Silicon-based Batteries: Periodic Nanostructuration for enhanced properties

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Increasing the silicon content in Li-ion battery anodes is a target and a challenge. The capacity of Si is ten times higher than in graphite but the durability is a bottleneck. Indeed, during lithiation, the alloying reactions induce volume variations of the order of 300%, generating significant stress and rapid degradation of the electrode. There is a consensus on the interest of using nanostructured silicon for increasing the durability of the Li-ion battery anodes. Nevertheless, improvement of performance has been uneven and the reasons for these discrepancies have not been fully apprehended. Our hypothesis is that the nanostructuration needs to be organized and, even better, periodic. The proposed research program aims at boosting the performance of silicon-based electrodes for Li-ion batteries by electrodes by a design of materials inspired by the topology of cellular materials with exceptional mechanical properties. Therefore, the general idea of this program is to optimize the mechanical properties by organizing the porosity of silicon nanostructures. The strategy consists of i)Designing porous periodic Si with increasing complexity, from organized, periodic mesoporous silicon to Triply Periodic Minimal Surfaces (TPMS) using different synthesis methods; ii)Modelling, characterizing and optimizing their mechanical properties; iii)Testing the electrochemical properties and characterizing the electrochemically-induced effects on our optimized structures. The overall objective is validating our working hypothesis and delivering a proof of concept that will definitely trigger a larger amount of research and development activities to produce better structured porous architectures and increase the Si content of a composite anode for Li-ion batteries to a maximum possible value, by following our guidelines and roadmap. Ten HQPs (3 PhDs, 2 Mscs, 5 interns) will benefit from training on a cutting-edge research topic in the field of energy materials field.