Source: http://www.icmcb-bordeaux.cnrs.fr/spip.php?article490&lang=fr
Timestamp: 2019-04-25 04:01:01+00:00

Document:
Keywords : Thin films ; Sputtering ; Transition metal oxides ; Transition metal sulfides ; Electrodes and solid electrolyte ; Lithium and sodium microbatteries ; Electrochemistry.
Synthesis of new functional materials : electrodes and electrolyte thin films prepared by radio-frequency magnetron sputtering. Understanding the influence of sputtering parameters on physico-chemical properties of thin films.
The significant growth of portable electronics, generally battery-powered, has triggered the race for the development of high-performance microprocessors, Systems-on-a-Chip (SoCs) or DRAM, using low power consumption integrated circuits. As a consequence, the energy supply of such optimized components can be operated today also by miniaturized power sources such thin film Li or Li-ion batteries (1 to 500 µAh). They are built up through the deposition by PVD techniques of current collectors, the positive electrode, the electrolyte and the negative electrode on a rigid or flexible substrate. Actually, about ten layers are stacked to form a complex system with a total thickness of about 10 µm. Up to now, the Li/LiPON/LiCoO2 stack that supplies a 4 V voltage is the most widespread microbattery system. Nevertheless, such an operating voltage is not the most suitable for many new emerging electronic devices, which often require significantly lower ones. The choice of the active materials (electrodes, electrolyte) depend on the specific applications of these micro-power sources and their manufacturing process. Therefore, our aim is to tailor thin film properties by tuning the sputtering parameters in order to improve the performance of each active constituent of the cell as well as the overall behavior of the microbattery. The current studies are focusing on compounds reacting with lithium according to a conversion reaction (hence having a far larger theoretical capacity), on low voltage positive electrode materials adapted to energy harvesting systems and on materials compatible with operating or manufacturing temperature (solder-reflow) higher than the Li melting temperature (181°C).
Supervision : 12 PhD students (1 currently), 8 postdoctoral fellows (2 currently), 6 master students.
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« Investigation of the local structure of LiPON thin films to better understand the role of nitrogen on their performances ». B. Fleutot, B. Pecquenard, H. Martinez, M. Letellier, A. Levasseur. Solid State Ionics, 186 (2011) 29-36.
« Characterization of all-solid-state Li/LiPONB/TiOS microbatteries produced at the pilot scale ». B. Fleutot, B. Pecquenard, F. Le Cras, B. Delis, H. Martinez, L. Dupont, D. Guy-Bouyssou. J. Power Sources, 196 (2011) 10289-10296.
« Investigation on the part played by the SEI on the electrochemical performances of the silicon electrode for lithium-ion batteries ». M. Ulldemolins, F. Le Cras, B. Pecquenard, V. P. Phan, L. Martin, H. Martinez. J. Power Sources 206 (2012) 245-252.
« High-performance all-solid-state cells fabricated with silicon electrode ». V. P. Phan, B. Pecquenard, F. Le Cras. Advanced Functional Materials, 22 (2012) 2580-2584.
« Memory effect highlighting in silicon anode for high energy density lithium-ion batteries ». M. Ulldemolins, F. Le Cras, B. Pecquenard. Electrochemistry Communications, 27 (2013) 22-25.
« Thorough characterization of sputtered CuO thin films, used as conversion material electrodes for lithium batteries ». D. Poinot, B. Pecquenard, F. Le Cras, O. Sicardy, J. P. Manaud. ACS Applied Materials & interfaces, 6 (2014) 3413-3420.
« Perfect reversibility of the lithium insertion in FeS2 : the combined effects of all-solid-state and thin film cell configurations ». F. Flamary, V. Pelé, L. Bourgeois, B. Pecquenard, F. Le Cras. Electrochemistry Comunications, 51(2015) 81-84.
« All-solid-state lithium-ion microbatteries using a silicon nanofilm anodes : high performance and memory effect ». F. Le Cras, B. Pecquenard, V. Dubois, V. P. Phan, D. Guy-Bouyssou. Advanced Energy Materials,5 (19) (2015) 1501061.
« Dual Cation- and Anion-Based Redox Process in Lithium Titanium Oxysulfide Thin Film Cathodes for All-Solid-State Lithium-Ion Batteries ». V. Dubois, B. Pecquenard, S. Soulé, H. Martinez, F. Le Cras. ACS Applied Materials and Interfaces, 9(3) (2017) 2275-2284.

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