Ion-matching porous carbons with ultra-high surface area and superior energy storage performance for supercapacitors

Abstract

High specific surface area and rational pore size distributions (PSD) are considered to be important factors in improving the electrochemical performance of porous carbons in supercapacitors based on the electric double layer (EDL) mechanism. In this work, a series of polypyrrole (PPy)-derived porous carbons (PPCs) are synthesized via a facile and scalable strategy. An ultra-high specific surface area of 4091.54 m2 g−1 with a high pore volume of 2.334 cm3 g−1 is achieved via rational regulation of PSD by simply adjusting the carbonization temperature. When used as electrode materials for supercapacitors, the PPCs carbonized at 700 °C (PPC-700) deliver excellent specific capacity (397.9 F g−1 at 1 A g−1), rate capability (224.0 F g−1 at 100 A g−1) and cycling properties (capacity retention of 95% after 30\u2006000 cycles at 10 A g−1). PPC-700 has also been demonstrated to possess encouraging capacitances (308.8 F g−1 at 1 A g−1 and 156.0 F g−1 at 20 A g−1) and a high energy density of 97 W h kg−1 at 1 kW kg−1 in ionic liquid electrolytes. Such excellent electrochemical performance of the as-synthesized PPCs is attributed to the high pore volume and micropore content leading to an ultra-high specific surface area and the rationally controlled micropore size to match the ion diameter of the electrolytes.