PhD subjects

Dernière mise à jour : 19-11-2017

INAC

«««

• Ultra-divided matter, Physical sciences for materials

 

SiNW composites in high energy density lithium-ion batteries

SL-DRF-18-0291

Research field : Ultra-divided matter, Physical sciences for materials
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SyMMES)

Synthèse, Structure et Propriétés de Matériaux Fonctionnels (STEP)

Marcoule

Contact :

Cédric HAON

Pascale CHENEVIER

Starting date : 01-10-2018

Contact :

Cédric HAON

CEA - DRT/DEHT//LCB

04 38 78 34 71

Thesis supervisor :

Pascale CHENEVIER

CEA - DRF/INAC/SyMMES/STEP

04 38 78 07 21

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.

 

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