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I. Electrochemical Energy Storage/Conversion System
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The necessity of energy storage/conversion system became increasingly significant as the time-wise balance between energy production and consumption turned into one of the most important components of the next generation powering matrix (so-called Smart Grid). Although the demand surges, energy storage devices and conversion systems have not been satisfactory in terms of scalability and efficiency.
Among various types of energy conversion/storage systems, electrochemical energy systems such as fuel cells and batteries have many intrinsic advantages because of their scalability (usable both for mobile devices and grid-level energy systems) and high conversion efficiency. Many efforts are being made to overcome current technical issues and to improve power/energy density and economic feasibility.
By reversing the electrochemical process in a fuel cell operation where oxygen and hydrogen combine into water, one can split water molecules back to oxygen and hydrogen. The hardware for the fuel cell operation can be used in either an energy generating or an energy storing system. For example, in a mixed system composed of a solar cell and a fuel cell, the redundant energy generated by the solar cell during daytime can be stored through the reverse fuel cell, and the stored energy is consumed through the fuel cell during nighttime. This system can specifically be more useful in cases where a stand-alone energy sourcing system is needed for isolated devices, buildings and/or micro-grids.
In our laboratory, we focus on the followings.
- Revelation of major factors determining charge transfer reaction rate at the electrode/electrolyte interfaces via both macro- and nano-scale observations.
- Revelation of degradation process in electrochemical cells through various experimental tools as well as multi-scale simulations.
- Prototyping a high-performance electrochemical cell based upon the accumulated observations/understandings.
The application of focus is mostly on solid oxide based regenerative fuel cell for now but will be extended to other electrochemical energy devices such as Li-based batteries, flow batteries and super-capacitors.
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II. Next-Generation Data Storage
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As further scaling of Flash devices is reaching the physical and technical limits, alternatives to the conventional device have attracted considerable attention. Many alternatives including resistive-switching memory and electrochemical metallization memory are being actively studied with particular focus on increasing the writing speed, endurance and decreasing the read/write voltage, but much of the switching mechanisms have not been clearly understood. Scanning probe can be a useful tool for this purpose considering it can provide prototypical assessment without implementing a full device and the size of a scanning probe is similar to the targeted bit size (a few nm - a few tens of nm).
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