Achieving High Capacitance of Paper‐Like Graphene Films by Adsorbing Molecules from Hydrolyzed Polyimide

To date, graphene‐based electric double layer supercapacitors have not shown the remarkable specific capacitance as theoretically predicted. An efficient strategy toward boosting the overall capacitance is to endow graphene with pseudocapacitance. Herein, molecules of hydrolyzed polyimide (HPI) are used to functionalize N‐doped graphene (NG) via π–π interaction and the resulting enhanced electrochemical energy storage is reported. These aromatic molecules in monolayer form on graphene contribute strong pseudocapacitance. Paper‐like NG films with different areal mass loadings ranging from 0.5 to 4.8 mg cm^?2 are prepared for supercapacitor electrodes. It is shown that the gravimetric capacitance can be increased by 50–60% after the surface functionalization by HPI molecules. A high specific capacitance of 553 F g^?1 at 5 mV s^?1 is achieved by the HPI‐NG film with a graphene mass loading of 0.5 mg cm^?2 in H₂SO₄ aqueous electrolyte. For the HPI‐NG film with highest mass loading, the gravimetric specific capacitance drops to 340 F g^?1 while the areal specific capacitance reaches a high value of 1.7 F cm^?2. HPI‐NG films are also tested in Li₂SO₄ aqueous electrolyte, over an extended voltage window of 1.6 V. High specific energy densities up to 40 Wh kg^?1 are achieved with the Li₂SO₄ electrolyte.     

Disassembly–Reassembly Approach to RuO2/Graphene Composites for Ultrahigh Volumetric Capacitance Supercapacitor

A porous, yet compact, RuO₂/graphene hybrid is successfully prepared by using a disassembly–reassembly strategy, achieving effective and uniform loading of RuO₂ nanoparticles inside compact graphene monolith. The disassembly process ensures the uniform loading of RuO₂ nanoparticles into graphene monolith, while the reassembly process guarantees a high density yet simultaneously unimpeded ion transport channel in the composite. The resulting RuO₂/graphene hybrid possesses a density of 2.63 g cm⁻³, leading to a record high volumetric capacitance of 1485 F cm⁻³ at the current density of 0.1 A g⁻¹. When the current density is increased to 20 A g⁻¹, it remains a high volumetric capacitance of 1188 F cm⁻³. More importantly, when the single electrode mass loading is increased to 12 mg cm⁻², it still delivers a high volumetric capacitance of 1415 F cm⁻³ at the current density of 0.1 A g⁻¹, demonstrating the promise of this disassembly–reassembly approach to create high volumetric performance materials for energy storage applications.     

High Performance of N‐Doped Graphene with Bubble‐like Textures for Supercapacitors

Nitrogen‐doped graphene (NG) with wrinkled and bubble‐like texture is fabricated by a thermal treatment. Especially, a novel sonication‐assisted pretreatment with nitric acid is used to further oxidize graphene oxide and its binding with melamine molecules. There are many bubble‐like nanoflakes with a dimension of about 10 nm appeared on the undulated graphene nanosheets. The bubble‐like texture provides more active sites for effective ion transport and reversible capacitive behavior. The specific surface area of NG (5.03 at% N) can reach up to 438.7 m² g^?1, and the NG electrode demonstrates high specific capacitance (481 F g^?1 at 1 A g^?1, four times higher than reduced graphene oxide electrode (127.5 F g^?1)), superior cycle stability (the capacitance retention of 98.9% in 2 m KOH and 99.2% in 1 m H₂SO₄ after 8000 cycles), and excellent energy density (42.8 Wh kg^?1 at power density of 500 W kg^?1 in 2 m KOH aqueous electrolyte). The results indicate the potential use of NG as graphene‐based electrode material for energy storage devices.     

Vertically Aligned Graphene–Carbon Fiber Hybrid Electrodes with Superlong Cycling Stability for Flexible Supercapacitors

Graphene electrode–based supercapacitors are in high demand due to their superior electrochemical characteristics. A major bottleneck of using the supercapacitors for commercial applications lies in their inferior electrode cycle life. Herein, a simple and facile method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically stacked and electrically connected to the carbon fibers which can result in vertically aligned graphene–carbon fiber nanostructure is developed. The vertically aligned graphene–carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous 3D architecture which enabled faster and efficient electrolyte‐ion diffusion with a gravimetric capacitance of 333.3 F g^?1 and an areal capacitance of 166 mF cm^?2. The electrodes displayed superlong electrochemical cycling stability of more than 100 000 cycles with 100% capacitance retention hence promising for long‐lasting supercapacitors. Apart from the electrochemical double layer charge storage, the oxygen‐containing surface moieties and α‐Ni(OH)₂ present on the graphene sheets enhance the charge storage by faradaic reactions. This enables the assembled device to provide an excellent gravimetric energy density of 76 W h kg^?1 with a 100% capacitance retention even after 1000 bending cycles. This study opens the door for developing high‐performing flexible graphene electrodes for wearable energy storage applications.     

Vertically Oriented Graphene Nanoribbon Fibers for High‐Volumetric Energy Density All‐Solid‐State Asymmetric Supercapacitors

Graphene fiber based micro‐supercapacitors (GF micro‐SCs) have attracted great attention for their potential applications in portable and wearable electronics. However, due to strong π–π stacking of nanosheets for graphene fibers, the limited ion accessible surface area and slow ion diffusion rate leads to low specific capacitance and poor rate performance. Here, the authors report a strategy for the synthesis of a vertically oriented graphene nanoribbon fiber with highly exposed surface area through confined‐hydrothermal treatment of interconnected graphene oxide nanoribbons and consequent laser irradiation process. As a result, the as‐obtained fiber shows high length specific capacitance of 3.2 mF cm^?1 and volumetric capacitance of 234.8 F cm^?3 at 2 mV s^?1, as well as excellent rate capability and outstanding cycling performance (96% capacitance retention after 10 000 cycles). Moreover, an all‐solid‐state asymmetric supercapacitor based on graphene nanoribbon fiber as negative electrode and MnO₂ coated graphene ribbon fiber as positive electrode, shows high volumetric capacitance and energy density of 12.8 F cm^?3 and 5.7 mWh cm^?3 (normalized to the device volume), respectively, much higher than those of previously reported GF micro‐SCs, as well as a long cycle life with 88% of capacitance retention after 10 000 cycles.     

3D Printing of Freestanding MXene Architectures for Current‐Collector‐Free Supercapacitors

Additive manufacturing (AM) technologies appear as a paradigm for scalable manufacture of electrochemical energy storage (EES) devices, where complex 3D architectures are typically required but are hard to achieve using conventional techniques. The combination of these technologies and innovative material formulations that maximize surface area accessibility and ion transport within electrodes while minimizing space are of growing interest. Herein, aqueous inks composed of atomically thin (1–3 nm) 2D Ti₃C₂T_x with large lateral size of about 8 µm possessing ideal viscoelastic properties are formulated for extrusion‐based 3D printing of freestanding, high specific surface area architectures to determine the viability of manufacturing energy storage devices. The 3D‐printed device achieves a high areal capacitance of 2.1 F cm^?2 at 1.7 mA cm^?2 and a gravimetric capacitance of 242.5 F g^?1 at 0.2 A g^?1 with a retention of above 90% capacitance for 10 000 cycles. It also exhibits a high energy density of 0.0244 mWh cm^?2 and a power density of 0.64 mW cm^?2 at 4.3 mA cm^?2. It is anticipated that the sustainable printing and design approach developed in this work can be applied to fabricate high‐performance bespoke multiscale and multidimensional architectures of functional and structural materials for integrated devices in various applications.     

Nitrogen‐Doped Carbon Membrane Derived from Polyimide as Free‐Standing Electrodes for Flexible Supercapacitors

Nitrogen‐doped carbon materials have attracted great interest in the energy storage due to the better electrochemical performances than the pristine carbon materials. In this work, a heterocyclic polyimide containing benzopyrrole and benzimidazole rings is carbonized to fabricate the free‐standing and flexible carbon membrane (Carbon_PI) with a high packing density (0.89 cm^?3), in which the location of nitrogen atoms in the doped configurations is easily controlled. XPS analysis indicates that quaternary nitrogen is the predominant nitrogen‐doped configurations. The high content of nitrogen effectively improves the wettability of the electrode materials. The Carbon_PI membrane exhibits excellent volumetric capacitance (159.3 F cm^?3 at 1 A g^?1), high rate capability (127.5 F cm^?3 at 7 A g^?1), and long cycle life. TEM images reveal the very slight change of the microstructure of graphitic nanosheet of Carbon_PI during the long charge/discharge cycles.     

Hierarchical 3D All‐Carbon Composite Structure Modified with N‐Doped Graphene Quantum Dots for High‐Performance Flexible Supercapacitors

Flexible supercapacitors have shown enormous potential for portable electronic devices. Herein, hierarchical 3D all‐carbon electrode materials are prepared by assembling N‐doped graphene quantum dots (N‐GQDs) on carbonized MOF materials (cZIF‐8) interweaved with carbon nanotubes (CNTs) for flexible all‐solid‐state supercapacitors. In this ternary electrode, cZIF‐8 provides a large accessible surface area, CNTs act as the electrical conductive network, and N‐GQDs serve as highly pseudocapactive materials. Due to the synergistic effect and hierarchical assembly of these components, N‐GQD@cZIF‐8/CNT electrodes exhibit a high specific capacitance of 540 F g^?1 at 0.5 A g^?1 in a 1 m H₂SO₄ electrolyte and excellent cycle stability with 90.9% capacity retention over 8000 cycles. The assembled supercapacitor possesses an energy density of 18.75 Wh kg^?1 with a power density of 108.7 W kg^?1. Meanwhile, three supercapacitors connected in series can power light‐emitting diodes for 20 min. All‐solid‐state N‐GQD@cZIF‐8/CNT flexible supercapacitor exhibits an energy density of 14 Wh kg^?1 with a power density of 89.3 W kg^?1, while the capacitance retention after 5000 cycles reaches 82%. This work provides an effective way to construct novel electrode materials with high energy storage density as well as good cycling performance and power density for high‐performance energy storage devices via the rational design.     

MoS2/NiS Yolk–Shell Microsphere‐Based Electrodes for Overall Water Splitting and Asymmetric Supercapacitor

Rational designing of the composition and structure of electrode material is of great significance for achieving highly efficient energy storage and conversion in electrochemical energy devices. Herein, MoS₂/NiS yolk–shell microspheres are successfully synthesized via a facile ionic liquid‐assisted one‐step hydrothermal method. With the favorable interface effect and hollow structure, the electrodes assembled with MoS₂/NiS hybrid microspheres present remarkably enhanced electrochemical performance for both overall water splitting and asymmetric supercapacitors. In particular, to deliver a current density of 10 mA cm^?2, the MoS₂/NiS‐based electrolysis cell for overall water splitting only needs an output voltage of 1.64 V in the alkaline medium, lower than that of Pt/C–IrO₂‐based electrolysis cells (1.70 V). As an electrode for supercapacitors, the MoS₂/NiS hybrid microspheres exhibit a specific capacitance of 1493 F g^?1 at current density of 0.2 A g^?1, and remain 1165 F g^?1 even at a large current density of 2 A g^?1, implying outstanding charge storage capacity and excellent rate performance. The MoS₂/NiS‐ and active carbon‐based asymmetric supercapacitor manifests a maximum energy density of 31 Wh kg^?1 at a power density of 155.7 W kg^?1, and remarkable cycling stability with a capacitance retention of approximately 100% after 10 000 cycles.     

Nano‐RuO2‐Decorated Holey Graphene Composite Fibers for Micro‐Supercapacitors with Ultrahigh Energy Density

Compactness and versatility of fiber‐based micro‐supercapacitors (FMSCs) make them promising for emerging wearable electronic devices as energy storage solutions. But, increasing the energy storage capacity of microscale fiber electrodes, while retaining their high power density, remains a significant challenge. Here, this issue is addressed by incorporating ultrahigh mass loading of ruthenium oxide (RuO₂) nanoparticles (up to 42.5 wt%) uniformly on nanocarbon‐based microfibers composed largely of holey reduced graphene oxide (HrGO) with a lower amount of single‐walled carbon nanotubes as nanospacers. This facile approach involes (1) space‐confined hydrothermal assembly of highly porous but 3D interconnected carbon structure, (2) impregnating wet carbon structures with aqueous Ru³⁺ ions, and (3) anchoring RuO₂ nanoparticles on HrGO surfaces. Solid‐state FMSCs assembled using those fibers demonstrate a specific volumetric capacitance of 199 F cm^?3 at 2 mV s^?1. Fabricated FMSCs also deliver an ultrahigh energy density of 27.3 mWh cm^?3, the highest among those reported for FMSCs to date. Furthermore, integrating 20 pieces of FMSCs with two commercial flexible solar cells as a self‐powering energy system, a light‐emitting diode panel can be lit up stably. The current work highlights the excellent potential of nano‐RuO₂‐decorated HrGO composite fibers for constructing micro‐supercapacitors with high energy density for wearable electronic devices.     

Rational Design of Statically and Dynamically Stable Lithium–Sulfur Batteries with High Sulfur Loading and Low Electrolyte/Sulfur Ratio

The primary challenge with lithium–sulfur battery research is the design of sulfur cathodes that exhibit high electrochemical efficiency and stability while keeping the sulfur content and loading high and the electrolyte/sulfur ratio low. With a systematic investigation, a novel graphene/cotton‐carbon cathode is presented here that enables sulfur loading and content as high as 46 mg cm^?2 and 70 wt% with an electrolyte/sulfur ratio of as low as only 5. The graphene/cotton‐carbon cathodes deliver peak capacities of 926 and 765 mA h g^?1, respectively, at C/10 and C/5 rates, which translate into high areal, gravimetric, and volumetric capacities of, respectively, 43 and 35 mA h cm^?2, 648 and 536 mA h g^?1, and 1067 and 881 mA h cm^?3 with a stable cyclability. They also exhibit superior cell‐storage capability with 95% capacity‐retention, a low self‐discharge constant of just 0.0012 per day, and stable poststorage cyclability after storing over a long period of six months. This work demonstrates a viable approach to develop lithium–sulfur batteries with practical energy densities exceeding that of lithium‐ion batteries.     

Graphene‐Based Linear Tandem Micro‐Supercapacitors with Metal‐Free Current Collectors and High‐Voltage Output

Printable supercapacitors are regarded as a promising class of microscale power source, but are facing challenges derived from conventional sandwich‐like geometry. Herein, the printable fabrication of new‐type planar graphene‐based linear tandem micro‐supercapacitors (LTMSs) on diverse substrates with symmetric and asymmetric configuration, high‐voltage output, tailored capacitance, and outstanding flexibility is demonstrated. The resulting graphene‐based LTMSs consisting of 10 micro‐supercapacitors (MSs) present efficient high‐voltage output of 8.0 V, suggestive of superior uniformity of the entire integrated device. Meanwhile, LTMSs possess remarkable flexibility without obvious capacitance degradation under different bending states. Moreover, areal capacitance of LTMSs can be sufficiently modulated by incorporating polyaniline‐based pseudocapacitive nanosheets into graphene electrodes, showing enhanced capacitance of 7.6 mF cm^?2. To further improve the voltage output and energy density, asymmetric LTMSs are fabricated through controlled printing of linear‐patterned graphene as negative electrodes and MnO₂ nanosheets as positive electrodes. Notably, the asymmetric LTMSs from three serially connected MSs are easily extended to 5.4 V, triple voltage output of the single cell (1.8 V), suggestive of the versatile applicability of this technique. Therefore, this work offers numerous opportunities of graphene and analogous nanosheets for one‐step scalable fabrication of flexible tandem energy storage devices integrating with printed electronics on same substrate.     

Hydrothermally Oxidized Single‐Walled Carbon Nanotube Networks for High Volumetric Electrochemical Energy Storage

Improving volumetric energy density is one of the major challenges in nanostructured carbon electrodes for electrochemical energy storage device applications. Herein, a simple hydrothermal oxidation process of single‐walled carbon nanotube (SWNT) networks in dilute nitric acid is reported, enabling simultaneous physical densification and chemical functionalization of the as‐assembled randomly‐packed SWNT films. After the hydrothermal oxidation process, the density of the SWNT films increases from 0.63 to 1.02 g cm^?3 and a considerable amount of redox‐active oxygen functional groups are introduced on the surface of the SWNTs. The functionalized SWNT films are used as positive electrodes against Li metal negative electrodes for potential Li‐ion capacitors or Li‐ion battery applications. The functionalized SWNT electrodes deliver high volumetric as well as gravimetric capacities, 154 Ah L^?1 and 152 mAh g^?1, respectively, owing to the surface redox reactions between the introduced oxygen functional groups and Li ions. In addition, these electrodes exhibit a remarkable rate‐capability by retaining its high capacity of 94 Ah L^?1 (92 mAh g^?1) at a high discharge rate of 10 A g^?1. These results demonstrate the simple hydrothermal oxidation process as an attractive strategy for improving the volumetric performance of nanostructured carbon electrodes.     

A Metal–Organic Framework with Optimized Porosity and Functional Sites for High Gravimetric and Volumetric Methane Storage Working Capacities

Extensive research has been devoted to developing new porous materials with high methane storage capacity. While great progress has been made in recent years, it still remains very challenging to target simultaneously high gravimetric and volumetric methane (CH₄) working capacities (deliverable amount between 5.8 and 65 bar) in a single material. Here, a novel metal–organic framework (termed as UTSA‐110a) constructed by an extended linker containing a high density of functional nitrogen sites, exhibiting both very high gravimetric and volumetric working capacities of 317 cm³ (STP: 273.15 K, 1 atm) g^?1 and 190 cm³ (STP) cm^?3, respectively, for robust MOFs, is reported. Both of these values are higher than those of two benchmark materials: HKUST‐1 (207 cm³ (STP) g^?1 or 183 cm³ (STP) cm^?3) and UTSA‐76a (267 cm³ (STP) g^?1 or 187 cm³ (STP) cm^?3). Computational studies reveal that it is the combination of optimized porosity and favorable binding sites that leads to the simultaneously high gravimetric and volumetric working capacities in this material.     

Strong Charge Transfer at 2H–1T Phase Boundary of MoS2 for Superb High‐Performance Energy Storage

Transition metal dichalcogenides exhibit several different phases (e.g., semiconducting 2H, metallic 1T, 1T′) arising from the collective and sluggish atomic displacements rooted in the charge‐lattice interaction. The coexistence of multiphase in a single sheet enables ubiquitous heterophase and inhomogeneous charge distribution. Herein, by combining the first‐principles calculations and experimental investigations, a strong charge transfer ability at the heterophase boundary of molybdenum disulfide (MoS₂) assembled together with graphene is reported. By modulating the phase composition in MoS₂, the performance of the nanohybrid for energy storage can be modulated, whereby remarkable gravimetric and volumetric capacitances of 272 F g^?1 and 685 F cm^?3 are demonstrated. As a proof of concept for energy application, a flexible solid‐state asymmetric supercapacitor is constructed with the MoS₂‐graphene heterolayers, which shows superb energy and power densities (46.3 mWh cm^?3 and 3.013 W cm^?3, respectively). The present work demonstrates a new pathway for efficient charge flow and application in energy storage by engineering the phase boundary and interface in 2D materials of transition metal dichalcogenides.     

Nitrogen‐Superdoped 3D Graphene Networks for High‐Performance Supercapacitors

An N‐superdoped 3D graphene network structure with an N‐doping level up to 15.8 at% for high‐performance supercapacitor is designed and synthesized, in which the graphene foam with high conductivity acts as skeleton and nested with N‐superdoped reduced graphene oxide arogels. This material shows a highly conductive interconnected 3D porous structure (3.33 S cm^?1), large surface area (583 m² g^?1), low internal resistance (0.4 Ω), good wettability, and a great number of active sites. Because of the multiple synergistic effects of these features, the supercapacitors based on this material show a remarkably excellent electrochemical behavior with a high specific capacitance (of up to 380, 332, and 245 F g^?1 in alkaline, acidic, and neutral electrolytes measured in three‐electrode configuration, respectively, 297 F g^?1 in alkaline electrolytes measured in two‐electrode configuration), good rate capability, excellent cycling stability (93.5% retention after 4600 cycles), and low internal resistance (0.4 Ω), resulting in high power density with proper high energy density.     

Interlayer Hydrogen‐Bonded Metal Porphyrin Frameworks/MXene Hybrid Film with High Capacitance for Flexible All‐Solid‐State Supercapacitors

2D metal‐porphyrin frameworks (MPFs) are attractive for advanced energy storage devices. However, the inferior conductivity and low structural stability of MPFs seriously limit their application as flexible free‐standing electrodes with high performance. Here, for the first time, an interlayer hydrogen‐bonded MXene/MPFs film is proposed to overcome these disadvantages by intercalation of highly conductive MXene nanosheets into MPFs nanosheets via a vacuum‐assisted filtration technology. The alternant insertion of MXene and MPFs affords 3D interconnected “MPFs‐to‐MXene‐to‐MPFs” conductive networks to accelerate the ionic/electronic transport rates. Meanwhile, the interlayer hydrogen bonds (F···H? O and O···H? O) contribute a high chemical stability due to a favorable tolerance to volume change caused by phase separation and structural collapse during the charge/discharge process. The synergistic effect makes MXene/MPFs film deliver a capacitance of 326.1 F g^?1 at 0.1 A g^?1, 1.64 F cm^?2 at 1 mA cm^?2, 694.2 F cm^?3 at 1 mA cm^?3 and a durability of about 30 000 cycles. The flexible symmetric supercapacitor shows an areal capacitance of 408 mF cm^?2, areal energy density of 20.4 µW h cm^?2, and capacitance retention of 95.9% after 7000 cycles. This work paves an avenue for the further exploration of 2D MOFs in flexible energy storage devices.     

Design of 3D Graphene‐Oxide Spheres and Their Derived Hierarchical Porous Structures for High Performance Supercapacitors

Graphene‐oxide (GO) based porous structures are highly desirable for supercapacitors, as the charge storage and transfer can be enhanced by advancement in the synthesis. An effective route is presented of, first, synthesis of three‐dimensional (3D) assembly of GO sheets in a spherical architecture (GOS) by flash‐freezing of GO dispersion, and then development of hierarchical porous graphene (HPG) networks by facile thermal‐shock reduction of GOS. This leads to a superior gravimetric specific capacitance of ≈306 F g⁻¹ at 1.0 A g⁻¹, with a capacitance retention of 93% after 10 000 cycles. The values represent a significant capacitance enhancement by 30–50% compared with the GO powder equivalent, and are among the highest reported for GO‐based structures from different chemical reduction routes. Furthermore, a solid‐state flexible supercapacitor is fabricated by constructing the HPG with polymer gel electrolyte, exhibiting an excellent areal specific capacitance of ≈220 mF cm⁻² at 1.0 mA cm⁻² with exceptional cyclic stability. The work reveals a facile but efficient synthesis approach of GO‐based materials to enhance the capacitive energy storage.     

Nitrogen‐Doped Carbon Encapsulated Mesoporous Vanadium Nitride Nanowires as Self‐Supported Electrodes for Flexible All‐Solid‐State Supercapacitors

Flexible 3D nanoarchitectures have received tremendous interest recently because of their potential applications in flexible/wearable energy storage devices. Herein, 3D intertwined nitrogen‐doped carbon encapsulated mesoporous vanadium nitride nanowires (MVN@NC NWs) are investigated as thin, lightweight, and self‐supported electrodes for flexible supercapacitors (SCs). The MVN NWs have abundant active sites accessible to charge storage, and the N‐doped carbon shell suppresses electrochemical dissolution of the inner MVN NWs in an alkaline electrolyte, leading to excellent capacitive properties. The flexible MVN@NC NWs film electrode delivers a high areal capacitance of 282 mF cm⁻² and exhibits excellent long‐term stability with 91.8% capacitance retention after 12 000 cycles in a KOH electrolyte. All‐solid‐state flexible SCs assembled by sandwiching two flexible MVN@NC NWs film electrodes with alkaline poly(vinyl alcohol) (PVA), sodium polyacrylate, and KOH gel electrolyte boast a high volumetric capacitance of 10.9 F cm⁻³, an energy density of 0.97 mWh cm⁻³, and a power density of 2.72 W cm⁻³ at a current density of 0.051 A cm⁻³ based on the entire cell. By virtue of the excellent mechanical flexibility, high capacitance, and large energy/power density, the self‐supported MVN@NC NWs paper‐like electrodes have large potential applications in portable and wearable flexible electronics.     

Stretchable All‐Gel‐State Fiber‐Shaped Supercapacitors Enabled by Macromolecularly Interconnected 3D Graphene/Nanostructured Conductive Polymer Hydrogels

Nanostructured conductive polymer hydrogels (CPHs) have been extensively applied in energy storage owing to their advantageous features, such as excellent electrochemical activity and relatively high electrical conductivity, yet the fabrication of self‐standing and flexible electrode‐based CPHs is still hampered by their limited mechanical properties. Herein, macromolecularly interconnected 3D graphene/nanostructured CPH is synthesized via self‐assembly of CPHs and graphene oxide macrostructures. The 3D hybrid hydrogel shows uniform interconnectivity and enhanced mechanical properties due to the strong macromolecular interaction between the CPHs and graphene, thus greatly reducing aggregation in the fiber‐shaping process. A proof‐of‐concept all‐gel‐state fibrous supercapacitor based on the 3D polyaniline/graphene hydrogel is fabricated to demonstrate the outstanding flexibility and mouldability, as well as superior electrochemical properties enabled by this 3D hybrid hydrogel design. The proposed device can achieve a large strain (up to ≈40%), and deliver a remarkable volumetric energy density of 8.80 mWh cm^?3 (at power density of 30.77 mW cm^?3), outperforming many fiber‐shaped supercapacitors reported previously. The all‐hydrogel design opens up opportunities in the fabrication of next‐generation wearable and portable electronics.