Outstanding capacitive performance of ordered mesoporous carbon modified by anthraquinone

Ordered mesoporous carbons (OMCs) is one of the most promising electrode material for supercapacitor. However, pure OMCs have low specific capacitance due to its simplex storage mechanism based on electric double layer. In this work, anthraquinone (AQ) is used as a modifier to boost the capacitance of OMCs. The modified materials (AQ/OMCs) can not only provide mesoporous channels facilitating rapid ion diffusion, but also generate extra pseudocapacitance improving specific capacitance greatly. As evidenced by electrochemical measurements, AQ/OMCs can exhibit specific capacitance as high as 346 F g−1 in 1 M H2SO4 electrolyte at the current density of 0.5 A g−1. Besides, the AQ/OMCs also possess excellent rate performance with capacitance retention ratio of up to 84.3% even at a very high current density of 30 A g−1. The outstanding capacitive performance of AQ/OMCs can be ascribed to the synergic effect between OMCs and AQ, in which ordered mesoporous channels facilitate rapid ion diffusion, and AQ generates large pseudocapacitance. In addition, asymmetric supercapacitor is assembled using AQ/OMCs and OMC as negative and positive electrode, respectively, which can deliver a very high energy density of 14.51 Wh kg−1 and excellent long-term cycle stability, retaining 96.3% of initial capacitance, after 10,000 cycles.