Preparation of asphalt-based microporous organic polymers with sulfur bridges

Abstract

The construction of microporous organic polymers (MOPs) with sustainable building blocks is essential for their scale-up preparation and practical applications. Both asphalt and sulfur are massive by-products of the petroleum industry, which are hardly employed for the synthesis of MOPs simultaneously. Here, we develop a new family of MOPs combining asphalt with sulfur via one-pot and catalyst-free polymerization using simple programmed thermal treatment. During the polymerization process, asphalt acts as a rigid building block and is chemically cross-linked by a short sulfur bridge, and thus permanent porosity is introduced into the obtained polymers. The influence of sulfur dosage on the surface area of the obtained MOPs has been investigated in detail. It is found that a maximum surface area of 598 m² g⁻¹ is achieved when the ratio of asphalt to sulfur is 8 : 2. The versatility of the formation of asphalt-based microporous organic polymers with sulfur bridges is also confirmed by employing other commercially available asphalt samples. In the following carbonization process, the sulfur-containing precursor is converted into carbon materials with a high sulfur content and surface area. The electrochemical performance of this sulfur-doped carbon material demonstrates a capacitance of 372 F g⁻¹ at a current density of 0.5 A g⁻¹ and excellent cycling stability after 10 000 cycles. Therefore, the resultant sulfur-doped carbon material exhibits excellent electrochemical performance and the adoption of new building blocks and the polymerization strategy will significantly promote the development of MOPs.