About the Project
In order to enhance the energy density of micro-supercapacitors (μSCs), pseudocapacitive materials such as MnO2 or electroactive polymers can be used as μSC’s electrodes. Nevertheless, these pseudocapacitive materials implemented in μSCs do not significantly boost areal energy and power densities compared to carbon based μSCs, mainly due to the limited cell voltage of pseudocapacitive material (1 V in aqueous media) regarding the carbon technology (3 V in organic electrolyte). Moreover, one attractive way to significantly improve the energy densities of μSCs when the footprint area is limited as in miniaturized devices is to improve the surface to volume ratio by developing a high specific area with a 3D scaffold. When thin films are step-conformally deposited on a 3D scaffold exhibiting high area enlargement factor (AEF), the areal capacitance of the 3D μSC is significantly enhanced at least by one order of magnitude compared to the planar one.
Based on our transdisciplinary consortium, we aim at increasing the energy density and the safety of innovative all-solid state μSCs. The strategy is to develop high surface electrodes based on pseudocapacitive materials that would be operated in severe conditions (wide temperature range, low pressure and miniaturization) thanks to specifically designed high performance solid state electrolytes, namely ionogels, providing compatibility with commonly used microelectronic fabrication processes. More specifically, interdigitated 3D electrodes will provide high areal capacitance, and further technological challenges will be addressed thanks to the solid and safe electrolytes endowed with liquid-like properties, as well as microdevice integration.
This thesis at Institut des Matériaux Jean Rouxel (IMN, Nantes) will imply close relation with partners of the consortium at IEMN Lille and ICGM Montpellier.
Main goals of the thesis:
• To prepare inorganic, organic or hybrid ionogels required to design all solid state device compatible with microelectronic process, i.e. that can sustain high temperature required for solder reflow process and that shows no leakage and can be encapsulated by standard techniques. These ionogels must be chemically and mechanically compatible with micro/nano MnO2 electrodes or other pseudocapacitive materials;
• To study electrochemical performances of μSCap (impedance spectroscopy, evaluation of performance using standard electrochemical experiments);
• To deepen the understanding and thus to rationalize the effect of confinement onto electrochemical properties (interfaces studies by means of Raman and IR spectroscopies);
• Overall, to prepare the transfer of the scientific and technical achievements to devices of interest in energy storage, miniaturization, extreme environments (space, aircarft, etc.), and / or requiring increased safety.
Profile sought: physico-chemist, the candidate will have to manipulate simple concepts and syntheses in chemistry, perform electrochemical studies, and have the willingness to deepen understanding using various physical methods.
Starting : Fall 2017 or January 2018
Monthly net salary : ~1400 € (social security included) + eventually 150 € if teaching
Supervisors : Prof. J. Le Bideau & Prof. T. Brousse
Candidates should send a detailed covering letter explaining why they are interested in the post, along with a comprehensive CV, to [Email Address Removed]. “Standardised letters” not specific to this post will not be considered. There are no restrictions to applying based on nationality, and we are a committed equal opportunities employer. There is no closing date for applications, the post will remain open until filled.
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