Electrochemically active porous carbon nanospheres prepared by inhibition of pyrolytic condensation of polymers

• Published in: Proceedings of the National Academy of Sciences - PNAS 2023-05, Vol.120 (19), p.e2222050120-e2222050120
• Main Authors: Kim, Jaehyun, Lee, Dayoung, Kim, Cheolho, Lee, Haeli, Baek, Seungjun, Moon, Jun Hyuk
• Format: Article
• Language: English
• Subjects: Capacitance; Carbon; Chemical treatment; Condensates; Condensation polymerization; Density; Electrochemistry; Etching; Nanospheres; Physical Sciences; Pneumatics; Polymers; Polystyrene; Polystyrene resins; Porosity; Specific volume; Thin films; Zinc oxide
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2222050120

Porous carbon is a pivotal material for electrochemical applications. The manufacture of porous carbon has relied on chemical treatments (etching or template) that require processing in all areas of the carbon/carbon precursor. We present a unique approach to preparing porous carbon nanospheres by inhibiting the pyrolytic condensation of polymers. Specifically, the porous carbon nanospheres are obtained by coating a thin film of ZnO on polystyrene spheres. The porosity of the porous carbon nanospheres is controlled by the thickness of the ZnO shell, achieving a BET-specific area of 1,124 m /g with a specific volume of 1.09 cm /g. We confirm that under the support force by the ZnO shell, a hierarchical pore structure in which small mesopores are connected by large mesopores is formed and that the pore-associated sp defects are enriched. These features allow full utilization of the surface area of the carbon pores. The electrochemical capacitive performance of porous carbon nanospheres was evaluated, achieving a high capacitance of 389 F/g at 1 A/g, capacitance retention of 71% at a 20-fold increase in current density, and stability up to 30,000 cycles. In particular, we achieve a specific area-normalized capacitance of 34.6 μF/cm , which overcomes the limitations of conventional carbon materials.