As a highly promising filtering component for next-generation lightweight and miniaturized electronic circuits, supercapacitors have pursued performance breakthroughs centered on the synergistic optimization of ultrafast frequency response and high areal capacitance. Reviewing the evolution of electrode design for filtering supercapacitors reveals a paradigm shift from mere compositional engineering toward an ordering-driven paradigm guided by rational microstructural design. In this review, carbon-based filtering electrodes are systematically categorized according to structural dimensionality and spatial organization, including two-dimensional planar architectures, three-dimensional randomly macroporous frameworks, and highly vertically aligned configurations, thereby elucidating a pivotal role of structural ordering in governing charge-transport kinetics. In particular, three-dimensional ordered grid electrodes constructed from carbon tubes as functional building units are identified as an effective strategy to resolve the intrinsic trade-off between capacitance density and frequency response.

From the construction of an integrated electron/ion transport networks, the systematic structural evolution clearly demonstrates that the continuous improvement of filtering supercapacitor performance does not arise merely from the unbounded enlargement of specific surface area, but rather from achieving an optimal balance between ion transport accessibility (i.e., low-tortuosity pathways) and interfacial charge-storage density (i.e., highly active surfaces). Such carbon-tube-based, ordered interconnected networks extend the performance limits in terms of capacitance and frequency response, and provide a robust and reproducible structural framework for ultrafast charge transport, thereby effectively propelling the transition of supercapacitors from conventional energy-storage devices toward high-frequency filtering applications.

Despite the remarkable potential of functional unit ordering strategies, some substantial challenges remain in translating this concept toward deeper theoretical understanding and practical implementation. From a theoretical perspective, there is an urgent need to establish a universal, quantitative descriptor system for assessing the "degree of ordering" in electrode architectures. Specifically, key geometric descriptors should include tortuosity (i.e., quantifying deviation of ion transport pathways from ideal straight channels), connectivity parameters (i.e., lateral junction density), orientation distributions (i.e., reflecting alignment along the current collector normal), and spatial uniformity metrics. The quantitative relationships can be established between structural parameters and kinetic metrics such as phase angle, cutoff frequency, and characteristic time constants via integrating these descriptors with electrochemical impedance spectroscopy and multiphysics simulations. Such a framework linking geometric descriptors to dynamic electrochemical responses will enable a transition from empirical optimization toward digitally guided electrode design.

In terms of transport mechanism analysis, it is particularly important to develop methods capable of decoupling the respective contributions of electronic conduction and ionic diffusion. For instance, an experimental strategy involving "fixed structure-variable conductivity" can be employed, whereby the crystallinity of the material is selectively tuned, while maintaining identical three-dimensional architectures and mass loading, thereby isolating the influence of electronic transport on the frequency response. In parallel, finite element simulations based on realistic structural models with independent variation of electronic conductivity (σ_e) and ionic diffusivity (D_ion) can be used to perform sensitivity analyses and establish causal relationships among structure, transport parameters, and electrochemical performance. These methods provide a critical theoretical guidance for the targeted optimization of ordered electrode architectures.

At the structural design level, future efforts should focus on maintaining kinetic advantages under thick-electrode and high-mass-loading conditions. To mitigate the transport limitations caused via increased loading, strategies such as constructing multidimensionally interconnected networks and optimizing hierarchical pore size distributions are required to ensure ultralow transport resistance for both electrons and ions, even in the deep regions of electrodes. This is essential for achieving simultaneous enhancement of areal capacitance and frequency response.

From an engineering perspective, the scalable fabrication of large-area, highly uniform ordered electrodes remains a key bottleneck in practical applications. Future developments should aim at synthesis strategies with improved generality and process tolerance to enable a smooth transition from centimeter-scale laboratory samples to industrial-scale electrode systems. In addition, some challenges relating to device packaging and circuit integration must be addressed, including minimizing the resistance at electrode/current collector interface, suppressing parasitic effects under high-frequency operation, and optimizing impedance characteristics at target frequencies (e.g., 120 Hz and above). Furthermore, the structural stability of three-dimensional porous architectures under long-term cycling, electro-thermal coupling, and mechanical deformation, as well as the reliability of multi-device integration, will critically determine their feasibility in applications.

Overall, building-unit ordering represents not merely a structural optimization strategy, but a unifying paradigm that bridges materials design, device performance, and application scenarios. With continued advancement of multiscale structural regulation capabilities, in-situ characterization techniques, and theoretical modeling tools, a research on filtering supercapacitor electrodes is expected to evolve from empirically driven exploration toward mechanism-informed and quantitatively guided design, ultimately enabling a broad application in highly integrated and miniaturized electronic systems.