Synthesis of carbon dioxide-derived carbon using a reducing agent and utilization

Abstract

Recently, Carbon dioxide (CO$_2$) is one of the main causes of global warming, and many researchers are trying to find ways to reduce carbon dioxide. In these studies, two main ways of reducing carbon dioxide emissions or dealing with captured carbon dioxide have been studied. In the emission reduction, eco-friendly electric energy is used as an alternative to fossil fuels, which are the main source of CO$_2$, and in the latter case, carbon dioxide capture and utilization (CCU) technology is used to capture CO$_2$ and convert it into other chemicals. However, there are several problems with the commercialization of these methods. First of all, the use of electrical energy requires improved generation methods and a next-generation energy storage system that can efficiently store energy produced. In addition, carbon dioxide is a chemically stable molecular structure, making it difficult to convert under mild conditions. As a result, there have been studies to convert supercritical carbon dioxide by applying high pressure or heating, but the additional cost problem will be a major challenge for commercialization. Therefore, the appropriate technology for carbon dioxide utilization should be found by comparing the conditions under which carbon dioxide is converted with the corresponding costs and the value of the product. This dissertation concentrated on the study of conversion CO$_2$ into carbon material and utilization CO$_2$-derived carbon as a material for energy storage systems. These studies have the advantage of using CO$_2$ as a raw material for high-valued carbon production, while improving the efficiency of energy storage systems. In this conversion, CO$_2$-derived carbon materials were synthesized by converting CO$_2$ under moderate conditions compared to conventional conversion methods through reactions with reducing agents. As a result, the boron-doped porous carbon and graphitic porous carbon were synthesized, which were utilized as electrode materials for lithium-sulfur batteries. These CO$_2$-derived carbons show higher electrochemical performance than conventional carbon. In addition, the properties of each electrode material were considered to be effective in improving the performance of lithium sulfur batteries.