Porous structural effect of carbon electrode formed through one-pot strategy on performance of ionic liquid-based supercapacitors

Abstract

Understanding of porous structural effect of carbon electrode on the electrochemical performance of ionic liquids-based supercapacitors is essential for the design of carbon-based electrode materials due to the large ion size and high viscosity induced sluggish ion diffusion rate. Herein, we report the electrochemical performance of supercapacitors using imidazolium-type ionic liquid as electrolyte and nitrogen-doped porous carbon with tunable porous structure as model electrodes synthesized by a one-pot multiscale silica-templated strategy through pH regulation. The results reveal that the porous structure has significant influence on the electrochemical performance of the accordingly assembled supercapacitors. Carbon-based electrode materials with interconnected macro-, meso- and micro-pores can significantly improve the energy density of the thus-assembled symmetric supercapacitor devices, delivering an energy density of 93 Wh·kg−1 at power density of 1.75 kW·kg−1. Benefiting from the interconnected multiscale pores, the assembled device can provide 48 Wh·kg−1 at a power density of 87 kW·kg−1 and lighten 20 white LEDs efficiently. Moreover, the assembled supercapacitor retains 88% of its initial capacitance after 10,000 continuous charge-discharge cycles at 10 A·g−1.