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Comportement électrochimique de matériaux à haut potentiel : LiCoPO4 et LiNi1/3Mn3/2O4, en électrodes couches minces ou composites.

Abstract : The use of unlimited natural sources such as solar, wind or hydraulic power is booming. However, their energy production is dependant of climatic conditions and is therefore intermittent. These systems are usually associated with energy storage, in order to smooth the production before injection on the network. For all these reasons, Li-ion batteries need to incorporate new electrode materials to achieve high power and high energy density while maintaining a long life and safe use.In this context, our work consisted in preparing high potential materials, LiCoPO4 (LCP) and LiNi0.5Mn1.5O4 (LNMO). The latter are perfectly integered in the context of development of materials with high energy density since they have an oxidation potential of 4.8 and 4.7 V vs Li + / Li and theoretical mass energy densities of 802 and 691 Wh.kg-1 over lithium, respectively.These materials were first synthesized in the form of thin thin films to obtain model electrodes to study the kinetics and thermodynamics properties of materials transport and interactions with the presence of a liquid electrolyte including phenomena at the electrode interface / electrolyte. The understanding acquired during this first axis allowed us to transpose and adapt these characterization techniques to more complex systems : composite electrodes.The properties of these materials with respect to lithium insertion and desinsertion have been tested and characterized in electrochemicals cells. Kinetic and thermodynamic parameters have been extracted using several electrochemical techniques such as intermittent titration (GITT), impedance spectroscopy (PEIS and GEIS), galvano-static cycling and power tests. We propose a simple method, based on power tests, to determine the diffusion coefficient of lithium. Finally, we attempt to answer several questions that remain unsolved about the capacity loss of high potential materials during long cycling, and we propose a very simple technique for improving the cycling of composites electrodes of LNMO.
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https://tel.archives-ouvertes.fr/tel-01737566
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Submitted on : Monday, March 19, 2018 - 3:40:10 PM
Last modification on : Wednesday, October 14, 2020 - 4:17:53 AM
Long-term archiving on: : Tuesday, September 11, 2018 - 7:41:44 AM

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  • HAL Id : tel-01737566, version 1

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Philippe Dumaz. Comportement électrochimique de matériaux à haut potentiel : LiCoPO4 et LiNi1/3Mn3/2O4, en électrodes couches minces ou composites.. Energie électrique. Université Grenoble Alpes, 2017. Français. ⟨NNT : 2017GREAI095⟩. ⟨tel-01737566⟩

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