Lithium-air batteries have a very high theoretical energy density, so they have attracted much attention. However, there are various issues on practical use of Li-air batteries. Low energy efficiency is one of the issues to be solved. To improve the energy efficiency, precious metals such as Pt have been used, however, the development of the alternative catalytic materials has been required due to their high cost and limited reserves. Among the candidate as the alternative catalytic materials, nitrogen-doped carbons and transitional metal oxides are attracting attention because they show the superior electrocatalytic activity for oxygen reduction reaction(ORR)and/or oxygen evolution reaction(OER). However, to further improve these electrocatalytic properties, it very important to improve the surface area and conductivity of these electrocatalytic materials. Macroporous carbon materials including Fe-N-C bonds have superior electrocatalytic property, high surface area, and conductivity. Therefore, the macroporous carbon materials can be suitable for the electrocatalytic cathode materials for Li-air batteries. In this study, we aimed to synthesize the macroporous carbon materials including Fe-N-C bonds using Fe-Zn-based metal-organic framework(MOF)as precursor and estimate the physicochemical properties of the synthesized samples. In addition, the performance of macroporous carbon materials including Fe-N-C bonds for ORR and OER activities, and Li-air battery was also evaluated. The addition of Zn to the sample increased the Fe-N-C bonds and the active sites, resulting in an increase in the discharge capacity of the lithium-air battery.
Electrochemical measurements were used to examine effects of adding pyrimidine-derivatives(2,4-pyrimidinedione(uracil)and 5-methyluracil(thymine))and hydantoin-derivative(5,5-dimethylhydantoin(DMH))in a cyanide-free silver electroplating solution. From our research, we have discovered that the bonding energy of silver-thymine complex is greater than that of the silver–uracil complex, which leads to larger deposition overvoltage and also smaller amounts of silver deposition during the cathodic potential sweep until reaching the hydrogen generation potential.