David Munaò

Silicon-based nanocomposite for advanced thin film anodes in lithium-ion batteries

This work describes the preparation and the characterization of Si-based nano-composite anodes. The samples are prepared by a unique combination of two techniques: Laser Assisted Chemical Vapor Pyrolysis and Electrospray Deposition. The former is used to synthesize the active material, while the latter is employed for the deposition of thin electrode layers onto stainless steel supports. The silicon nano-particles characterization indicates a well-defined crystalline structure and a homogeneous, spherical-like morphology. The electrochemical measurements performed using the silicon-based electrode in the lithium cell show a maximum specific capacity of the order of 1200 mA h g−1 and a good rate capability. The initial irreversible capacity associated with this class of materials is strongly reduced by preliminary surface treatment. The morphology changes upon cycling are minimal and no extended fractures are observed for the cycled electrodes, thus finally indicating the validity of our silicon based electrode as an anode for advanced lithium-ion batteries.

Synthesis of Silicon Nano-particles for Thin Film Electrodes Preparation

The present work concerns novel approaches to fabricate silicon-based electrodes. In this study silicon nano-particles are synthesized via two aerosol routes: Laser assisted Chemical Vapour Pyrolysis (LaCVP) and Spark Discharge Generation (SDG). These two techniques allow the generation of uniformly sized particles, with a good control over the composition and the range of sizes. Herein, particles with size ranging from 2 to 70 nm were obtained. Starting from these nano-particles, nano-structured porous thin films are produced either by electrospraying a polymeric solution in which LaCVP-produced particles were previously dispersed, or by inertial impacting the SDG-produced particles directly from gas phase onto a substrate. The Electro- Spray (ES) is used to produce composite films for Li-ion battery applications, whereas the Inertial Impaction (II) is used to produce pure silicon films for other purposes (i.e.: sensors).