| 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: 507/Battery/Regular (Oral) SCHEDULED: 14:00/Tue. 29 Nov. 2022/Similan 2 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. |
