Low-Temperature Solvothermal Method for Coal Tar-Based Carbonaceous Mesophase Preparation and Its Excellent Performance

Abstract

Carbonaceous mesophase (CM) is an important precursor of carbon materials. Its structure, preparation conditions, and post-treatment conditions determine the structure and properties of carbon mesophase materials. However, conventional methods for the preparation of CMs are complex and require high temperatures above 400 °C. In this paper, a low-temperature solvothermal (LTS) method for obtaining CMs with high-temperature coal tar as the raw material and ethanol as the solvent is presented. With the LTS method, the required temperature is reduced from 410 to 230 °C, and the process of preparing pitch by tar rectification is simplified. This method thus provides a low-energy and environmentally friendly alternative to conventional CM synthesis methods. The resulting CMs by the LTC method exhibit impressive adsorption and electrochemical properties, making them highly suitable for a wide range of applications. After activation, the CMs exhibit a significant specific surface area of 1049.336 m2/g. Additionally, they possess mesopores with an average size of 3.620 nm, which enables them to effectively adsorb and remove up to 98.25% of methylene blue. The theoretical maximum adsorption capacity of the CMs for methylene blue is 364.71 mg/g. Additionally, the activated CMs demonstrate excellent electrochemical properties. The cyclic stability of the material was evaluated, and the specific capacitance retention rate was 96.69% after 2000 cycles. These findings highlight the potential of this low-temperature solvent thermal method for synthesizing high-performance CMs and their potential use in adsorption and electrochemical applications.