Brownrigg, A. et al. (2015). In situ Fe K-edge X-ray absorption spectroscopy study during cycling of Li2FeSiO4 and Li2.2Fe0.9SiO4 Li ion battery materials. Journal of Materials Chemistry A[Online]3:7314-7322. Available at: http://www.dx.doi.org/10.1039/c4ta06305h.
In situ X-ray Absorption Spectroscopy (XAS) results are presented for Li2FeSiO4 and Li2.2Fe0.9SiO4, promising cathode materials for lithium-ion batteries. The aims are to establish the valence and local structure of Fe during charge and discharge to understand if the Fe3+/Fe4+ redox pair can be reached in the current battery design. It is found that the valence state changes between Fe2+ and Fe3+, with no evidence of Fe4+ before the onset of electrolyte degradation. There is a reversible contraction and extension of the FeO bond lengths during cycling while the FeSi distance remains constant, which underlines the stability of the Li2FeSiO4 material. The same observations apply to Li2.2Fe0.9SiO4 cathode material indicating that changing the stoichiometry does not provide any additional structural stability.
Kossoff, D. et al. (2014). Mine tailings dams: Characteristics, failure, environmental impacts, and remediation. Applied Geochemistry[Online]51:229-245. Available at: http://dx.doi.org/10.1016/j.apgeochem.2014.09.010.
Electrochromic (EC) performances of Ni3 + containing NiO thin films, called modified NiO thin films, prepared either by pulsed laser deposition or by chemical route are reported. When cycled in lithium based electrolyte, the comparison of the EC behavior of nonstoichiometric NiO thin films points out a larger optical contrast for the films synthesized by chemical route with the absence of an activation period on early electrochemical cycling due in particular to a larger porosity. Herein we demonstrate faster kinetics for modified NiO thin films cycled in lithium ion free electrolyte. Finally, X-ray absorption spectroscopy is used for a preliminary understanding of the mechanism involved in this original EC behavior linked to the film characteristics including their disorder character, the presence of Ni3 + and their porous morphology.
Conference or workshop item
Ow, J. et al. (2015). Doped apatites for novel solid oxide fuel cell applications. in:ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV - 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015.Electrochemical Society Inc., pp. 529-537. Available at: http://dx.doi.org/10.1149/06801.0529ecst.
An integrated antenna-battery was designed in order to function at 2.45GHz, with short range Bluetooth applications considered. The model was derived from a previous study in which an integrated system was first explored. The tan was investigated for the substrate and this new structure was found to give favourable gains and efficiencies compared to the previous study. Experimental parameters were also applied to the model in the presence of a dielectric material. These experimental