the specific capacitances of supercapacitor electrodes measured by area or volume are the primary consideration for electrochemical energy storage within miniaturized footprint area. [11][12][13] Besides, for supercapacitor electrodes, the design of more doses of active materials means that there exists plenty of active sites available for reversible redox reactions. [14] As a result, it seems desirable to configure a supercapacitor electrode with a high mass loading (per unit area or volume) of active materials, such as a relatively dense distribution or a large thickness. However, such designs usually tend to cause the sluggish electron/ion diffusion, as well as the insufficient use of active materials, which instead limits the overall performance of supercapacitors. [15,16] Carbon aerogel (CA) is a type of hierarchically porous material ranging from micropores to macropores, which exhibits excellent application prospects in catalysis, adsorption, sensing, water evaporation, bone regeneration, electromagnetic shielding, and energy storage. [17][18][19][20][21][22][23][24] Especially, because of the excellent properties such as abundant porosity, ultrahigh specific surface area, good electrical conductivity, excellent infiltration, and good mass transfer ability, CA is considered as a promising electrode material in supercapacitors. [13,[25][26][27] Over the past few years, many efforts have been focused on modifying the pore size distribution of CA to further improve specific capacitance. The abundant micropores and small mesopores for CA are beneficial to the increase of specific capacitance due to a significant increase in specific surface area and active sites. [28] Interestingly, larger mesopores (20-50 nm) are detrimental to the specific capacitance due to the barrier effect for ion diffusion. [29,30] The precise control of sol-gel process was usually used to avoid these larger mesopores. [31] In addition, macropores, as well as micrometer-level or even sub-millimeter-level channels are also conducive to the improvement of specific capacitance, because of the unimpeded channels for electrolyte entry and replacement. [25,28,[32][33][34][35] However, excessive larger channels are unfavorable for their mechanical properties and loading amount of active materials. [16,23] Therefore, the hierarchical pores ranging from nanometer to sub-millimeter scale other than larger mesopores 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 improve...