Controlled Synthesis of Carbon Nanospheres via the Modulation of the Hydrophilic Length of the Assembled Surfactant Micelles

A co-polymerization-carbonization method was employed to synthesize porous carbon nanospheres (PCNSs) using pyrrole-aniline polymers as a carbon source and alkyl phenol non-ionic surfactants as templates. The effect of the hydrophilic length on the carbon nanosphere size was systematically investigated. The so-prepared PCNSs were characterized via high-magnification scanning electron microscopy, dynamic light scattering (DLS) analysis, and N₂ adsorption and desorption analysis. The results indicate that the obtained nanosphere diameter can be tuned by changing the length of the hydrophilic groups. The length of the hydrophilic groups mainly affects the size of the vesicles or micelles formed by the assembly of the surfactant in solution, as was verified by the DLS results. After activation by KOH, the typical sample EO(30)-PCNS has a high specific surface area of 2137 m²/g and a large pore volume of 1.76 cm³/g. Electrochemical tests in 6 M KOH demonstrated that the assembled EO(30)-PCNS supercapacitor electrode displays good capacitive properties, such as a high specific capacitance of 221 F/g at 1.0 A/g and a good rate capacity of 68% retention at 10.0 A/g. This finding suggests that the uniform particle shape and high specific surface area are beneficial for the ion transportation, leading to good electrochemical performances. Our work provides a novel synthetic strategy for the fabrication of carbon nanospheres or other nanosphere materials for the construction of high-performance supercapacitors by optimizing few parameters, such as the length of the hydrophilic or hydrophobic groups of the surfactants.