Caccami, M. et al. (2017). A Tightly Integrated Multilayer Battery Antenna for RFID Epidermal Applications. IEEE Transactions on Antennas and Propagation[Online]. Available at: http://dx.doi.org/10.1109/TAP.2017.2780899.
For the acceptance 1 of biointegrated devices in daily life, radio systems must be developed, which are minimally invasive to the skin, and they must have ultralow-profile local power sources to support data-logging functionality without compromising shape conformability. This contribution proposes a tightly integrated multilayer battery-antenna system (65 × 23 mm2), that is, ultrathin (just 200 μm), flexible, and lighter than 1 g, making it suitable for epidermal applications. The negative electrode (anode) current collector of the battery is a radio frequency identification tag antenna coated by a conductive polymer (Pedot:PSS) working as anode material. Since the battery is a dynamic device, subjected to discharging, the antenna design must include the variable dielectric properties of the conductive polymer which are here first characterized in the UHF band for real charge/discharge battery conditions. The communication performance of the prototype composite device is hence evaluated through the measurement of the realized gain of the tag antenna (−19.6 dBi at 870 MHz) when it is placed directly onto a volunteer's forearm. The read range of 1.3–3 m is suitable for occasional data download from the epidermal data logger when the user comes close to a reader-equipped gate.
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 Fe–O bond lengths during cycling while the Fe–Si 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.
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