Precisely controlled synthesis of mesoporous carbon spheres via a surfactant-free “time-dependent” strategy for supercapacitors

Abstract

Mesoporous carbon spheres (MCS) with controllable morphology and pore structure have received extensive attention. However, precise regulation in the absence of surfactants remains a challenge. Herein, a “time delay” strategy to prepare hollow, solid and yolk-shell mesoporous carbon spheres with precise tunable large pore sizes is first reported. The mesoporous size of more than 11.32nm is achieved in the absence of surfactants by delaying the initial hydrolysis time of tetraethyl orthosilicate (TEOS), changing its concentration distribution in the system, so as to realize the co-condensation assembly with resorcinol. In addition, by simply regulating the initial hydrolysis time of TEOS, adjusting the degree of condensation of resorcinol, the internal morphology and structure of the carbon spheres are precisely regulated, and the specific surface area of more than 676 m2 g–1 is displayed. The large mesoporous and controllable structure enables the electrode prepared with this MCS to have a capacitance of up to 243Fg–1 and a capacitance retention of 91% in a two-electrode system, showing its application advantages as an electrode material in the field of electrochemistry.