Sulfur‐Enriched Porphyrin‐Based Covalent Organic Frameworks as Redox‐Active Electrode for Aqueous Symmetric Supercapacitors

ABSTRACT

In this study, we report the design, synthesis and electrochemical evaluation of three porphyrin‐based covalent organic frameworks (COFs), TTP‐COF, BTP‐COF, and TP‐COF, integrating sulfur‐rich π‐conjugated aldehyde linkers (thieno[3,2‐b]thiophene, bisthiophene and thiophene) with C₄‐symmetric porphyrin knots via imine condensation. These frameworks exhibit enhanced electronic conductivity, efficient ion diffusion, and high structural stability. Among the tested materials, TTP‐COF exhibited superior electrochemical performance in the three‐electrode setup, delivering a high specific capacitance of 193.3 F g⁻¹. Furthermore, the symmetric supercapacitor (TTP‐COF // TTP‐COF) demonstrated a remarkable specific capacitance of 129.2 F g⁻¹, a high energy density of 35.2 Wh kg⁻¹, and outstanding cyclic stability, retaining its performance even after 25,000 charge–discharge cycles. Electrochemical studies revealed a dual charge storage mechanism involving both electric double‐layer capacitance and pseudocapacitance, attributed to redox‐active porphyrin units and sulfur‐containing linkers. Nyquist analysis confirmed the lowest charge transfer resistance (R _ct = 0.18 Ω) for TTP‐COF, highlighting its efficient charge transport characteristics. A symmetric supercapacitor device based on TTP‐COF successfully powered white and red LEDs, validating its real‐world applicability. This work underscores the potential of rationally engineered porphyrin‐thiophene COFs as advanced materials for next‐generation supercapacitor technologies.

The illustration depicts the sulfur‐enriched TTP‐COF, integrating redox‐active thieno[3,2‐b]thiophene linkers and porphyrin units for efficient charge transport and extended π‐conjugation. The framework exhibits excellent electrochemical performance with a specific capacitance of 193.3 F g⁻¹, 92.3% capacitance retention after 25 000 cycles, and successfully powers LEDs, highlighting its potential as a high‐performance electrode for next‐generation supercapacitors.

1. Introduction

With the global population projected to surpass 9 billion by 2050, the demand for sustainable resources is set to escalate dramatically. Among the many global issues ranging from water scarcity to climate change, energy stands as the foundational challenge [1]. The growing energy demands call for clean, efficient, and sustainable solutions alongside advanced technologies for energy conversion and storage [2]. A viable approach to balancing fluctuations in energy supply and demand involves electrochemical storage systems developed with sustainable, high‐efficiency materials that minimize environmental impact. Electrochemical energy storage systems operate via distinct mechanisms: batteries store energy through charge‐transfer within electrodes [3], fuel cells rely on externally supplied reactants, redox‐flow cells use circulating redox species, while supercapacitors store energy through electrostatic charge at the electrode‐electrolyte interface, enabling significantly higher capacitance values [4, 5]. It offers unique pathways to enhance power [6]. Electrochemical supercapacitors (ECs) have captured growing scientific attention for their ability to deliver rapid power bursts, endure extensive charge discharge cycles, and seamlessly bridge the divide between high‐power capacitors and high‐energy storage technologies [7, 8]. ECs can be further categorized based on their underlying charge storage mechanisms and the nature of the active electrode materials employed [9]. According to their charge storage mechanism, ECs are categorized into electrochemical double‐layer capacitors (EDLCs), pseudocapacitors and hybrid capacitors. EDLCs use carbon‐based [4, 10, 11, 12, 13, 14] materials for electrostatic charge storage, while pseudocapacitors employ redox‐active materials like metal oxides [15, 16, 17] or conducting polymers [18]. However, as the functional backbone of supercapacitors, electrodes have been the focus of intensive material engineering ranging from carbides, nitrides and carbonitrides of transition metals, referred to as MXenes [19, 20] to organic systems, to maximize charge storage capability and enhance device efficiency [21].

In this context, covalent organic frameworks (COFs), with their crystalline order, tunable porosity, and versatile chemical functionality, offer immense potential in energy storage and conversion [21, 22, 23, 24]. Unlike conventional carbon‐based or metal oxide electrodes, COFs offer modular architecture, high surface area, uniform porosity and customizable redox functionality enabling enhanced charge storage, faster ion transport and improved cycling stability as electrode materials for supercapacitors [25, 26]. The highly ordered and tunable pore architecture of COFs facilitates efficient ion diffusion through well‐defined channels, thereby enhancing charge transport and overall electrochemical performance in supercapacitor systems [23, 27]. Strategic functionalization of COF frameworks with redox‐active moieties can effectively transition their charge storage behavior from purely electrostatic to faradaic, unlocking higher capacitance and improved energy density in pseudocapacitive applications [28, 29, 30]. However, the inherently low electrical conductivity of COFs in an electrolyte environment poses a significant challenge to their application as efficient electrode materials in supercapacitors. To address the inherent limitation of low electrical conductivity in COFs, the strategic incorporation of π‐conjugated and redox‐active moieties such as porphyrins [31], phthalocyanines [32], pyrenes [33], and thiophenes [34] has proven highly effective in enhancing charge transport throughout the framework. Among these, porphyrin units stand out as exceptionally versatile building blocks for energy storage applications. Exhibiting strong absorption in the near‐UV‐visible region, the macrocycle's inherent thermal robustness and modifiable core architecture endow it with notable structural and electronic flexibility [35]. Their planar geometry and extensively π‐conjugated macrocyclic structure [36] make them ideal monomeric components for the construction of COFs. The precise topology of COFs [37, 38, 39], particularly those adopting square‐connected architectures, plays a decisive role in dictating their porosity, crystallinity, and overall functional performance [40, 41, 42]. Porphyrin‐based COFs exploits the square‐planar geometry of porphyrin cores as structural nodes, exhibit superior structural order and design modularity compared to frameworks constructed from conventional organic linkers. Their architectural advantage facilitates the fine‐tuning of electronic, photonic, and catalytic properties, making porphyrin‐based COFs [43, 44, 45] highly promising for advanced functional applications. The rational selection of functionalized porphyrin monomers, in combination with appropriately designed linker units, enables the construction of highly ordered COFs featuring robust covalent bonding and well‐defined topologies [46]. COFs are formed via slightly reversible condensation reactions between organic linkers. This dynamic bonding allows for error correction during synthesis, leading to crystalline structures with high thermal stability, unlike amorphous polymers [47]. The earliest COFs were synthesized through the co‐condensation of boronic acids with catechols to form boronic esters, or via the self‐condensation of boronic esters into a boroxine‐linked framework [48]. Addressing the hydrolytic instability associated with boroxine and boronic ester linkages, this work adopts an imine‐based coupling strategy that integrates planar C4‐symmetric porphyrin units as knots with C₂‐sulfur‐containing linkers, leading to the formation of COFs. Imine‐linked COFs have garnered significant interest as robust and versatile scaffolds attributed to their remarkable chemical stability and the synthetic ease of their formation [49, 50, 51, 52, 53]. Alongside electrode materials, the choice of electrolyte is equally critical in determining the performance of supercapacitors, as it governs ion transport and the accessible operating voltage window. Organic and ionic liquid electrolytes can extend potential ranges but face limitations such as high cost, toxicity, and low conductivity, whereas aqueous electrolytes are inexpensive, safe, and highly conductive, though generally restricted to ∼1.0 V in acidic or alkaline media. Interestingly, neutral aqueous electrolytes have recently enabled voltage windows up to ∼2.2 V by suppressing hydrogen and oxygen evolution [54, 55, 56].

This study presents the solvothermal synthesis and detailed characterization of porphyrin‐based COFs, incorporating thiophene, bithiophene, and thienothiophene‐derived aldehyde linkers to explore the impact of sulfur‐rich π‐conjugated linkers on the structural and electronic properties of the resulting frameworks. The incorporation of sulfur atoms using the thiophene units enhances charge carrier mobility as these units are known to contribute to some of the highest charge carrier mobilities observed in organic materials [57], while the planar porphyrin architecture contributes to structural integrity and electronic richness together resulting in chemically robust COFs as superior electrode materials for supercapacitors. The resulting architecture facilitates long‐range π‐π stacking and effective orbital overlap, establishing a continuous pathway for electron transport and thereby imparting conductive characteristics to the material. Collectively, this approach presents a promising pathway for the development of advanced COF‐based materials tailored for optoelectronic and energy storage applications.

2. Experimental Section

2.1. Chemicals and Materials

All reagents and solvents were of analytical grade and used without further purification unless otherwise specified. Propionic acid, 4‐nitrobenzaldehyde, acetic anhydride, pyrrole, pyridine, hydrochloric acid, tin(II) chloride dihydrate (SnCl₂•2H₂O) and ammonia solution, were purchased from Sigma‐Aldrich and Merck. Aldehyde linkers used in COF construction, namely thieno[3,2‐b]thiophene‐2,5‐dicarbaldehyde, [2,2'‐bithiophene]‐5,5'‐dicarbaldehyde, and 2,5‐thiophenedicarboxaldehyde were obtained from BLD Pharma, India, and used as received. Absolute ethanol, mesitylene, Tetrahydrofuran (THF), acetone, glacial acetic acid, and 1,4‐dioxane were procured from Merck.

2.2. Instrumentation

Powder X‐ray diffraction (P‐XRD) patterns were recorded using a Bruker D8 Advance diffractometer equipped with a 2.2 kW copper anode X‐ray source (Cu Kα radiation), operated at 40 kV and 40 mA. Data acquisition was carried out using a high‐resolution LINXEYE XE detector, with a fine angular resolution of 0.0001° and reproducibility within ± 0.0001°, across a 2θ scan range of 0°–120°, enabling comprehensive structural assessment. Fourier‐transform infrared (FT‐IR) spectra were obtained using a Bruker spectrophotometer in 4000–500 cm⁻¹ range, with background correction applied. Thermogravimetric analysis (TGA) was performed on an EXSTAR TG/DTA6300 instrument to assess the thermal stability. Morphological and elemental analyses were conducted using a Thermo Fisher Apreo S Low Vacuum field‐emission scanning electron microscope (FE‐SEM) integrated with energy‐dispersive X‐ray spectroscopy (EDS). High‐resolution transmission electron microscopy (HR‐TEM) studies were carried out on a Thermo Fisher TALOS F200X microscope operating at 200 kV, featuring an X‐FEG electron source with an energy spread of 0.8 eV. Crystallographic features were examined using selected area electron diffraction (SAED). For TEM sample preparation, the materials were ultrasonically dispersed in ethanol (15–20 min), and a drop of the suspension was deposited on a carbon‐coated copper grid (G200, 3.05 mm diameter). Elemental composition and spatial distribution were confirmed using EDS mapping with a resolution of 136 eV. X‐ray photoelectron spectroscopy (XPS) was conducted on a PHI 5000 VersaProbe III spectrometer (ULVAC‐PHI, Japan) to determine the chemical states and surface composition of the samples. Electrochemical performance was evaluated using a Metrohm Autolab M204 potentiostat/galvanostat system operated via NOVA 2.0 software. Measurements included cyclic voltammetry (CV), galvanostatic charge‐discharge (GCD), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). Gas sorption studies were performed on a Quantachrome Autosorb iQ Station 1 analyzer. Nitrogen adsorption‐desorption isotherms were recorded at 77.35 K and 1 bar, following degassing of the samples at 120 °C for 8 h under vacuum. BET and Langmuir surface areas were determined using standard protocols. Pore size distribution was calculated using density functional theory (DFT) models in QuadraWin software, employing the QSDFT method with helium void volume corrections and thermal transpiration adjustments applied during analysis.

2.3. Synthesis

The porphyrin precursor tetra(p‐aminophenyl)porphyrin (TAPP) was prepared by the method described in the literature [58] as described in Section 1 in Supporting Information. Both tetranitrophenylporphyrin (TNPP) and TAPP were well characterized by UV‐Visible spectroscopy, MALDI‐TOF‐MS and ¹H‐NMR spectrum (Figures S1–S5). Aminophenyl‐based COFs featuring diverse π‐conjugated thiophene linkers were synthesized via a modified solvothermal method. Specifically, thieno[3,2‐b]thiophene‐2, 5‐dicarbaldehyde, [2,2'‐bithiophene]‐5,5'‐dicarbaldehyde, and 2,5‐thiophenedicarboxaldehyde were employed as dialdehyde linkers to obtain TTP‐COF, BTP‐COF, and TP‐COF, respectively. As illustrated in Scheme 1, the synthesis involved combining TAPP (0.02 mmol) and the corresponding dialdehyde linker (0.04 mmol) in a pyrex tube, along with 0.5 mL of absolute ethanol, 0.5 mL of mesitylene, and 0.1 mL of freshly prepared 6 M aqueous acetic acid. The mixture was subjected to three consecutive freeze‐pump‐thaw cycles to eliminate dissolved gases, followed by flame‐sealing under vacuum.

SCHEME 1.

Representation of the solvothermal synthesis COFs via imine condensation between tetra(p‐aminophenyl)porphyrin (TAPP) and the π‐conjugated dialdehyde linkers and their energy storage aspects.

The sealed tube was heated at 120°C in a silicon oil bath for 72 h. After naturally cooling to room temperature, a purple precipitate was collected by centrifugation. The crude product was washed thoroughly with 1,4‐dioxane, tetrahydrofuran (THF), and acetone to remove unreacted monomers and oligomers. Finally, the purified material was dried under vacuum overnight, yielding the desired COF as a fine purple powder. The typical isolated yield was approximately 15 mg per batch.

2.4. Fabrication of Electrodes

To fabricate the electrodes, a homogeneous slurry was prepared by mixing 70 mg of the synthesized COF with 10 mg of activated carbon and 10 mg of poly(vinylidene difluoride) (PVDF) in 1 mL of N‐methyl‐2‐pyrrolidone (NMP), maintaining a weight ratio of 8:1:1. For the three‐electrode configuration, approximately 1 mg cm⁻² of the slurry was uniformly applied onto 1 cm × 1 cm graphite sheets (thickness: 0.2 mm), which served as the working electrodes. A platinum wire and an Ag/AgCl (3 M KCl) electrode were employed as the counter and reference electrodes, respectively. The coated electrodes were dried under vacuum at 60 °C overnight to remove residual solvent. For the symmetric supercapacitor (SSC) configuration, identical slurry‐coated electrodes were prepared on 1 cm × 1.5 cm graphite sheets (thickness: 0.5 mm) and assembled using Whatman filter paper as a separator. The total mass of active material on both electrodes was ∼2.5 mg. Prior to electrochemical testing, both configurations were preconditioned by running 50 cycles of CV to ensure system stability and proper electrode activation.

3. Result and Discussion

Porphyrin‐based COFs were synthesized via a solvothermal approach using three different thiophene‐derived aldehydic linkers. The formation of these frameworks was verified by attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). The characteristic imine (C═N) linkages in TTP‐COF, BTP‐COF and TP‐COF were clearly evidenced by these complementary spectroscopic analyses, confirming the successful construction of the targeted COFs. The FT‐IR spectra of the aldehydic linkers, viz., TT‐L (Thieno[3,2‐b]thiophene‐2,5‐dicarboxaldehyde), BT‐L (2,2′‐Bithiophene‐5,5′‐dicarboxaldehyde), and T‐L (2,5‐Thiophenedicarboxaldehyde), exhibit the characteristic vibrations of aldehyde functional groups as shown in Figure 1a. A prominent absorption band observed in the region of ∼1660 cm⁻¹ is attributed to the C═O stretching of the terminal ‐CHO groups, confirming their presence in all three linkers. In addition, weak absorptions in the range of ∼2720–2850 cm⁻¹ correspond to the aldehydic C─H stretching, while aromatic C‐H stretching vibrations appear near ∼3000 cm⁻¹. The FT‐IR spectrum of TAPP shows characteristic N‐H stretching bands in the region ∼3439–3354 cm⁻¹ (‐NH₂) and 3297 cm⁻¹ (pyrrolic ‐NH) [59] as represented in Figure 1b. These absorptions gradually disappear upon COF formation, confirming the consumption of the amine groups during the condensation reaction. In the spectra of TTP‐COF, BTP‐COF and TP‐COF, a distinct band around ∼1620 cm⁻¹ appears, corresponding to the C═N stretching vibration of the newly formed imine linkages (Figure 1b). This serves as direct evidence for the successful Schiff‐base condensation between TAPP and the respective linkers (TT, BT, and T). Moreover, the absence of strong aldehyde C═O stretching vibrations in all COFs further confirms the complete reaction of aldehydic groups with the amino functionalities of TAPP. Raman spectroscopy further supported this observation, displaying C═N stretching bands in the range of 1610–1640 cm⁻¹. The Raman spectra of TTP‐COF, BTP‐COF and TP‐COF exhibit distinct bands in the 1300–1600 cm⁻¹ region, which are characteristic of the porphyrin macrocycle. Prominent peaks around ∼1350 cm⁻¹ correspond to the C–N stretching vibrations of the pyrrole rings, while features in the 1500–1550 cm⁻¹ region are associated with C═C stretching and skeletal vibrations of the porphyrin core [60, 61]. These vibrations are retained across all three COFs, indicating that the porphyrin unit remains structurally intact after framework formation (Figure 1c). ¹³C cross‐polarized magic angle spinning (CP‐MAS) solid‐state NMR spectroscopy reveals the formation of a fundamental imine linkage. It provided additional confirmation, showing a distinct resonance at δ ≈ 159 ppm, attributed to the imine carbon for all synthesized COFs (Figures S6–S8).

FIGURE 1.

Representing of FT‐IR spectra of (a) COFs w.r.t TAPP and (b) Aldehyde linker units, (c) Raman spectra of the COFs, Solid‐state UV‐vis diffuse reflectance spectra of (d) TTP‐COF, (e) BTP‐COF, and (f) TP‐COF, P‐XRD patterns with simulated spectra (g) TTP‐COF, (h) BTP‐COF and (i) TP‐COF (Insets show magnified views of the low‐angle diffraction regions for clarity).

The absence of signals corresponding to unreacted aldehyde and amine groups in all three COFs affirms the high chemical purity and successful Schiff base condensation leading to the formation of the targeted frameworks. Solid‐state UV‐Vis diffuse reflectance spectra (DRS) of the COF samples were recorded using a UV‐Vis spectrophotometer equipped with an integrating sphere in diffuse reflectance mode. Porphyrins are recognized for their active absorption in the visible spectrum, contemporary endeavours focus on extending their light‐absorbing capabilities, particularly into the near‐infrared (NIR) region [62]. The absorption spectra of synthesised COFs exhibit distinct absorption features characteristic of porphyrin‐based chromophores, including well‐resolved Soret and Q‐bands. The Soret bands, arising from π–π* transitions within the porphyrin core [63], appear prominently at 483 nm for both TTP‐COF and TP‐COF and at 473 nm for BTP‐COF, indicating subtle variations in electronic environments due to different thiophene‐based linkers. The Q‐bands, which are indicative of lower‐energy electronic transitions and sensitive to the extent of π‐conjugation, appear as multiple absorptions in the 500–700 nm region [64]. For TTP‐COF (Figure 1d), Q‐band maxima are observed at 529, 574, and 663 nm, for BTP‐COF at 524, 565, and 655 nm(Figure 1e), and for TP‐COF at 531, 573, and 661 nm (Figure 1f). The slight red shift in Q‐band positions for TTP‐COF and TP‐COF compared to BTP‐COF suggests enhanced π‐delocalization and stronger intermolecular interactions in these frameworks. These spectral features confirm the successful incorporation of porphyrin units into the COF backbones while retaining their optoelectronic integrity. Imine‐linked COFs are recognized for their enhanced chemical stability compared to boroxine and boronate ester‐linked frameworks; however, they often exhibit relatively lower crystallinity and moderate accessible porosity [65, 66, 67]. In the present case, the presence of distinct diffraction peaks in the low‐angle region indicates periodic structural ordering within the framework. For TTP‐COF (Figure 1g), a prominent diffraction peak was observed at 2θ = 2.41°, BTP‐COF showed a low‐angle peak at 2θ = 2.24° (Figure 1h), and for TP‐COF at 2θ = 2.16° (Figure 1i), consistent with a periodic structure in crystalline frameworks, and these low‐angle peaks closely align with the simulated pattern, respectively. The broad peaks around 20° and 26° correspond to layered π‐π stacking among the 2D network [59]. The interlayer interactions play a crucial role in directing the formation of layered stacking arrangements. In imine‐linked systems, the inherent polarity of the C═N linkage can introduce interlayer electrostatic interactions and stacking disorder, which may limit long‐range crystallinity while still preserving ordered domains within the framework [68]. Nevertheless, the presence of lattice fringes in HRTEM images and a distinct SAED pattern further supports the formation of ordered domains within the frameworks, corroborating the P‐XRD observations. XPS was employed to analyze the elemental composition of the synthesized COFs and to elucidate the interfacial interactions of their surface species. As depicted in Figure 2a, the XPS survey spectra show distinct peaks corresponding to the binding energies of C 1s, N 1s, and S 2p observed at 284, 398.5, and 162.5 eV, respectively. Figure 2a′ presents an expanded view of the S 2p region from the survey spectra for the three COFs. The lower peak intensity of S 2p peak for TP‐COF highlights its reduced sulfur content compared to BTP‐COF and TTP‐COF. The elemental composition, highlighting their relative atomic percentages in the respective COFs, is shown in Figure 2b. The high‐resolution XPS spectra of C, N, and S, in TBP‐COF (Figure 2c–e), TTP‐COF (Figure 2f–h), and TP‐COF (Figure 2i–k) are deconvoluted to elucidate the detailed bonding environments of these elements within the extended frameworks. The high‐resolution C 1s spectra of TTP‐COF and BTP‐COF can be deconvoluted into three Gaussian‐Lorentzian curves [69], corresponding to sp² C─C/C═C (284 eV), C═C (∼28.5 eV), and C–N/C–S (∼287 eV) bonds [70]. While the C 1s spectra of TP‐COF can be resolved into four distinct components, assigned to C–C/C═C, C–N, C–S, and C═N linkages. The N 1s spectra of all three COFs show three peaks around ∼ 398, 399, and 400 eV, which further confirm the coexistence of pyridinic, amino, and pyrrolic nitrogen species [70, 71]. The consistent presence of these peaks across all COFs highlights the structural integrity of porphyrin units, while slight shifts in binding energies suggest subtle differences in electronic environments depending on the linker. The S 2p spectra, with well‐defined peaks, S 2p_3/2 at ∼163.8 eV and S 2p_1/2 at ∼165 eV, establish the presence of sulfur in the form of C‐S‐C linkages. The S 2p peaks appear a little weaker in TP‐COF at a binding energy of 163.7 and 164.9 eV, confirming sulfur incorporation through C─S bonding motifs [72]. The distinct XPS features observed for TP‐COF can be attributed to the distinct chemical environment due to the presence of only one thiophene ring. The high‐resolution spectra provide clear evidence for the incorporation of carbon, nitrogen, and sulfur into the core framework, thereby validating the effective coordination of sulfur‐containing linker units with monomeric porphyrin units. The morphological and structural features of the synthesized COFs were comprehensively characterized using FE‐SEM and TEM. FE‐SEM images, as depicted in Figure 3i–iii demonstrate distinct morphologies for each COF. TTP‐COF shows aggregated flake‐like structures, BTP‐COF exhibits uniform rod‐shaped crystallites, and TP‐COF demonstrations evenly distributed spherical particles. The average particle sizes, estimated from image analysis, were ∼ 591 nm for TTP‐COF, 237 nm for BTP‐COF, and 169 nm for TP‐COF. The progressive reduction in particle size across the series may be attributed to variations in linker structure and crystallization behavior. These differences arise from the structural variations in the π‐conjugated thiophene linkers used during synthesis. TEM imaging provided further insight into the internal architecture, revealing well‐developed crystalline domains and highlighting the intrinsic porous nature of the frameworks (Figure 3a–c). High‐resolution transmission electron microscopy (HRTEM) images reveal well‐resolved lattice fringes in all three COFs, indicative of their crystalline nature. The degree of crystallinity was further evaluated through fast Fourier transform (FFT) analyses (Figure 3a′–c′) and SAED pattern (Figure 3a″–c″). SAED reveals that the intense pattern of bright spots is indicative of the highly crystalline nature of the synthesized material. Each spot corresponds to specific crystallographic planes of the material and their respective lattice spacing. The symmetry and arrangement of the spots reflect the crystal symmetry. Among the three samples, TTP‐COF and BTP‐COF exhibited distinct and sharp diffraction patterns, indicative of a high degree of structural order and long‐range periodicity. In contrast, TP‐COF displayed relatively diffuse diffraction features, suggesting a lower degree of crystallinity. Energy‐dispersive X‐ray spectroscopy (EDS) and elemental mapping (Figure 3a‴–c‴) demonstrate uniform distribution of carbon (C), nitrogen (N), and sulfur (S) in each COF. Also, the elemental composition from EDS measurements is provided in Figure S9. The overlayed “Mix” images confirm homogeneous elemental integration throughout the frameworks, further verifying the successful formation of imine‐linked COFs based on porphyrin and thiophene‐based building blocks. These results collectively confirm the successful formation of imine‐linked COF architectures with tunable morphology and crystallinity influenced by the nature of the incorporated π‐conjugated linker. The textural properties of TTP‐COF, BTP‐COF, and TP‐COF were evaluated through nitrogen adsorption‐desorption isotherms recorded at 77 K. The specific surface areas, calculated using the Brunauer–Emmett–Teller (BET) method, suggest a porous nature for all COF samples as represented in Figure S10, SI. Nitrogen adsorption‐desorption isotherms recorded at 77 K for TTP‐COF, BTP‐COF, and TP‐COF revealed typical type IV profiles with hysteresis loops in the relative pressure range of P/P₀ = 0.4–0.99, indicative of mesoporous structures. An increase in nitrogen uptake at higher pressures (P/P₀> 0.9) confirms capillary condensation in mesopores and interparticle voids. However, notable differences in adsorption profiles reflect various pore architecture. The BET surface areas were calculated as 42.6 m² g⁻¹ for TTP‐COF, 38.5 m² g⁻¹ for BTP‐COF, and 42.6 m² g⁻¹ for TP‐COF. These values, though moderate, reflect the influence of linker geometry and packing on pore accessibility. Slight variations in surface area can be attributed to differences in linker rigidity and framework crystallinity. Such moderate surface areas are often observed in π‐conjugated porphyrin‐based COFs [68, 73]. All COFs showed substantial nitrogen uptake at high relative pressures, with TTP‐COF reaching 202.3 cm³ g⁻¹, BTP‐COF 200 cm³ g^−1, and TP‐COF 128.6 cm³ g⁻¹, suggesting hierarchical porosity.

FIGURE 2.

XPS Analysis, (a) Survey spectra of BTP‐COF, TTP‐COF, and TP‐COF, (a′) magnified S 2p spectra for three COFs, (b) Elemental composition (Atomic %) of the three COFs, Deconvoluted high‐resolution C 1s, N 1s, and S 2p spectra for BTP‐COF (c–e), TTP‐COF (f–h), and TP‐COF (i–k).

FIGURE 3.

FESEM images showing distinct surface morphologies of COFs (i–iii), TEM images (a–c), HRTEM images showing well‐defined lattice fringes (a′–c′), Corresponding selected area electron diffraction (SAED) patterns (a″–c″), Elemental mapping images, showing uniform distribution of carbon (C), nitrogen (N), and sulfur (S) in all three COFs (a‴–c‴).

Furthermore, the pore size distributions derived using the non‐local density functional theory (NLDFT) model were analyzed using the adsorption branch to obtain a more reliable description of the pore architecture Figure S10. TTP‐COF exhibits a predominantly microporous structure with a sharp peak centered at 1.5–1.7 nm, indicating a compact, well‐ordered framework. In contrast, BTP‐COF shows a mesopore‐dominated distribution with a peak at 3.79 nm, while TP‐COF displays a broad pore size distribution. Overall, all three COFs exhibit hierarchical porosity with significant interparticle voids. The moderate surface areas observed are attributed to differences in pore accessibility and structural organization rather than framework collapse, with TTP‐COF showing a more optimized pore architecture for electrochemical applications. Although the surface areas are not exceptionally high, the hierarchical pore structures, accessible mesoporosity, and sulfur‐rich π‐conjugated linkers support their applicability in electrochemical energy storage. These structural attributes enhance ion diffusion and provide accessible redox‐active sites, making them promising candidates for supercapacitor electrodes. The thermal stability of these COFs was investigated by thermogravimetric analysis (TGA) under a nitrogen atmosphere (Figure S11). All three COFs exhibit multistep weight loss shapes. An initial minor weight loss below ∼150°C is attributed to the removal of physisorbed moisture and residual solvent molecules. Beyond this, the frameworks display excellent thermal robustness, retaining a significant portion of their weight up to ∼350°C–400°C, which is indicative of the high stability of the imine‐linked porous networks. Density functional theory (DFT) calculations were performed at the B3LYP/6‐31G* level using the Gaussian 16 program to understand the role of sulfur‐based linker units in modulating the electronic properties of the COFs. The frontier molecular orbital analysis (Figure S12 SI) shows that the HOMO is predominantly localized on the porphyrin core, while the LUMO is mainly distributed over the sulfur‐containing linker units, indicating an intrinsic donor‐acceptor architecture. Notably, the extent of electron delocalization increases from TP‐COF to BTP‐COF and TTP‐COF due to the incorporation of thiophene‐based linkers, resulting in enhanced conjugation across the framework. The calculated HOMO‐LUMO gaps decrease progressively from 2.39 eV for TP‐COF to 2.33 eV for BTP‐COF, with TTP‐COF exhibiting the lowest band gap of 2.28 eV amongst the three COFs. This reduction is primarily attributed to the stabilization of the LUMO level induced by sulfur‐rich conjugation, while the HOMO remains relatively unchanged. The narrower band gap calculated in TTP‐COF facilitates improved charge transport and lowers the energy barrier for electron transfer, thereby enhancing redox activity. The I‐V characteristics were obtained using four‐probe DC conductivity measurements (Figure S13). The curves exhibit nearly quasi‐linear and symmetric behavior, indicating ohmic‐type charge transport, although the overall current response is relatively low. Among the samples, TTP‐COF shows a relatively higher current under identical applied bias, suggesting improved charge transport.

3.1. Electrochemical Study

The electrochemical behavior of the synthesized COFs was examined using a standard three‐electrode system in an aqueous solution of 0.5 M K₂SO₄. To begin, linear sweep voltammetry (LSV) was used to identify the electrochemical stability window (ESPW) for each COF material. The LSV results showed that the ESPW for the COFs extended up to 1.8 V, ranging from –1.0 V to +0.8 V (Figure 4a). To further investigate the usable voltage range for each COFs, cyclic voltammetry (CV) was carried out within specific potential windows at various scan rates from 5 to 100 mV s⁻¹. For TTP‐COF, the CV was performed from –0.7 to 0.7 V, while BTP‐COF and TP‐COF were tested within –0.7–0.6 and –0.8–0.5 V, respectively (Figure S14 and Figure 4b). These measurements confirmed that TTP‐COF has a stable operating voltage of 1.4 V, whereas both BTP‐COF and TP‐COF have operational windows of 1.3 V. When the applied potential exceeded these ranges, gas‐evolving side reactions such as the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) began to occur, indicating the limits of safe operation. Additionally, the CV curves showed a small hump called pseudocapacitive peaks around +0.36, +0.26, and +0.20 V in the anodic potentials for TTP‐COF, BTP‐COF, and TP‐COF, respectively. Similarly, peaks appeared in the cathodic potentials at –0.33, –0.31, and –0.20 V (Figure 4b). These features were observed at a scan rate of 10 mV s⁻¹ and suggest the presence of minor redox activities, which contribute to the charge storage behavior of the materials. The presence of these peaks suggests that pseudocapacitive behavior may be occurring in the material. This behavior is likely associated with redox reactions involving the porphyrin units and the sulfur‐containing linkers present in the structure. During these reactions, nascent hydrogen (a highly reactive form of hydrogen) may be produced. This hydrogen can either be generated directly during the electrochemical process or become trapped within the porous structure of the material at certain active sites. These processes contribute to the overall charge storage behavior of the material.

FIGURE 4.

LSV measurements of TTP‐COF, BTP‐COF, and TP‐COF at 5 mV s⁻¹ (a), their CV at 10 mV s⁻¹ (b), GCD at 0.7 A g⁻¹ current density in 0.5 M K₂SO₄ (c), Bar plot showed gravimetric specific capacitance at 0.7 A g⁻¹ (d), Bar plot showed areal capacitance (F cm⁻²) (e), Ragone plot showing specific capacitance at 0.7 to 10 A g⁻¹) (f).

The small redox humps observed in the CV curves originate from surface‐confined partially Faradaic reactions occurring at the electroactive sites within the porphyrin‐based COF frameworks. As shown in the structure, the frameworks contain porphyrin macrocycles, imine linkages (–C═N–) [24, 74], and sulfur‐containing heterocyclic linkers, which provide multiple redox‐active centers (Scheme S1). The porphyrin macrocycle acts as the primary redox‐active unit. During electrochemical polarization, the conjugated porphyrin ring undergoes reversible electron‐transfer reactions, forming nascent hydrogen. In the neutral K₂SO₄ electrolyte, charge neutrality during this redox transition is maintained mainly by adsorption/desorption of K⁺ ions at the nitrogen‐rich cavity of the porphyrin ring and nearby heteroatom sites. This reversible interaction between the framework and electrolyte ions generates the anodic and cathodic peaks observed in the CV curves. The imine linkages (–C═N–) in the framework can also contribute to pseudocapacitive behavior. These electron‐deficient sites participate in reversible surface redox reactions accompanied by ion adsorption. Additionally, the sulfur‐containing linker units enhance pseudocapacitive behavior due to the polarizable sulfur atoms that facilitate electron delocalization across the conjugated framework. These heteroatoms improve charge transfer and provide additional adsorption sites for electrolyte ions. The slight shift in peak potentials among TTP‐COF, BTP‐COF and TP‐COF can be attributed to differences in linker structure, conjugation length and electron‐donating ability of the sulfur‐containing units, which modulate the electronic environment of the porphyrin core and thus influence the redox potential. The specific capacitance of the materials was determined by performing galvanostatic charge‐discharge (GCD) tests at different current densities 0.7, 1, 3, 5, 7, and 10 A g^−1, within appropriate potential windows of 1.4 V for TTP‐COF and 1.3 V for both BTP‐COF and TP‐COF (Figures. 4c, S14). The charge‐discharge curves for TTP‐COF, BTP‐COF, and TP‐COF appeared nearly triangular in shape, which is typical of ideal capacitive behavior. At a current density of 0.7 A g⁻¹, the specific capacitance values were found to be 193.3 F g⁻¹ for TTP‐COF, 155.5 F g⁻¹ for BTP‐COF, and 85.6 F g⁻¹ for TP‐COF. Additionally, the areal capacitance of these materials was calculated to be 0.193, 0.156, and 0.064 mF cm⁻², respectively (Figure 4d,e). The specific capacitance values of TTP‐COF, BTP‐COF, and TP‐COF were measured at various current densities, including 0.7, 1, 3, 5, 7, and 10 A g⁻¹, to evaluate their rate capability. As shown in Figure 4f, all three materials demonstrated good performance across the tested range. Among them, TTP‐COF exhibited the highest specific capacitance. This superior performance is primarily due to the structural advantages provided by the combination of porphyrin units and Thieno[3,2‐b]thiophene‐2,5‐dicarbaldehyde in its framework. These components offer a larger number of electroactive sites that readily interact with electrolyte ions. Additionally, the well‐organized porous structure of TTP‐COF promotes efficient ion transport and diffusion throughout the material, which collectively enhances its charge storage ability at different current densities.

The CV curves obtained in 0.5 M K₂SO₄ at varied scan rates from 10 to 25 mV s⁻¹ to gain a deeper understanding of the energy storage mechanism in the electrode materials, TTP‐COF, BTP‐COF, and TP‐COF (Figure 5a–c). The corresponding CV curve shows a higher current with an increasing scan rate, indicating that the charge transfer resistance of the TTP‐COF, BTP‐COF, and TP‐COF electrode surface is found to be lower. However, a slight shift in the peak position was observed in both directions, demonstrating electrode polarization. To better understand the charge storage behavior of TTP‐COF, BTP‐COF, and TP‐COF, Dunn's method was employed, using the equation i = k₁v + k₂v^1/2, where i is the current and v is the scan rate. This method helps to differentiate between capacitive (surface‐controlled) and diffusion‐controlled (pseudocapacitive) contributions to the overall current. The results were illustrated through current‐voltage (CV) measurement and corresponding bar graphs (Figure 5aʹ–cʹ and (aʺ–cʺ), which demonstrate the percentage of each contribution at varying scan rates. It was observed that as the scan rate increased from 10 to 25 mV s⁻¹, the capacitive contribution also increased slightly for all three materials. This is because, at lower scan rates, the ions have enough time to diffuse into the porous structure and reach the redox‐active sites within the interlayer spaces. However, at higher scan rates, the time available for ion diffusion is limited, which restricts ion access to deeper pores, thereby favoring capacitive behavior over diffusion‐limited processes. Specifically, at a scan rate of 10 mV s⁻¹, the capacitive (EDLC) contributions to the total charge storage for TTP‐COF, BTP‐COF, and TP‐COF were found to be approximately 53.9%, 50.4% and 58.8%, respectively. The remaining portions 46.1%, 49.6%, and 41.2%, were attributed to diffusion‐controlled (pseudocapacitive) mechanisms (Figure 5aʹʺ–cʹʺ). These findings highlight the dual electrochemical storage behavior of these COF‐based materials, with a significant portion arising from both surface adsorption and faradaic redox processes.

FIGURE 5.

CV curves at 10–25 mV s⁻¹ (a–c), the Peak current (i _p)/((𝜐)^1/2, scan rate)^1/2 versus (𝜐)^1/2 (aʹ–cʹ), CV curves of MWCNT@PTZ‐COP for diffusive and capacitive contributions recorded at 10–25 mV s⁻¹ (aʺ–cʺ), The percentage contribution of diffusive and capacitive versus scan rate (aʺʹ–cʺ).

3.2. Symmetric Supercapacitor Device (Two‐Electrode Setup)

To evaluate the practical performance of the synthesized electrode materials, a symmetric supercapacitor (SSC) device was assembled. Cyclic voltammetry tests were also performed to investigate their capacitive behavior at various scan rates ranging from 10 to 500 mV s^{− 1}. All three COFs displayed nearly rectangular CV curves up to specific voltage limits, 1.4 V for TTP‐COF and 1.3 V for both BTP‐COF and TP‐COF, indicating ideal capacitive behavior. Beyond these voltages, signs of water oxidation (oxygen evolution reaction, OER) began to appear, which limits the stable operating voltage window (Figure 6a and Figure S15). Notably, at a low scan rate of 10 mV s^{− 1}, a small but broad redox peak emerged in the CV curves. This peak was particularly more pronounced in the TTP‐COF, which also exhibited a higher current density than the other two COFs. This enhanced electrochemical response in TTP‐COF may be attributed to its unique structural features, especially the interconnected porous structure and the presence of the Thieno[3,2‐b]thiophene‐2,5‐dicarbaldehyde linker (Figure 6a), which likely facilitates better ion transport and redox activity. The specific capacitance (Cs) values of three covalent organic frameworks, TTP‐COF, BTP‐COF, and TP‐COF, were evaluated using GCD measurements performed at different current densities. These experiments were conducted at cell voltages of 1.4 V for TTP‐COF and 1.3 V for both BTP‐COF and TP‐COF. The current densities applied ranged from 0.20 to 6.70 A g^{− 1} (specifically: 0.20, 0.33, 0.47, 0.67, 1.00, 2.00, 3.33, 4.70, and 6.70 A g^{− 1}) (Figure 6b and Figure S15). Based on the discharge curves, the specific capacitance values at the lowest current density (0.20 A g^{− 1}) were found to be 129.2 F g^{− 1} for TTP‐COF, 94.4 F g^{− 1} for BTP‐COF, and 85.6 F g^{− 1} for TP‐COF. Additionally, the energy densities of these materials were calculated and determined to be 35.2, 22.2, and 20.1 Wh kg^{− 1} for TTP‐COF, BTP‐COF, and TP‐COF, respectively (Figure 6c,d). The variation in energy density with corresponding power density across the full range of current densities (0.20–6.70 A g^{− 1}) was also analyzed and is presented in Figure 6e. The long‐term electrochemical stability of the synthesized COF‐based electrode materials TTP‐COF, BTP‐COF, and TP‐COF was evaluated by repeated galvanostatic charge‐discharge (GCD) cycling. The cycling stability was analyzed after 2000 cycles, allowing sufficient time for complete electrolyte wetting and electrochemical activation of the electrode, which stabilizes the electrode–electrolyte interface and ensures reliable capacitance values. Specifically, TTP‐COF underwent testing for 25,000 continuous GCD cycles, while both BTP‐COF and TP‐COF were tested for 10,000 cycles. The results, as presented in the respective Figs. (Figure 6f–h), demonstrated excellent cyclic performance for all three materials. After 10,000 cycles, TTP‐COF, BTP‐COF, and TP‐COF retained 97.1%, 95.5%, and 93.2%, respectively of their initial capacitance. also maintained a high capacitance retention of 93.2% over the same number of cycles. Furthermore, TTP‐COF continued to exhibit outstanding durability, showing a capacitance retention of 92.3% even after 25 000 cycles, confirming its superior electrochemical robustness and long‐term stability. To gain deeper insight into the capacitive behavior and variations in internal resistance, Nyquist plots were measured both before and after 25 000 charge–discharge cycles. A minor increase in resistance was observed following the cycling process (Figure 6i). To evaluate possible framework corrosion or dissolution during cycling, the electrolyte collected after electrochemical cycling was first examined through digital images of water, electrolyte before cycling, and electrolyte after cycling, which showed no visible change in color or transparency. The electrolyte was further analyzed using ATR‐FTIR and ¹H NMR spectroscopy (Figure S16). The ATR‐FTIR spectra of the post‐cycling electrolyte show only the characteristic bands of the aqueous 0.5 M K₂SO₄ electrolyte, including O–H stretching (∼3200–3600 cm⁻¹), H–O–H bending (∼1630 cm⁻¹), and SO₄ ^2– stretching (∼1100 cm⁻¹), with no additional peaks associated with organic functional groups from the framework. Similarly, the ¹H NMR spectra of the electrolyte before and after cycling exhibit only the solvent (water) signal at ∼4.7 ppm and the DSS reference peak, without any new resonances in the 0–8 ppm region. These results indicate that no detectable organic species dissolved into the electrolyte, confirming the structural stability of the framework during cycling. The XPS spectra of TTP‐COF and after 20 000 charge–discharge cycles in 0.5 M K₂SO₄ reveal notable surface chemical evolution (Figure S16). In the pristine sample, the C 1s spectrum shows typical components at ∼284.5 eV (sp² C–C), ∼285.5 eV (C–N/C–C), and ∼287.2 eV (C═O). After cycling, while the main peak (∼284.2 eV) is retained, two new features appear at lower binding energies (∼280.5 and ∼282.0 eV) (Figure S17). These low binding energy peaks indicate the formation of electron‐rich carbon environments, which can be attributed to interfacial charge transfer and cation–π interactions with K⁺ ions, along with defect generation and partial reduction of surface functional groups during prolonged cycling. Additionally, the N 1s and S 2p spectra show slight shifts and peak broadening after cycling, suggesting minor changes in their chemical environment due to electrolyte interaction or surface reconstruction. Overall, these results confirm that extended cycling induces electronic modulation and defect formation while preserving the core framework structure.

FIGURE 6.

CV at 10 mV s⁻¹ (a); GCD measurements at 0.2 A g⁻¹ (b); bar plot showing gravimetric specific capacitance (c); bar plot showing energy density (d); ragone plot showing energy density@power density (e); cyclic stability for BTP‐COF (f); cyclic stability for TP‐COF (g); cyclic stability for TTP‐COF (h); Nyquist plots after 25000 cycles (i); Nyquist plots demonstrating the changes in impedance of TTP‐COF, BTP‐COF and TP‐COF in 0.5 M K₂SO₄ (aq.) (j) extended impedance curves (inset) (J′); red LED illumination (k); white LED illumination (l).

EIS was used to analyze charge transfer resistance and ion diffusion at the electrode–electrolyte interface. Figure 6j showed the impedance responses of TTP‐COF, BTP‐COF, and TP‐COF electrodes over a frequency range of 0.01 Hz to 100 kHz (inset, Figure 6i). In the Nyquist plots, the semicircle represents charge transfer resistance (R _ct), while the linear region at low frequencies indicates capacitive behavior. The TTP‐COF electrode showed R _s and R _ct values of 2.57 and 0.18 Ω, respectively, demonstrating lower R _ct than BTP‐COF (0.42 Ω) and TP‐COF (0.24 Ω). The lower resistance and steeper Warburg slope suggest better conductivity and electrochemical performance, highlighting TTP‐COF's potential in redox‐related applications (Figure 6j,jʹ). The real‐world performance of the TTP‐COF‐based prototype supercapacitor was validated through practical demonstration. During the test, the device was first charged with an alternating current (AC) source up to a voltage of 1.4 volts for a duration of 50 s. After charging, the stored energy was utilized to power two types of light‐emitting diodes (LEDs): one white and one red, which acted as the external load (Figures 6,l). Impressively, a single supercapacitor cell was able to illuminate the white LED for a continuous period of 18 s, and the red LED for 5 min and 32 s (Red LED) as shown in Movie S1. These results clearly highlight the effective energy storage and delivery capability of the TTP‐COF device in a practical application (Table 1).

TABLE 1.

Comparing our current work of TPT@BDA‐COF to previous investigations on supercapacitor performance.

		Three‐electrode setup	Two‐electrode setup
Materials	Electrolyte	Csp	Csp	ED	Number of cycles	Refs.
TPDA‐COF	1 M Na2SO4	—	70.6 F g−1	9.8 mW h g−1	10000, 81.5%	[75]
TPT‐DAHQ COF	1 M KOH	256 F g−1	—	—	1800, 98.8%	[76]
COF TDFP‐1	0.1 M H2SO4	354 F g−1	—	—	1000, 95.0%	[77]
TPT@BDA‐COF	1 M NaClO4	92.6 F g−1	47.7 F g−1	21.6 Wh kg−1	10000, 105.2%	[78]
IISERP‐COF10	1 M H2SO4/PVA	—	∼92 mF cm−12	98 µW cm−2	10000, 83%	[79]
IITR‐COF‐1	0.5 M K2SO4	182.6 F g−1	30.7 F g−1	17.0 Wh kg−1	10000, 111.3%	[80]
DqTp COF	1 M H2SO4	154 F g−1	12 mF cm−2	0.43 µW cm−2	2500, 80%	[81]
TTT‐DHTD COF	1 M KOH	273.3 F g−1	—	—	2000, 99%	[82]
DAAQ‐TFP COF	1 M H2SO4	3 mF cm−2	—	—	5000, ∼93%	[83]
TaPaPy	1 M H2SO4	209 F g−1	102 F g−1	9.06 Wh kg−1	6000,92%	[84]
MWCNT@PTZ‐COP	5 M NaClO4	—	55.5 F g−1	37.3 Wh kg−1	20000, 100%	[85]
TTP‐COF	0.5 M K2SO4	193.3 F g− 1	129.2 F g− 1	37.2 Wh kg− 1	25000,107.4%	This work

3.3. Post Characterization

The influence of 10,000 galvanostatic charge–discharge (GCD) cycles on the electrode material BTP‐COF, TP‐COF, and 25000 for TTP‐COF was examined using FESEM) (Figure 7). The analysis revealed noticeable restructuring of the TTP‐COF, BTP‐COF, and TP‐COF microstructures, which led to the development of interconnected pores throughout the morphology. Surface elemental composition showed a reduction in carbon (C: 75.3%) and nitrogen (N: 12.1%) contents, along with a rise in oxygen (O: 12.6%), likely resulting from interactions with the electrolyte.

FIGURE 7.

FESEM analysis of TTP‐COF after 25000 GCD cycles (a), BTP‐COF (b), and TP‐COF (c) after 10000 GCD cycles.

4. Conclusion

This work establishes the successful design of porphyrin‐based covalent organic frameworks integrated with sulfur‐rich π‐conjugated linkers as efficient redox‐active electrodes for aqueous symmetric supercapacitors. Comprehensive structural, spectroscopic, and microscopic analyses confirm the crystalline order, robust imine linkages, and homogeneous elemental distribution within TTP‐COF, BTP‐COF, and TP‐COF. Electrochemical investigations reveal a synergistic energy storage mechanism involving both electric double‐layer capacitance and faradaic pseudocapacitance, enabled by the redox‐active porphyrin cores and sulfur‐containing linkers. Among the series, TTP‐COF demonstrated exceptional performance, delivering a high specific capacitance of 193.3 F g^{− 1} (three‐electrode) and 129.2 F g^{− 1} (two‐electrode), along with an energy density of 37.2 Wh kg^{− 1} and extraordinary cycling durability with 92.3% capacitance retention after 25,000 cycles. Electrochemical impedance studies further highlight its superior charge transfer characteristics (R _ct = 0.18 Ω), validating its efficient ion diffusion and conductive network. The practical applicability of this material was demonstrated through a prototype symmetric device, which successfully powered LEDs for over two minutes. Collectively, these findings highlight that rationally engineered porphyrin‐thiophene COFs, particularly TTP‐COF, bridge the gap between structural stability, redox activity, and conductivity, positioning them as next‐generation, eco‐friendly, and durable electrode materials for high‐performance supercapacitors.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supporting File 1: smll74184‐sup‐0001‐SuppMat.docx.

Supporting File 2: smll74184‐sup‐0002‐MovieS1.mp4.

Data Availability Statement

The data that supports the findings of this study are available in the supplementary material of this article.