully tested with both porous & dense separators. Major improvements of the mechanical properties have been obtained and give access to thinner membranes with a much lower impact on conductivities than Celgard LEPMI is now able to supply partners in thin NCC-PVdF macroporous separators (10 to 15 µm thick). However the scale-up of the production of these separators seems impossible in the time allotted to AMELIE.

8 Electrolyte/Separators. Why NCC? Nano Crystalline Cellulose - Bio sourced - High mechanical strength - Low toxicity (LC50 = 2g/L) - High electrochemical stability - Low Cost Average Length 109 ± 49 nm Average Diameter 6.60 ± 1.2 nm L/D 16.6 Percolation Threshold (V Rc ) 4.2% E (DMA) 4.5 RT TEM

9 Electrolyte/Separators. NCC-PVdF Macroporous Separators X 3 X 10 composite Solef % whiskers Solef composite Solef % whiskers Storage modulus (MPa) 10 composite Solef % whiskers composite Solef % whiskers composite Solef % whiskers T ( C)

10 E' (Pa) Electrolyte/Separators. Dense NCC-PVdF separators & modeling DMA of dense PVdF-HFP + NCC PVdF-HFP + 30% NCC PVdF-HFP + 12% NCC PVdF-HFP 0% NCC X 10 3!! T ( C) E. c E r 0 for V R V Rc VR V 1 V Rc Rc b for V R V V R = volume fraction of NCC E S = tensile modulus of matrix E R = tensile modulus of charge Rc Porous membranes modeling: Y E th (Mpa) E 150 C (Mpa) R R S Mechanical behavior follows the percolation model for the dense membranes, while it needs further adaptation for the porous ones.

11 Weight loss (%) NCC reinforced separators: thermal stability TGA of PVdF and PVdF-HFP porous and dense membranes -Weight loss starts ~ at 260 C - Safety asset Recovery of the expected wt% of NCC in MP separators P.Inv retains NCC PVdF (porous) PVdF + 6%NCC (porous) PVdF + 12% NCC (porous) PVdF-HFP (dense) PVdF-HFP + 6%NCC (dense) PVdF-HFP + 12%NCC (dense) NCC based separators: - Extended Patent: Japan, USA etc. from INP Grenoble - Scale-up of NCC-separators: To be done. Temperature ( C)

12 Electrolyte/Separator : benefits & bottlenecks Li-salts: salts much safer than current LiPF 6 have been supplied by SME ERAS: Extended patent: INP Grenoble & ERAS. 3 of them have sufficient conductivities and dissolve in a variety of solvents Their electrochemical stability window adapted to a variety of Li-ion batteries But their stability vs LNMO is questionable non-tested in Full cells Deserve to be tested in other batteries in a future project F-solvents: They have been supplied by Solvay and, for 2 of them, by ERAS Solvents supplied by ERAS are easy to manufacture but are instable vs LMNO Deserve to be implemented with other positives in a future project Several F-solvents supplied by Solvay could be used with LNMO Al corrosion: induced by Electrolytes based on Lithium salts much safer than LiPF 6 : AMELIE allowed to solve the Al corrosion European Patent (shared by INP and WWUM) is in progress

13 Main technical activities: half and full cells Half cell tests allowed optimizing the battery components Full cells have been tested, with the new formulation of LNMO, and of graphite. Electrolyte LF30 based on LFAP salt at 30 C: voids (charge) full (discharge) Without additives Triangle With S.A & 1FEC squares Separator Celgard 2400, 24 µm thick. C.Arbizzani, F.De Giorgio, L.Porcarelli, M.Mastragostino, V.Khomenko, V.Barsukov, D.Bresser, S.Passerini, J.Power Sources, doi: /j.jpowsour Additives allowed: - improving recovered charge - improving capacity retention - decreasing self-discharge

14 Conclusions Main achievement obtained on coin cells at Lab level. High voltage active materials giving access to 200 Wh/kg. Electrolyte improvement based on additives. Nanocomposite Separators -Outstanding performances : produced at Lab scale. Upscaling? Main achievement dealing with Al corrosion: WWUM & G-INP overcame the issue dealing with Al corrosion: Usable with a variety of safe salts Usable with a variety of Li-ion batteries (European patent pending) Next steps. Scale up and optimization of formulations (reliability). New selected salts and solvents for electrolyte under testing: Mixture of liquid electrolytes & Ionomers Improve reliability of production of Nanocomposite Separator at low thickness and the functionalization of the Fluorinated polymers