Wheel sliding, which may occur during rainy weather, is a severe problem faced by railways. The re-adhesion control method is an effective countermeasure; however, it cannot entirely prevent wheel sliding. Therefore, an increasing number of rail vehicles are equipped with a device that jets a small amount of ceramic particles toward the contact area between the wheel and rail to improve the wheel adhesion. However, no method exists to monitor the flow state of the particles in the jetting device. Therefore, we developed monitoring methods focusing on the electrostatic charging of particles passing through the device and conducted experiments using corundum and silica sands. The experimental results verified that two methods, that is, those used to analyze the electrical signals detected by the device and their integration values, are adequate to discriminate the flow state. Furthermore, we evaluated the electrostatic characteristics of the monitoring system and considered it for practical applications.

Rechargeable batteries have been used for a long time as electrical energy charging/discharging devices, and have been developed and improved still now. Here, we introduced an example of our research on the effects of high-pressure as an operating variable to improve the fast charge/discharge performance of various secondary batteries. Lead-acid batteries, nickel-metal hydride batteries, nickel-zinc batteries, and air-zinc batteries were commercially available, and they were highly safe due to aqueous electrolytes batteries. They were tested in charge/discharge performance under high-pressure to understand the typical effect of high-pressure on lowering entropy in the batteries at large currents.

We have focused on fuel cells as new clean energy to improve humanity’s future. In recent years, with the prospect of widespread use of fuel cells, it is required to establish new technologies for reducing to manufacturing process time and costs. In 2013, we began to research technologies for the mass production of MEA, with assistance from the New Energy and Industrial Technology Development Organization, which is a key component of polymer electrolyte fuel cells. In 2016, we completed development and shipped the world’s first direct coating CCM mass production equipment. We will continue to expand its business in this area, with a view to driving the growth of the overall fuel cell field and contributing to the realization of a sustainable hydrogen economy.

All solid-state lithium-ion batteries, which are expected as next-generation batteries for electric vehicles, have the potential for higher energy density than liquid-based lithium-ion batteries. On the other hand, all solid-state batteries have problems such as high reactivity of solid electrolytes, difficulty in designing electrodes and cells, and development of manufacturing process. In order to optimize the electrode and cell design, it is important to understand powder characteristics of solid electrolyte, to form the conductive path and the lithium ion path, and to form solid-solid interface. This paper describes the characteristics of solid electrolytes and all solid-state lithium-ion batteries, and evaluation and analysis techniques for solid electrolytes and all solid-state lithium-ion batteries.

In proton exchange membrane fuel cells operating with the use of Pt catalyst supported on carbon (Pt/C) cathode catalysts, severe corrosion of the carbon support has been recognized at high potentials. Highly catalytic durability with high activity is required toward the application of heavy-duty use. One of the alternative candidate catalysts are Pt catalysts supported on non-carbon ceramic supports. Our group invented that Pt catalysts supported on SnO₂ and CeO₂ without carbon additive. These catalysts were superior in durability (startup/shutdown, load cycling) and oxygen reduction reaction activity to those of commercial Pt/C by evaluation of membrane-electrode assemblies. The non-carbon support of SnO₂ nanoparticles has a unique carbon-like microstructure consisting of a fused-aggregate network structure, which enhances the electronically conducting pathways via the aggregated microstructure and gas diffusion pathways via the open pores in the microstructure. The cell performance using the Pt/SnO₂ cathode catalyst layers at operating temperatures from 80°C to 120°C is quite promising for the development of high-power density with simultaneous high durability.

In order to operate a battery, current must flow smoothly not only in the external circuit but also inside the battery to form a “current loop”. Between electrodes, in many cases, electrons and ions carry charges in the external circuit and inside the battery, respectively. Therefore, it is necessary to minimize the electrode reaction resistance and the ion migration resistance between the electrodes in order to develop highly efficient batteries. For the latter, the key technology is the development of electrolyte materials with excellent ionic conductivity in addition to shorten the distance between the electrodes. In this paper, we use fluoride ion (F⁻) conductors as an example to explain design guidelines for solid electrolyte materials that contribute to the development of high energy density batteries. In addition, applying the mechanochemical synthesis will be discussed since it has advantages to obtain novel materials that cannot be synthesized by existing methods.