A hierarchical domain structure analytical method is introduced with a basic definition of cluster, microdomain and domain as the structural units for synthetic carbons. The differences between graphitizable and non-graphitizable carbons are possibly understood due to the difference in the fused inter-connection states of microdomains and the difference in domain size that is derived from it. KOH and steam activated carbons, which differ in the diffusion of the activation agent into the domains of the precursor during activation, have different domain sizes, which results in different specific surface areas, pore volumes and activation yields. It is highly expected that a better understanding of the structure of synthetic carbon based on this hierarchical domain structural model can give more possibilities for improving the performance and functionality of synthetic carbons in terms of their properties.

Lithium-ion batteries (LIBs) are widely used in mobile devices and electric vehicles (EVs). One of the problems of LIBs for EV-use is inferior low-temperature performance. At low temperatures, the performance of a conventional ethylene carbonate (EC)-based electrolyte solution is degraded due to its high melting point. However, propylene carbonate (PC) that is a candidate with a low melting point cannot be used with a graphite negative electrode. In order to adapt the PC-based electrolyte solution to the graphite negative electrode, the solvation structure of lithium ions was controlled by the addition of a Lewis acid and Lewis base. In this review, the design concept of the PC-based electrolyte solution and the control of the solvation structure of lithium ions are introduced.

The electrochemical behavior of some carbonaceous materials in alkaline aqueous solutions are discussed. Carbon black, which is mixed as an electro-conductive additive, has a catalytic activity for the oxygen reduction reaction (ORR) in alkaline solutions. Following the initial 2-electron reduction on carbon, metal-oxide catalysts decompose the intermediate HO₂⁻ to form OH⁻ and O₂. Graphite forms graphite intercalation compounds (GICs) containing OH⁻ in alkaline solutions with a high ionic strength, while the formation of GICs was not observed in the solutions with a low ionic strength.

Textiles using multi-wall carbon nanotube (MWCNT)-coated conductive fibers are expected to be used for wearable applications as heaters with flexibility and light weight. Impregnating a low viscosity paste blend of a low concentration of carbon black (CB) in dimethyl silicone oil (SO), instead of indurative Ag paste, between the conductive textile and a metal wire having area of 5×130 mm, while retaining flexibility, resulted in an order of magnitude reduction of the electric contact resistance after two days. The remarkable reduction with time was found to be generated by a synergistic effect of a network of CB particles gradually induced by liquid SO flow at 30 °C and an increased CB concentration produced by slow penetration of SO into the surrounding textile.

Activated carbon (AC) was prepared from petroleum coke (PC) by KOH activation and characterized with N₂ adsorption-desorption isotherms and elemental analysis. Pore development was promoted by increasing the KOH/PC mass ratio, and a high surface area of more than 3000 m²/g was obtained using KOH/PC with a mass ratio of 4 or more. Similar pore properties were obtained for a low sulfur-containing petroleum coke (LSPC). Although the sulfur content of PC was decreased by KOH activation, the reduction of sulfur had little effect on the pore development. The prepared ACs were further oxidized by an ammonium persulfate solution and used for a Cd(II) adsorption experiment. A large amount of Cd(II), about 1.7 mmol/g, was adsorbed by oxidized AC prepared from KOH-activated PC with a surface area of 1700 m²/g.

High-performance lubricating additives are necessary to improve the properties of lubricating fluids for boundary lubrication in which the lubricating conditions are more severe. Since graphene oxide (GO) has many oxygen functional groups even on its basal plane, it is likely that it can be easily adsorbed on steel surfaces and act like a lubricating additive similar to a fatty acid. In addition, the GO is very thin. Thus, it is thought that GO acts as a thin friction interface for boundary lubrication. These properties of GO can help achieve low friction and wear by preventing direct contact between the friction interfaces which would lead to high friction and wear. In this review, experimental results of friction tests involving GO dispersions in water and lubricating oils are introduced. The experimental findings show that GO has superior frictional properties as lubricating additive for boundary lubrication. Tribofilm formation and/or GO insertion between the friction interfaces are necessary to achieve low friction and wear.