One-pot synthesis of hierarchical porous carbons with extended ultramicropores: New prospective materials for supercapacitors

ARIAS, ANALIA NATALI; VILLARROEL-ROCHA, JHONNY; SAPAG, KARIM; MORI, MARÍA FERNANDA; PLANES, GABRIEL ANGEL; FLEXER, VICTORIA; TESIO, ALVARO YAMIL

Carbon Trends

ELSEVIER

Lugar: Ámsterdam; Año: 2021 vol. 5

2667-0569

A series of carbon electrodes was synthesized via a modification of the polymerization-condensation re- action, where a 4:1 mass excess of melamine was added in basic media to the resorcinol/formaldehyde classical mixture. Melamine, together with variations of the pyrolysis temperature play a key role to de- fine the chemical and textural properties of these carbons. A high nitrogen content, ranging from 23.2 to 11.3 % was determined. A low degree of crystallinity and disordered internal structure were assessed, while a hierarchical porous structure was stablished for all samples, including an important ultramicro- porosity, with pore sizes below 0.7 nm. All electrodes showed a predominant double layer capacitive behaviour in aqueous H 2 SO 4 , while a small pseudocapacitive contribution was also evidenced for the three carbons pyrolysed at higher temperatures. These three electrodes show the highest specific capac- itance (maximum of 153.6 F g −1 ), and outstanding cycling over 10,0 0 0 cycles. A comprehensive analysis correlating morphological and surface properties and the electrochemical behaviour was carried out. The best performing carbon was selected to construct a symmetrical device for which a specific capacitance of 103 F g −1 was determined, reaching energy and power density values of 1.4 Wh Kg −1 and 111.7 W Kg −1 , respectively.