A Simple Strategy for Constructing Hierarchical Composite Electrodes of PPy-Posttreated 3D-Printed Carbon Aerogel with Ultrahigh Areal Capacitance over 8000 mF cm-2

A well-designed pore structure and optimized interface will improve specific capacitances of carbon-based supercapacitor electrodes significantly. Herein, a simple strategy is used to prepare the hierarchically porous 3D-printed carbon aerogel (CA) electrodes via combining direct ink writing, freezing drying, carbonization, and polypyrrole (PPy) posttreatment. The 3D-printed CA electrodes without PPy present a quasi-proportional increase in areal capacitance as thickness, achieving an extremely high areal capacitance of 6875 mF cm(-2) under a thickness of 2.2 mm. Additionally, PPy posttreated 3D-printed CA (PPy@CA) electrode has improved wettability and contact conductivity, which shows a further significant increase of areal capacitance to 8126 mF cm(-2). After 10 000 continuous cycles, the PPy@CA electrode exhibits an excellent cyclic stability similar to that of 3D-printed CA electrode by maintaining 91% of its original capacitance. This simple strategy may provide a novel insight to dramatically boost the energy storage properties of supercapacitor electrodes and their functionalization.

Automated summary

A well-designed 3D-printed carbon aerogel (CA) electrode, with optimized interface and pore structure, shows significantly improved areal capacitance under a thickness of 2.2 mm, and further enhancement in performance after polypyrrole (PPy) posttreatment. This simple strategy demonstrates potential for boosting energy storage properties of supercapacitor electrodes.