Abstract

This study introduces a hydrothermal-assisted method that utilizes a solvent-saturated vapor atmosphere (SSVA) technique to significantly improve the synthesis efficiency and textural properties of polybenzoxazine (PBZ)-derived porous carbon. The creation of a high-temperature, high-pressure environment reduced the gelation time for PBZ sol-gel synthesis from 48 h to merely 3 h. The assistance of high temperature and pressure facilitated sol-gel polymerization at 150 °C by suppressing solvent volatilization and allowing for the generation of internal pressure. Investigations into pre-polymerization time and monomer concentrations highlighted their critical roles in determining the textural properties of the resulting porous carbon. An extended pre-polymerization time increased crosslink density, which led to an increase in specific surface area (from 400 to 573 m² g⁻¹) and pore volume (from 0.56 to 1.06 cm³ g⁻¹). Optimizing monomer concentrations enhanced gel stability and density, thereby improving textural properties. The pyrolysis and activation processes further influenced pore structure and heteroatom content. Higher pyrolysis temperatures (700–900 °C) increased pore volume (from 0.93 to 1.20 cm³ g⁻¹) while decreasing heteroatom content. Chemical activation with zinc chloride achieved the highest specific surface area (1234 m² g⁻¹) and pore volume (1.90 cm³ g⁻¹), along with notable heteroatom contents (6.89 % N, 3.78 % O). These superior textural properties, combined with impressive electrochemical performance (227 F g⁻¹ at 0.25 A g⁻¹) and long-term stability (100.17 %) over 10,000 cycles, highlight the potential of hydrothermal-assisted synthesis for producing porous carbons designed for energy storage applications.