Some characteristic properties of the ionic liquids composed of bis(trifluoromethylsulfonyl)amide (TFSA−) have been discussed based on our experimental results on the electrochemical reactions of some metal species. Electrode potentials of metal species are affected by the coordination environment of the metal cations. The metal species coordinated by TFSA− is suitable for electrodeposition of the metal since the reduction potential of the species is the most positive in TFSA−-based ionic liquids. Diffusion of a charged species in TFSA−-based ionic liquids is determined not only by the size but also by the charge density of the species. Outer-sphere electron transfer reactions are sluggish due to slow dynamics of the ions of ionic liquids. On the other hand, the electrode reactions involving surface processes are considered affected by the electric double layer structure dependent on the electrode potential. The TFSA−-based ionic liquids are suggested to act as dielectric media.
The electrical performance of microbial fuel cells (MFCs) using a modified anode consisted of anthraquinone-2,6-disulfate as a mediator, polyethyleneimine as a functional polymer and graphite felt as a base material was studied. The performance of an MFC was improved using the mediator-polymer modified graphite felt anode. The maximum power density of the mediator-polymer modified MFC was reached 1.0 mW cm−2 (per geometric anode surface area), it was 2.7 times higher than that of an mediator-less MFC. The power generation of mediator-polymer modified MFC was stable for more than 10 days.
A dielectric film with high capacity is expected for the performance improvement and stabilization of electronics. Since the discovery of barium titanate (BaTiO3), a large number of studies on ferroelectric materials have been developed. In this study, we focused electrophoretic deposition (EPD) method as an easy-to-use film-forming process and examined an optimal preparation condition of the BaTiO3 (BT) and Ba0.7Sr0.3TiO3 (BST) dielectric films. In order to improve sintering performance, we used BST binder-coated slurry. The BST binder-coated slurry was dispersed into the acetone-iodine based electrodeposition bath, and thin film was prepared by EPD. The EPD was performed under various conditions; for example, deposition voltage, deposition time, amount of sample, amount of added-I2 and so on. As a result, it was found that the sintering temperature of the deposition films was able to be lowered by using BST binder-coated slurry. After annealing the film deposited for 2 sec at 100 V with 10.0 g·dm−3 BST Al2O3-coated slurry and 0.20 g·dm−3 added-I2, at 800°C for 30 min in a N2 atomsphere, showed 36.0 nF·cm−2 of capacitance density, 45 of dielectric constant, 15.2% of dielectric loss and 1.11 µm of thickness.
It is known that Fe ion emission from bipolar plate materials reduces proton conductivity and accelerates the degradation of the electrolyte membrane. In this study, we investigated the influence of cell operating conditions on Fe ion emission from S65C carbon steel, used for the anode bipolar plate, under two kinds of power generation conditions. The effects of Fe ions emitted from the bipolar plate on cell performance were also investigated. The results showed that the bipolar plate corroded significantly under a continuous low current condition. It was found that the degradation of the electrolyte membrane was dependent on not only the quantity of Fe ion emission but also the humidity in the cell. Degradation of the electrolyte membrane occurred at a lower level of Fe ion emission than the previously reported results of ex-situ tests. We conclude that controlling the cell operating conditions and increasing the thickness of the gas diffusion layer (GDL) are effective measures for reducing the degradation rate of the electrolyte membrane.