April 17, 2015.
Rechargeable lithium ion batteries are amongst the most advanced electrical energy storage system available today. High energy lithium-ion batteries have improved performance in a wide variety of mobile electronic devices such as cell-phone and laptop computer. However, new fields of applications such as electric vehicles and large-scale stationary power require that the batteries have high durable power, high safety, long life, and low cost. Materials selection and materials processing as well as fundamental understanding regarding factors governed the materials’ properties are the key issues in the development of these advanced batteries.
Currently, two of the important directions for research in storage electrode materials in our laboratory at Khon Kaen University include (1) finding storage electrodes based on earth-abundant materials and (2) understanding the roles of nanoscale phase stability and kinetics using in situ characterization methods. Some of our recent work include in-situ synchrotron x-ray absorption spectroscopy and in situ X-ray diffraction studies of several Fe, Mn, and Si-containing compounds (which have been synthesized in various nanoscale forms). An in-depth understanding of the relationship between the structural changes and the dynamic electrochemical property of these materials will be the key to achieving new materials with high desirable performance as well as optimizing the properties of the existing ones.
Keywords: In-situ XAS, In-situ XRD, Phase Transfomation, Li-ion Battery.
Figure 1. The phase purity and crystal structure of the Li2FeSiO4 material were determined by X-ray diffraction (XRD) using Bruker D-2 diffractometer with a Cu-Kα radiation.
Figure 2. The composition of an in-situ cell for the XAS experiment which were conducted at Beamline 2.2 of the Synchrotron Light Research Institute (SLRI) at Nakhon Ratchasima, Thailand.
Figure 3. In-situ XANES spectra at the Fe K-edge during charge of Li2FeSiO4 cathode. The oxidation states of Fe ions increase from 2+ to 4+ as voltage increasing from 3.14 V to 4.48 V .
Assoc. Prof. Dr. Vittaya Amonkitbamrung
Solid State Physics Rsearch Laboratory, Dept. of Physics, Fac. of Science, KhonKaen University, Khon Kaen 40002, Thailand Tel : +66 4320 3359, Fax : +66 4320 3359
E-mail : firstname.lastname@example.org