Nano-silicon based negative composite electrode for lithium-ion batteries

With the aim of improving the battery type lithium-ion batteries, many works are devoted to research of new materials for the manufacturing of high-capacity electrodes. Silicon is an attractive material as an element of negative electrode instead of graphitic carbon with its high capacity that can theoretically reach almost 3579 mAh/g (Li15Si4, ten times more than the graphite (372 mAh / g, LiC6) . However, one major problem that has prevented the development of such electrodes is the high coefficient of volumetric expansion of silicon which leads to rapid degradation of the material (cracked, spraying the electrode ,....) and its performance. In this context, the work of post-doc will be to explore the electrochemical performance of negative electrodes prepared from silicon nanoparticles synthesized by laser pyrolysis CEA. The work will be to incorporate nanoparticles in a negative composite electrode and test its performance. The understanding work will be focused on the dual influence of nanostructuration of silicon particles and of the composition / implementation of the composite electrode on the performance. Thus, this work will be located at the junction of two CEA laboratory specialists from both key points of the study (Synthesis in Saclay, development and characterization of batteries in Grenoble).

Silicon nanowire elaboration for microelectronic applications

In order to realize high capacity integrated capacitor, one approach consists in developing electrode with high specific surface. In this work, we propose to perform capacitor integrating silicon nanowires. The first part of this study will be devoted to the understanding and to the optimization of Si nanowires CVD growth process. In parallel, properties of nanowires obtained by electrochemical silicon etching will be assessed and will be compared to CVD nanowires characteristics. According to the electrical performances, different strategies (metallization Silicuration…) will be envisaged in order to enhance their electrical conductivity.

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