Heteroatom Incorporated Carbon Materials

In recent years, carbon materials have emerged as promising materials for wide range of energy related applications such as photo and electrocatalytic water splitting, super capacitators, batteries and water cleaning, due to their superb conductivity, strong mechanical strength, and thermal conductivity. Introduction of heteroatoms such as boron, nitrogen, sulfur and phosphorous into the carbon network, enables the tuning of various properties (conductivity, oxidation stability, and catalytic activity) only by changing the heteroatoms amounts inside the carbon matrix. For example, an electron rich carbon is formed, by incorporating boron which has lower electronegativity than carbon, and by further incorporation with nitrogen, that due to size differences creates structure deformations within the carbon matrix creating more electrochemically reactive sites, creating a BCN (boron-carbon-nitrogen) material which is active in several (photo)electrochemical reactions.

Usually the synthesis of these materials is carried out in gaseous or solid state reactions. Although a wide range of materials were synthesized by these reactions there are several drawbacks. Gaseous methods are expensive (due to the use of metallic catalysts) and exhibit very low scalability, while in the solid state reaction it`s very hard to control the elemental composition of the final materials and the use of hard/soft templating is usually needed. Herein we show a new, scalable and easy way to synthesize heteroatom incorporated carbon materials by means of molten state intermediate. This method enables the synthesis of BCNO, CS, and CS with transition metals. The elemental composition is easily controlled within these materials (up to 30% boron, 20% sulfur, and 30% nitrogen) resulting in fine tuning of the materials properties. For example, by using different molten precursors such as ammonia – borane and polycyclic aromatic hydrocarbons (namely pyrene) we are able to synthesize BCNO materials. In addition, these materials exhibit good capacity values as anode in a Li-ion battery.