Nano-Electrochemistry: Electrochemical Synthesis Methods, Properties and Characterization Techniques

Understanding the correlation between changes in the microscopic structure, ordering and performances is one of the main motivations of this chapter. Establishing new protocol for nanomaterials characterization of functional materials is an important step in our knowledge. The robust approach for nanomaterial characterization here presented, combining different state-of-the-art techniques, is suitable for applications in structural refinements of nanocrystalline functional system, including those for energy-related applications. Several techniques are presented to study microscopic properties of nanomaterials, including XAS (X-ray Absorption Spectroscopy) ex-situ and in-situ, XRD (X-Ray Diffraction), high resolution TEM (Transmission Electron Microscopy), and XRF (X-Ray Fluorescence). In particular the site-selective XAS (performed at international synchrotron radiation facilities) sensitivity to the local structure (up to $5-10$ AA around photoabsorbing sites) is used for characterization of the nanomaterials with unprecedented accuracy. Two examples, an investigation of the local structure and chemical disorder of a commercially available Pt-Co alloy nanocatalyst electrodes used in proton exchange membrane fuel cells and the synthesis and structural characterization of a nickel doped cubic manganese spinel LiNi$_{0.5}$Mn$_{1.5}$O$_4$ for application as cathode material in secondary lithium batteries will be discussed.