Silicon nanoparticle/carbon nanotube composites for LI-ION battery anodes

Abstract

In the context of high demand for energy in mobile devices, many studies deal with the lithium-ion cell technology. Because of its larger uptake ability of Li, silicon was suggested for being used (combined with a conductive material) instead of graphite, currently the most frequently used anode material for combining good electrical conductivity and the ability to host Li as intercalated ions between the graphenes [1,2]. However, charge/discharge cycles induce fatal structural damages to bulk Si, as a consequence of successive swellings then shrinkings of the Si lattice [3]. Hence bulk graphite and/or Si anode materials could be replaced by nanostructured composites combining mechanical strength, electrical conductivity, and high charge capacity. Carbon nanotubes mixed with silicon nanoparticles appear as a promising material [4-6]. Here, multi-walled carbon nanotubes Graphistrength® were used as substrate for the Fluidized Bed Chemical Vapour Deposition (FBCVD) of silicon from silane (SiH4). The paper describes the synthesis and characterisation of the nanostructured composite material obtained, as well as the results of the electrochemical tests (involving chargedischarge cycles) carried-out to analyze their behavior as Li-ion cell anodes.