Research

Our research lies in research fields essential for a sustainable energy cycle toward a net reduction of carbon dioxide. In this regard, as a means of storing and converting renewable energy resources into value-added chemicals, energy storage and conversion research would become more important.

We are aiming at providing a fundamental understanding of the physicochemical properties of materials together with pursuing performance enhancement in a wide range of energy-related applications such as rechargeable batteries, electrochemical capacitors, and catalysts. Apart from being into these applications, our lab is specifically interested in developing new characterization approaches that can monitor the structural changes of materials in a real-time manner (so-called "in-operando" or "in-situ"). My current research focuses on the following specific items.

1) Materials Chemistry

In the field of energy-related research, there is no success at the energy device level without a big breakthrough at the material level. Our research has focused on exploring noble materials and/or improving existing materials that can be applied to energy storage systems (e.g., rechargeable batteries, electrochemical capacitors) and energy conversion systems (e.g., water electrolysis, CO₂ conversion). Ordered mesostructured materials, 2-dimensional layered materials, and ligand-coordinated catalysts are included in my research interest.

Keywords: Materials Synthesis and Characterization

2) Catalytic Conversion as a Means of Energy Conversion

Establishing a new energy network based on renewable energy sources has been highlighted as a viable solution to various energy/environmental problems threatening humanity. However, one of the main challenges in the integration of wind/solar/tidal energies into our electric system is their intermittent availability. It is expected that energy storage and conversion systems play important and complementary roles in building up a sustainable energy cycle. In particular, it is significant that these two systems can provide a means of storing and converting energy from intermittent and transient energy resources.

Our research activity focuses on energy-dense and value-added chemical production with the use of renewable energy resources. In particular, the synthesis gas (i.e., CO/H₂) production via electrochemical CO₂ reduction reaction has been one of my main research areas. This process can be attractive as the products can be utilized as a feedstock for well-established thermocatalytic reactions (e.g., Fisher-Tropsch, Alcohol synthesis). Experimental and theoretical investigations, which can lead to a fundamental understanding of its competitive nature against hydrogen evolution reaction and discovery of novel catalyst materials, are being conducted. Moreover, We are aiming at the development of electrocatalytic systems capable of high-yield production mediated by CO₂/CO/H₂, etc. Other gas-mediated electrocatalytic systems will be included in our future research.

Keywords: Energy Storage (Rechargeable Batteries), Energy Conversion for Alternative Fuel Production (Electrocatalysis using CO₂/CO/N₂/H₂O etc.)

3) Synchrotron X-ray Analyses

Synchrotron-based X-ray analyses have been widely adopted in various research fields because they can offer non-destructive and high-resolution probing compared with typical laboratory-based X-ray analyses. Therefore, these analyses enable us to identify the chemical/physical information on our materials even under in-operando conditions.

Our research has been focused on revealing the structure-property relationship by using X-ray scattering (X-ray diffraction, Small-angle X-ray scattering) and X-ray absorption fine structure (XAFS) analyses in a complementary manner. Especially, a combination of XRD and XAFS has been effective in providing insights into the structural evolution and electronic property variations under various conditions such as temperature, gas, and electrochemical potential.

Keywords: In-situ X-ray Characterization, Structural Refinement, X-ray Crystallography, X-ray Absorption Fine Structure,