S. Melinte*

ICTEAM, Université catholique de Louvain, Place du Levant 3, Louvain-la-Neuve, 1348 Belgium
*Contact: [email protected]

Studies on emerging energy conversion and electro-chemical storage technologies are determining to solve the economic, social and environmental challenges of the energy sector.  Silicon has been recently in the spotlight of the next generation anode materials for Li-ion battery industry due to its distinctive Li-related features such as the ability to form lithium rich compounds, corresponding to an exceptional capacity of 3579 mAh/g at low working voltages.  In exchange, many engineering concerns are associated to the structural deformation during lithium alloying that can lead to material pulverization as well as limited cycling life.
We'll detail on an anode configuration accommodating interconnected kinked Si nanowires fabricated by metal assisted chemical etching.  We'll emphasize the importance of the metal assisted chemical etching method for the synthesis of advanced Si nanostructures.  The electrochemical evaluation of the three-dimensional kinked Si nanowire-based anode assemblies shows valuable cycling life in ionic liquids compared to conventional electrolytes, retaining 80% of the initial capacity and displaying an average Coulombic efficiency of 98% after 100 cycles.  We'll report on three-dimensional interconnected Si-based aerogel systems relying on silicon nanoparticles trapped within highly porous, electronically active multi-walled carbon nanotube frameworks as Li-ion battery anodes.  We'll further focus on flexible Li-ion batteries and analyze nanotechnology approaches for improving their performances via Si-built anodes.  An approach to roll out Li-ion battery components from silicon chips by a continuous and repeatable etch-infiltrate-peel cycle will be presented.  Using this process we demonstrated an operational 3.4 V Li-polymer metal@silicon nanowire battery, which is mechanically flexible and scalable to large dimensions.  The influence of the metal shell morphology and thickness on swelling and fracture modes of the crystalline silicon nanowires will also be presented.

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