Resorcinol-formaldehyde resin based porous carbon materials with yolk-shell structure for high-performance supercapacitors

• Unique RF resins with yolk-shell structure were obtained without any template.
• The resin based porous carbon with yolk-shell structure had quite high capacities.
• The large cavity inside the yolk-shell RF is in favor of electrolyte ion to transfer.

Novel yolk-shell structure of resorcinol-formaldehyde resin (YRF) is formed via the condensation polymerization of resorcinol and formaldehyde at 0 °C without any template. After carbonized and activated with KOH at 700 °C, the YRF based porous carbon materials are obtained and the unique yolk-shell structure is remained. The specific surface area of the porous carbon materials is up to 1218 m2 g−1 through the N2 adsorption-desorption method and many micropores and mesopores are formed in the carbonized materials which are beneficial for electrolyte transport. The specific capacitance of porous carbon material YRFC700-1:3 reaches 397.4 F g−1 at the current density of 0.5 A g−1 and the capacitance retention is 91.2% after 10,000 charge-discharge processes at large current density of 20 A g−1. The strategy developed in this work provides a good example for making full use of polymer-based carbon materials. The good electrochemical performance demonstrates that the polymer-based carbon materials may have promising applications in high-performance of energy-storage devices.