Séminaire "Energy storage beyond the horizon: materials and mechanism", Éléonore Mourad
Venue: bibliothèque de l'équipe AIME
Energy storage requires both enhancing intercalation based batteries and going beyond their limitations in terms of energy, power, sustainability and cost with potentially game‐changing approaches ‘beyond intercalation chemistries’. This is where our research is focussed with the development of new materials and the fundamental scientific understanding. Particular chemistries involve metal-O2 and intercalation chemistries with Li and Na. To understand the processes we develop (in-situ) methods. Here I will discuss recent advances with these materials and reaction mechanisms.
The redox chemistry of O2 moieties has become focus of forefront battery research such as on metal-O2 batteries and Li-rich layered oxides (1, 2). O2 evolution is in either case a critical yet not fully understood phenomenon(1, 3). Operation of the rechargeable metal-O2 batteries depends crucially on the reversible formation/decomposition of metal (su)peroxides at the cathode on discharge/charge. The greatest challenge arises from severe parasitic reactions that decompose the electrolyte and porous electrode. So far these reactions have been ascribed to the reactivity of superoxide and peroxide. Yet, their reactivity cannot consistently explain the observed irreversible processes. We have recently shown that the highly reactive singlet oxygen (1O2) causes them by forming at all stages of cycling.(4) We discuss their detection via newly developed methods and strategies to suppress 1O2.
Na battery chemistries show poor passivation behavior with organic carbonate based electrolytes adopted from Li-ion batteries. A suitable electrolyte remains therefore a major challenge. We report an electrolyte that forms a stable solid electrolyte interface on anode materials. This permitted non-dendritic Na metal cycling with ~98 % coulombic efficiency as shown for up to 300 cycles. (7)
(1) Bruce, P. G.; Freunberger, S. A.; J.; Tarascon, J.-M.; et al. Nature Mater. 2012, 11, 19.
(2) McCalla, E.; Tarascon, J.-M.; et al. Science 2015, 350, 1516.
(3) Luo, K; Bruce, P.G.; et al. JACS 2016, 138, 11211
(4) Mahne, N.; et al. Nature Energy 2017, 2, 17036; Schafzahl, L.; et al. Angew. Chem. 2017,in press.
(5) M. Thotiyl, S.A. Freunberger, Z. Peng, P.G. Bruce, J. Am. Chem. Soc. 135, 494 (2013).
(6) N. Mahne, O. Fontaine, M. Thotiyl, M. Wilkening, S. A. Freunberger, Chemical Science 2017, 8, 6716
(7) B. Schafzahl, E. Mourad, [...], S. A. Freunberger, ACS Energy Letters, submitted.
- 2017-10-27 10:30
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