Abstract
Silicon negative electrode for lithium ion battery was designed in the form of self-organized 1D core-shell nanotubes to overcome shortcomingslinked to silicon volume expansion upon lithiation/delithiationtypically occurring with Si nanoparticles. The negative electrode wasformed on TiO2 nanotubes in two step electrochemicalsynthesis by means of anodizing of titanium and electrodeposition ofsilicon using ionic liquid electrolytes. Remarkably, it was found thatthe silicon grows perpendicularly to the z-axis of nanotube andtherefore its thickness can be precisely controlled by the charge passedin the electrochemical protocol. Deposited silicon creates a continuousSi network on TiO2 nanotubes without grain boundaries andparticle-particle interfaces, defining its electrochemicalcharacteristics under battery testing. In the core-shell system thetitania nanotube play a role of volume expansion stabilizer frameworkholding the nanostructured silicon upon lithiation/delithiation. Thenature of Si shell and presence of titania core determine stableperformance as negative electrode tested in half cell of CR2032 coincell battery.