Personal web page : http://inac.cea.fr/Pisp/pascale.chenevier/
Laboratory link : http://inac.cea.fr/symmes/
More : http://liten.cea.fr/cea-tech/liten
The lithium-ion battery (LiB) technology, used for portable electronics as well as electrical vehicles, is based on continuously changing materials to improve their energy storage capacity, life span and safety. Silicon is interesting as an active material because it can absorb up to 10 times more lithium than carbon, the usual material in the negative electrode of commercial LiB. Besides silicon can be mixed with carbon in the electrode. Only silicon in the form of nanosized particles or wires can make long-standing battery electrodes, because mechanical constraints during the charge/discharge cycles induce silicon fracturing into disconnected powder. But on the other hand, nanosized silicon offers a large surface area to surface side-reactions, leading to lithium immobilization and performance loss.
In the present PhD project, two recent CEA technologies will be associated: a method for silicon nanowire growth at large scale (patents 2014-2016), and a process for making silicon-carbon composites in which nanosized silicon is embedded in carbon microparticles. The student will be in charge of material synthesis, characterization and performance tests in LiB. In order to optimize synthesis processes and LiB life span, he/she will try to understand the reactivity of all components of the composite during LiB cycling by electronic microscopy, spectroscopy and electrochemistry.