Coral-like interconnected porous carbon derived from phenolic resin/ammonium alginate composite for high-rate supercapacitor.

A structure with ion migration channels and continuous conductive network is crucial for the rate performance of activated carbon. In this work, a phenolic resin and ammonium alginate composite derived carbon is prepared by sol-gel method, carbonization and KOH activation. Compared with pure phenolic resin derived carbon, adding ammonium alginate in carbon preparation process can form interconnected coral-like carbon structure with higher specific surface area and meso-macro pores volume. These advantages of carbon make it provide sufficient access for ions diffusion and continuous skeleton for electron transport. In addition, the morphology of carbon materials can be adjusted by ammonium alginate. A two-electrode system coupled with 6 M KOH as electrolyte is assembled to test the electrochemical properties of these carbon materials. High specific capacitances of 282.8 F g−1 and 232.1 F g−1 at 0.5 A g−1 and 100 A g−1 are obtained, respectively, with a high capacitance retention of 82%. Moreover, high energy density of 9.82 Wh kg−1 at 115 W kg−1 and conspicuous cycling stability with a capacitance retention of 95% after 20,000 cycles are showed for the symmetrical supercapacitor. This work provides reference for preparation of the 3D interconnected hierarchical porous carbon for high performance supercapacitor. [Display omitted] • Coral-like 3D interconnected morphology carbons were prepared. • Ammonium alginate as additive can improve the morphology of carbon. • The Coral-like 3D carbons showed high specific capacitance and cycling stability. • The improved electron/ion transport enhanced the rate performance of supercapacitor. [ABSTRACT FROM AUTHOR]