Many artificial graphite materials are utilized at a high temperature for smelting and refining metals, such as steel and aluminum, and for manufacturing silicon semiconductors. For such applications, it is important to understand the physical properties of these materials at high temperatures. Special instruments for measuring physical properties, such as the mechanical strength, creep, electrical resistance, thermal diffusivity and thermal expansion of artificial graphite materials from ambient to 2600 °C have been developed and are introduced here. Experimental results obtained using these instruments and their analysis are reported.

Porous carbons, as represented by activated carbon, have a high surface area and a large pore volume, together with high electrical conductivity and high chemical stability. Their superior properties over other porous materials make them ideal hosts for guest materials to produce hybrids that have intermediate properties. Organic compounds and polymers have poorer electrical conductivity and chemical stability than carbon materials, but these can be compensated for by hybridizing them with porous carbon materials. Recently, we have focused our research on the hybridization of porous carbons with redox-active materials, such as conductive polymers and redox-active organic compounds, to achieve high-performance electrochemical capacitors. These redox-active materials are located inside the pores of porous carbon host materials, and the resulting hybrids have large contact areas between the conductive carbon surface and the redox-active materials, and exhibit properties that are different from the intrinsic characteristics of both the host and guest materials. Recent advances in this research area have provided further insight into the chemical and physical properties of these hybrids. In this review, we summarize the synthesis, characterization, and evaluation of the electrochemical properties of porous carbon/redox-active material hybrids to offer new insight into our understanding of these materials.

The addition of metals to carbon materials gives it properties that are not possessed by the carbon material itself. One typical form of such an inclusion is a single metal atom with four nitrogen atoms in square planar configuration (metal-N₄ site) embedded in the π-conjugated plane, which serves as an active center of a heterogeneous catalyst. A critical factor in achieving a high activity in such a heterogeneous catalysts is the development of pores to sufficiently expose the active sites to the surface and the effective transport of reactants and products. This review describes carbon materials with the metal-N₄ site and the developed pores, which are used in energy conversion and storage devices, such as fuel cells, water electrolyzers, and redox flow batteries. The carbon materials formed by the author as a result of an original and innovative selection of the proper raw materials and synthesis procedures are demonstrated.

Although carbon fiber reinforced thermoplastics (CFRTPs) have attracted attention for automotive and aircraft applications because of their high production rate, there is concern that their thermal stability is inadequate even for automotive applications. However, some aromatic thermoplastics are known as polymers that have high thermal stability, so this study focuses on CFRTPs made with aromatic thermoplastics. If the CFRTPs are to be used for automotive and aircraft applications, they contribute to the realization of a sustainable society in terms of energy saving and decreasing CO₂ emissions. This study deals with polyethersulfone (PES), an aromatic thermoplastic, as the matrix of next generation CFRTPs, and their mechanical properties and thermal stability have been reported. It is desirable that these CFRTPs are themselves sustainable materials, if the realization of a sustainable society is to be achieved. Therefore, this study also reports on the recyclability of this CFRTP. Finally, the extremely good mechanical properties and thermal stability of this CFRTP are reported as is its good recyclability.

The capacitance and electrochemical stability of three kinds of activated carbon fibers (ACFs) with different micropore widths (0.87, 1.09, 1.30 nm) were evaluated as the electrodes of electric double layer capacitors using three sulfone-based electrolytes; sulfolane (SL), isopropyl methyl sulfone, and ethyl methyl sulfone solutions containing tetraethylammonium tetrafluroborate. The effect of ion sieving on the capacitance of the ACF electrodes and the rate performance in the SL electrolyte were more sensitive to the micropore structure compared to the conventional propylene carbonate (PC)-based electrolyte. Charge-discharge cycling tests using a two-electrode cell with the ACF electrode with the widest micopore width and a sulfone-based electrolyte were carried out with a charge cut-off voltage up to 4 V to evaluate the electrochemical stability of the electrolytes. The SL electrolyte showed a lower degradation during cycling than the PC electrolyte and the other sulfone-based electrolytes even when charged to a 4 V cut-off.