ORALS

SESSION: BatteryMonPM3-R9	Yazami International Symposium (7th Intl. Symp. on Sustainable Secondary Battery Manufacturing & Recycling)
Mon. 28 Nov. 2022 / Room: Similan 2
Session Chairs: Hee-Dae Lim; Sebastien Martinet; Session Monitor: TBA

17:50: [BatteryMonPM313] OL Invited
Phase Transitions of Hybrid Organic-Inorganic Perovskites
Wei Li¹ ; ¹Nankai University, Tianjin, China;
Paper Id: 485 [Abstract]

Hybrid organic-inorganic perovskites have attracted significant attention in the past two decades owing to their enormous application potential in energy. Like their oxide counterparts, these hybrid organic-inorganic systems exhibit abundant phase transitions which can often lead to significant changes in the electrical, magnetic, and optical properties that are of vital importance for the design and fabrication of functional devices. However, the atomistic driving forces and underlying mechanism need to be well understood for these hybrid perovskite systems. In this talk, I shall present our recent advances in the thermally and pressure-driven phase transitions and their microscopic mechanisms of some three-dimensional and two-dimensional hybrid organic-inorganic perovskites. At the same time, I shall discuss the symmetry alternation at the interface and corresponding atomic origin of some two-dimensional hybrid organic-inorganic perovskites.

References:
1. K. Li, Z.-G. Li, J. Xu, Y. Qin, W. Li*, A. Stroppa, K. T. Butler*, C. J. Howard, M. T. Dove, A. K. Cheetham, X.-H. Bu*, "Origin of ferroelectricity in two prototypical hybrid organic–inorganic perovskites", J. Am. Chem. Soc., 2022, 144, 816.
2. W.-J. Wei, X.-X. Jiang, L.-Y. Dong, W.-W. Liu, X.-B. Han, Y. Qin, K. Li, W. Li*, Z.-S. Lin*, X.-H. Bu*, P. Lu*, "Regulating second-harmonic generation by van der Waals interactions in two-dimensional lead halide perovskite nanosheets", J. Am. Chem. Soc., 2019, 141, 9134.
3. W. Li*, L. Ji, "Perovskite ferroelectrics go metal-free", Science, 2018, 361, 132.
4. W. Wei, W. Li*, K. Butler*, G. Feng, C. J. Howard, M. Carpenter*, P. Lu*, A. Walsh, A. K. Cheetham, “Unusual phase transition driven by vibrational entropy changes in a hybrid organic–inorganic perovskite”, Angew. Chem. Int. Ed., 2018, 57, 8932.
5. W. Li*, Z.-M. Wang, F. Deschler, S. Gao*. R. H. Friend*, A. K. Cheetham*, "Structural diversity and multi-functionality of hybrid organic-inorganic perovskites", Nat. Rev. Mater., 2017, 2, 16099.

SESSION: BatteryTuePM1-R9	Yazami International Symposium (7th Intl. Symp. on Sustainable Secondary Battery Manufacturing & Recycling)
Tue. 29 Nov. 2022 / Room: Similan 2
Session Chairs: Alain Tressaud; Xuejie Huang; Session Monitor: TBA

14:00: [BatteryTuePM105] OS
NANO-FLUORIDE MATERIALS AS ACTIVE COMPONENTS IN PRIMARY AND SECONDARY LI-BATTERIES
Alain Tressaud¹ ; Henri Groult² ; Etienne Durand³ ; Wei Li⁴ ; Damien Dambournet⁵ ; ¹ICMCB-CNRS, University Bordeaux, Pessac, France; ²Sorbonne University, Paris, France; ³ICMCB-CNRS, PESSAC, France; ⁴Nankai University, Tianjin, China; ⁵Sorbonne Uuniversity, Paris, France;
Paper Id: 507 [Abstract]

Energy storage is one of the most important challenges for the 21st century. The improvement of the electrochemical performances implies the development of new class of electrode materials, allowing higher energy density, longer cycle life, moderate cost, etc. In this context, nano-fluoride materials may occupy a noticeable place in both primary and secondary batteries. 1) Nano-CFx in primary Li batteries - The electrochemical performances of primary Li-battery, can be improved by developing new materials with higher potential and energy density values [1-4]. New kinds of carbon-fluorine nanoparticles are suitable since they allow combining the physical properties of CFx with the effect of nanosized particles. These materials allow having higher OCV and suppressing the potential delay, generally observed during the first time of the discharge reaction in commercial graphite fluorides. 2) CoF3-based materials in secondary Li batteries In reversible Li batteries, several types of transition metal trifluorides and derived (MX3, with M=Ti, Mn, Fe, Co) have been tested for increasing the electrochemical performances because these compounds may incorporate three electrons per 3d-metal during the process, thus delivering higher energy density, and exhibiting longer cycle life Nano-CoF3 have been synthesized by direct fluorination (with F2-gas) of cobalt nanoparticles at various temperatures (up to 300°C). When handled in very dry atmospheres, CoF3-based samples are stable vs. traces of humidity and can be used to prepare electrodes in fairly good conditions for batteries. The best electrochemical performances were obtained with nano-CoF3 powders prepared at TF2 = 100 °C, for which a reversible capacity of about 390 mAh/g was obtained after subsequent cycles [5]. More recently, high-energy X-ray data, showed that in fact CoF3 decomposes during the discharge process into an intermediate compound with a new structure/composition [6]. Using the pair distribution function, the structure was elucidated to correspond to a defect corundum phase exhibiting Co vacancies, i.e., Co1.26IICo0.16III0.58F3.

References:
1) A.Tressaud, in Fluorine-carbon and fluoride-carbon materials, Chap. 2, M. Dekker, NY, 1995, 32.
2) C. Delabarre, M. Dubois , J. Giraudet, K. Guerin, R. Yazami, A. Hamwi, Electrochemical society transactions, 36, (2007),153-163.
3) K. Le Van, H. Groult, F. Lantelme, M. Dubois, D. Avignant, A. Tressaud, S. Komaba, N. Kumagai, S. Sigrist, Electrochim. Acta, 54, (2009), 4566-4573.
4) A. Tressaud, H. Groult, J. Fluor. Chem. 219, (2019 ), p.1-9,
5) H. Groult, S. Neveu , S. Leclerc , A.-G. Porras-Gutierrez , C.M. Julien, A. Tressaud, E. Durand, N. Penin, C. Labrugere, J. Fluor. Chem. vol. 196, (2017), p. 117-127.
6) W. Li, H. Groult, O. J. Borkiewicz, D. Dambournet, J. Fluor. Chem. 205 (2018) pp.43-48.