Enhancing the energy density of supercapacitors by introducing nitrogen species into hierarchical porous carbon derived from camellia pollen

Abstract

Heteroatom doping provides an effective strategy for boosting the capacity and energy density of carbon-based supercapacitors. In this work, we proposed an easy and feasible chemical activation method to synthesize the nitrogen, oxygen codoped hierarchical porous carbons with camellia pollen as carbon source, ammonium chloride as nitrogen source, and sodium carbonate as activating agent. The as-prepared carbon material exhibits a high specific surface area of 1049.1 m2 g−1, hierarchical pore structure, high heteroatom doping amount, and improved electrical conductivity. Benefiting from the synergistic effects of the above features, the hierarchical porous carbon exhibits a high specific capacitance (362.1 F g−1 at 0.5 A g−1), superior rate capability (178.1 F g−1 at 100 A g−1), and good cycling stability with a loss of 2.7% after 10,000 cycles. Moreover, the symmetrical supercapacitor delivers a high energy density of 31.5 Wh kg−1 at a power density of 181.0 W kg−1 and outstanding cycle stability with high capacitance retention of 93.6% after 20,000 cycles. This synthesis method provides a promising route to produce nitrogen, oxygen codoped porous carbon materials for high energy supercapacitor.