ORALS

SESSION: MoltenThuPM1-R1	Angell International Symposium on Molten Salt, Ionic & Glass-forming Liquids: Processing and Sustainability (7th Intl. Symp. on Molten Salt, Ionic & Glass-forming Liquids: Processing and Sustainability).
Thu Oct, 24 2019 / Room: Ambrosia A (77/RF)
Session Chairs: Alois Loidl; Michel Armand; Session Monitor: TBA

14:25: [MoltenThuPM106] Plenary
Polymer Electrolytes, in Search for the Elusive Decoupling
Michel Armand¹ ; ¹CIC Energigune, Paris, France;
Paper Id: 73 [Abstract]

Polymer electrolytes have been an active field of research since the late 70's. This has culminated in the commercial launching of lithium metal polymer electrolytes batteries powering a fleet of cars since 2011 in different cities in France ^[1]. The poly(ethylene oxide) - PEO-based as 'solvent' for a low lattice energy salt has been the key to obtain decent conductivities. The operational temperature, however, is a ≈ 70°C, i.e. 10°C above the melting point of crystalline PEO and 100°C above the T_g of the resulting melt. These systems are coupled (diffusion with segmental motion) and can be called "fragile" according to Angell definition ^[2]. Besides, the fraction of the current carried by the cations (Li⁺, Na⁺), the only important species in the electrodes processes, expressed as T+, is only 0.2 to 0.3. <br />We will discuss here the strategies to improve the performances of such ionic conductors in the hopes to meet the requirement for the dearly sought after high energy density battery operating at/close to room temperature, and safer and longer cycling than the present ones using flammable liquid electrolytes technology. <br />Without resorting to modify PEO, the modification of the solute (salt) is one fruitful strategy. The introduction of the extensively delocalized fluorinated imides (R_fSO₂)₂N^- (R_f = F, CF₃) anions where the charge is spread on 5 centers and importantly possess a a"hinge", with the flexible S-N-S "pia" bonds lowering the T_g of the resulting solid solution with PEO, have revolutionized the field. This is also true for ionic liquids, in majority based on these anions.<br />The concept can be pushed further with the "super imide" family, where the charge is further delocalized and the number of "hinges" extended. The first example is [(CF₃SO₂N)₂S(O)(CF₃)] with two S-N-S "pi" bonds. The T_g for the polymer-salt complex is thus further lowered (Fox equation). Besides, when this salt is tethered to a polymer to immobilize the anion, this results in the highest conductivities reported for a single-ion conductor (T₊ = 1) ^[3]. <br />Manipulation of the simple anions, while still keeping the flexible imide linkage, allows the increase of T+ to ≈ 0.5 by simply removing one fluorine from (CF₃SO₂)₂N to (CF₂HSO₂)(CF₃SO₂)N , resulting in H bond formation with the ether oxygens, slowing the negative charge correspondingly ^[4]. Alternatively, the (CF₃SO₂)N( )SO₂- moiety can be kept, attached to either long alkyl chains or short EO units. The former anions result in nanophase separation with the formation of micelles; for the latter, the CH₂CH₂O units attached to the imide center plasticize the polymeric chains without participating in the solvation. Both systems results in much decreased anion mobility, keeping the Li⁺ diffusion at a high value. Both salts seem to, for the first time, exhibit some decoupling. <br />The salt aspect as well as that of new alternatives to PEO will be discussed.

References:
[1] http://www.bollore.com/en-us/activities/electricity-storage-and-solutions/electric-vehicles-solutions.\n[2] Angell, C. A. (1995). "Formation of Glasses from Liquids and Biopolymers". Science. 267: 1924 -1935.\n[3] Ma et al. https://doi.org/10.1002/anie.201509299\n[4] Zhang et al., DOI: 10.1002/anie.201813700

SESSION: ChemistryFriPM2-R9	Tressaud International Symposium on Solid State Chemistry for Applications and Sustainable Development
Fri Oct, 25 2019 / Room: Aphrodite A (100/Gr. F)
Session Chairs: Jean-Luc ADAM; Thierry Loiseau; Session Monitor: TBA

16:45: [ChemistryFriPM211] Plenary
From Solid State Chemistry to Solid State Electrochemistry: Lithium Metal Polymer Batteries
Christian Julien¹ ; Karim Zaghib² ; Michel Armand³ ; John Goodenough⁴ ; Alain Mauger¹ ; ¹Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France; ²Hydro-Quebec's Center of excellence in transportation electrification and Energy Storage, Varennes, Canada; ³CIC Energigune, Paris, France; ⁴Texas Materials Institute, Austin, United States;
Paper Id: 405 [Abstract]

HQ-CNRS started work on lithium metal with polymer electrolyte in lithium rechargeable batteries in 1979. Since that time, battery research has expanded worldwide. Several new polymers, solid electrolytes and ionic liquids with improved conductivity have resulted from a better understanding of the major parameters controlling ion migration, such as favorable polymer structure, phase diagram between solvating polymer and lithium salt, and the development of new lithium counter-anions. In spite of the progress so far, the quest for a highly conductive dry polymer at room temperature is still continuing and all-lithium polymer battery (LPB) developers presently face the challenge of whether to heat the PEO-based polymer electrolyte to enable high-power performance, as required for electric vehicle and energy storage or develop a polymer electrolytes conductive at RT. LPB developers have explored both the high-temperature and low-temperature options. This presentation provides an overview and progress in developing three battery technologies: 1. Lithium-metal-based batteries made from dry polymer and ionic liquid-polymer electrolytes for rechargeable lithium batteries with olivine (LFP and LMFP). 2. All solid-state batteries using Li°-NMC. 3. High voltage composite polymer- ceramic for all solid state batteries. We compare the performances the energy density, the cost, and safety of li-ion batteries vs. solid state batteries. In this presentation we will explain the process from materials to the system (cell, module and pack).