Gas-phase synthesis for functional materials: Silicon for Li-ion batteries
Christof Schulz, Universität Duisburg-Essen, Duisburg, GermanyHartmut Wiggers, IVG, UDE, Duisburg, Germany
Gas-phase synthesis of nanoparticles allows to generate high purity materials with well-controlled properties in continuous flow situations that provide a chance for scale-up to industrial scale. Nanoparticles with well-controlled composition and narrow size distributions are of interest for a wide variety of applications from coatings to electronics to functional materials, e.g., for energy conversion and storage. For the synthesis of materials with desired properties, however, the reaction conditions must be well controlled and the underlying processes understood. The decomposition kinetics of vaporized metal organic compounds, the ignition properties of the mixture of these materials with oxidizing environments as well as the reaction mechanisms of the decomposition, cluster formation and the potential interaction with flame chemistry is a prerequisite for a targeted synthesis of materials.
Kinetics experiments are carried out in shock-tube reactors with optical and mass spectrometric detection of intermediate and product species, and in flow reactors with laser-based detection of temperature and species concentration. At the same time, reaction conditions such as temperature, intermediate species concentration and particle size must be determined in situ in lab-scale nanoparticle reactors as well as in pilot-plant-scale reactors to provide input and validation data for numerical simulation.
In this presentation, based chemical kinetics measurements in shock tubes, the investigation of particle formation and growth in flow reactors using molecular-beam sampling and laser based measurements of temperature as well as intermediate species concentrations will be introduced. Examples will be presented for the synthesis of silicon nanoparticles and their application in anode materials in lithium-ion batteries.