Our laboratory focuses on to the research of new materials, such as High Entropy Alloys (HEAs) developed using a novel technique distinct from standard alloys, 2-Dimensional Nanomaterials derived from existing 3-dimensional materials known as MAX phases, MXenes, and Thermoelectric materials. HEAs and MXenes, in particular, have recently received significant interest in material studies, and we aim to carry out a variety of research activities that correspond with these current trends.

HEAs are alloys consisting of five or more elements in proportions ranging 5 to 35 atomic percent, departing from the conventional concept of alloys, which typically comprise a major base element and minor other elements. The high configurational entropy resulting from more than five elements leads to severe lattice distortion and slow diffusion, endowing HEAs with excellent mechanical properties such as high strength and hardness. As mentioned earlier, the number of papers on HEAs has been increasing year by year, and our laboratory is also keeping up with this trend by synthesizing HEAs via Mechanical Alloying. Moreover, we are researching aluminum-HEA composite materials to overcome the weak interfacial bonding between the base and ceramic particles in conventional ceramic particle-reinforced composites using aluminum as a compensating element, and conducting a comprehensive evaluation of their properties.

MXene is a two-dimensional nanomaterial formed from MAX phases, which are three-dimensional materials made of transition metals (M), group 13 and 14 elements (A), and carbon or nitrogen (X). By eliminating the A atomic layer from the MAX phase, MXene is formed. MXene is well-known for its strong electrical conductivity, rapid ion diffusion, and semiconductor characteristics. These outstanding electrical qualities have been demonstrated to be applicable not only to environmentally sustainable materials such as secondary batteries and hydrogen storage alloys, but also to batteries and supercapacitors. Our laboratory is undertaking systematic research on MAX phases and MXenes, and we are shifting our focus away from titanium-based MXenes and toward high-melting point metal-based MXenes.

Thermoelectric materials, which can convert heat energy into electrical energy and vice versa, are frequently employed in applications such as refrigerators. The performance of these materials is assessed using the ZT performance index, which is inversely proportional to thermal conductivity and directly proportional to electrical conductivity. Among thermoelectric materials, SnSe performs well in the intermediate temperature range (550K~800K) and has semiconductor properties. Thermal conductivity is governed by phonons in semiconductors, while electrical conductivity is governed by electrons. Based on these features, our research group is directly synthesizing SnSe via mechanical alloying and conducting research to control thermal conductivity by inserting phonon scatterers in SnSe via this procedure