Direct carbon fuel cell (DCFC) as an electrochemical device has been considered to generate electricity from coal with higher efficiency and lower air pollution issues than the traditional coal-fired power plant. The coal char as one the main carbonaceous fuel source has been successfully used in DCFC and showed good performance in different cell configurations.

Despite the advantages of DCFC, the development of this technology still has some challenges which must be addressed before becoming commercially viable. The carbon part of coal char consumed during electrochemical reaction to produce the electricity while the mineral part of it will stay unchanged after the reaction and accumulate in the system by the time. Some of these mineral matters act as the inhibitors for carbon electrooxidation and some of them play as the catalysis.

In this study, the impact of two main mineral matters exist in the coal char, alumina and silica, have been investigated in carbon electrooxidation in the half-cell setup. These mineral mixed with ternary (Li₂CO_{3 ,} Na₂CO_{3 ,} K₂CO₃ ) with the different mass ratio to obtain the optimum condition for carbon electrooxidation. In addition, the influence of silica and alumina on the melting temperature of electrolyte have been studied with TGA/DTA method to observe any changes in melting temperature or activation energy of melting.