A controllable self-template synthesis strategy for hierarchical porous carbon microspheres with cavity structures for supercapacitor applications

Herein, we introduce a novel and controllable self-template approach for fabricating hierarchical porous carbon microspheres with cavities (CPCMs). This approach uses polyacrylonitrile (PAN) and acrylamide (AM) microspheres as templates, which feature small anisotropic bumps on their surface. These bumps are encapsulated by divinylbenzene (DVB) during the coating polymerization process. The subsequent hydrolysis of PAN and AM led to the formation of a hierarchical porous structure. Specifically, mesopores mainly arose from PAN hydrolysis, whereas AM contributed additional micropores and macropores, generating an intricate pore structure within the DVB shell. This method differs from traditional pore-making approaches. Additionally, in situ doping of nitrogen (N) and oxygen (O) atoms was achieved. The amount of DVB coating can be adjusted to vary the shell thickness, allowing for the modulation of the pore size distribution and surface micromorphology. Owing to the synergistic effects of an ultrahigh specific surface area (1151.9 m ² g ⁻¹), extensive pore volume (1.2575 m ³ g ⁻¹), and well-structured micro-meso-macropore hierarchy, along with N/O codoping, the resulting carbon material exhibited outstanding electrochemical energy storage performance. Notably, the optimal CPCMs-2 electrode achieves an exceptional specific capacitance of 377 F g ⁻¹ at a current density of 0.5 A g ⁻¹. This study proposes a novel avenue for designing hierarchical porous carbon materials, and CPCMs could be expanded to a wide range of applications.