Nanostructured Ternary Electrodes for Energy‐Storage Applications

A three‐component, flexible electrode is developed for supercapacitors over graphitized carbon fabric, utilizing γ‐MnO₂ nanoflowers anchored onto carbon nanotubes (γ‐MnO₂/CNT) as spacers for graphene nanosheets (GNs). The three‐component, composite electrode doubles the specific capacitance with respect to GN‐only electrodes, giving the highest‐reported specific capacitance (308 F g^?1) for symmetric supercapacitors containing MnO₂ and GNs using a two‐electrode configuration, at a scan rate of 20 mV s^?1. A maximum energy density of 43 W h kg^?1 is obtained for our symmetric supercapacitors at a constant discharge‐current density of 2.5 A g^?1 using GN–(γ‐MnO₂/CNT)‐nanocomposite electrodes. The fabricated supercapacitor device exhibits an excellent cycle life by retaining ≈90% of the initial specific capacitance after 5000 cycles.     

3D Printing Quasi‐Solid‐State Asymmetric Micro‐Supercapacitors with Ultrahigh Areal Energy Density

A 3D printing approach is first developed to fabricate quasi‐solid‐state asymmetric micro‐supercapacitors to simultaneously realize the efficient patterning and ultrahigh areal energy density. Typically, cathode, anode, and electrolyte inks with high viscosities and shear‐thinning rheological behaviors are first prepared and 3D printed individually on the substrates. The 3D printed asymmetric micro‐supercapacitor with interdigitated electrodes exhibits excellent structural integrity, a large areal mass loading of 3.1 mg cm^?2, and a wide electrochemical potential window of 1.6 V. Consequently, this 3D printed asymmetric micro‐supercapacitor displays an ultrahigh areal capacitance of 207.9 mF cm^?2. More importantly, an areal energy density of 73.9 µWh cm^?2 is obtained, superior to most reported interdigitated micro‐supercapacitors. It is believed that the efficient 3D printing strategy can be used to construct various asymmetric micro‐supercapacitors to promote the integration in on‐chip energy storage systems.     

One‐Step Fabrication of Ultrathin Porous Nickel Hydroxide‐Manganese Dioxide Hybrid Nanosheets for Supercapacitor Electrodes with Excellent Capacitive Performance

A facile one‐step hydrothermal co‐deposition method for growth of ultrathin Ni(OH)₂‐MnO₂ hybrid nanosheet arrays on three dimensional (3D) macroporous nickel foam is presented. Due to the highly hydrophilic and ultrathin nature of hybrid nanosheets, as well as the synergetic effects of Ni(OH)₂ and MnO₂, the as‐fabricated Ni(OH)₂‐MnO₂ hybrid electrode exhibits an ultrahigh specific capacitance of 2628 F g^?1. Moreover, the asymmetric supercapacitor with the as‐obtained Ni(OH)₂‐MnO₂ hybrid film as the positive electrode and the reduced graphene oxide as the negative electrode has a high energy density (186 Wh kg^?1 at 778 W kg^?1), based on the total mass of active materials.     

All‐Solid‐State Fiber Supercapacitors with Ultrahigh Volumetric Energy Density and Outstanding Flexibility

Fiber supercapacitors (FSCs) represent a promising class of energy storage devices that can complement or even replace microbatteries in miniaturized portable and wearable electronics. One of their main limitations, however, is the low volumetric energy density when compared with those of rechargeable batteries. Considering the energy density of FSC is proportional to CV² (E = 1/2 CV², where C is the capacitance and V is the operating voltage), one would explore high operating voltage as an effective strategy to promote the volumetric energy density. In the present work, an all‐solid‐state asymmetric FSC (AFSC) with a maximum operating voltage of 3.5 V is successfully achieved, by employing an ionic liquid (IL) incorporated gel‐polymer as the electrolyte (EMIMTFSI/PVDF‐HFP). The optimized AFSC is based on MnO_x@TiN nanowires@carbon nanotube (NWs@CNT) fiber as the positive electrode and C@TiN NWs@CNT fiber as the negative electrode, which gives rise to an ultrahigh stack volumetric energy density of 61.2 mW h cm^?3, being even comparable to those of commercially planar lead‐acid batteries (50–90 mW h cm^?3), and an excellent flexibility of 92.7% retention after 1000 blending cycles at 90°. The demonstration of employing the ILs‐based electrolyte opens up new opportunities to fabricate high‐performance flexible AFSC for future portable and wearable electronic devices.     

Ultrafast All‐Solid‐State Coaxial Asymmetric Fiber Supercapacitors with a High Volumetric Energy Density

Fiber‐supercapacitors (FSCs) are promising energy storage devices that can complement or even replace microbatteries in miniaturized portable and wearable electronics. Currently, a major challenge for FSCs is achieving ultrahigh volumetric energy and power densities simultaneously, especially when the charge/discharge rates exceed 1 V s^?1. Herein, an Au‐nanoparticle‐doped‐MnO_x@CoNi‐alloy@carbon‐nanotube (Au–MnO_x@CoNi@CNT) core/shell nanocomposite fiber electrode is designed, aiming to boost its charge/discharge rate by taking advantage of the superconductive CoNi alloy network and the greatly enhanced conductivity of the Au doped MnO_x active materials. An all‐solid‐state coaxial asymmetric FSC (CAFSC) prototype device made by wrapping this fiber with a holey graphene paper (HGP) exhibits excellent performance at rates up to 10 V s^?1, which is the highest charge rate demonstrated so far for FSCs based on pseudocapacitive materials. Furthermore, our fully packaged CAFSC delivers a volumetric energy density of ≈15.1 mW h cm^?3, while simultaneously maintaining a high power density of 7.28 W cm^?3 as well as a long cycle life (90% retention after 10 000 cycles). This value is the highest among all reported FSCs, even better than that of a typical 4 V/500 µA h thin‐film lithium battery.     

Flexible Asymmetric Micro‐Supercapacitors Based on Bi2O3 and MnO2 Nanoflowers: Larger Areal Mass Promises Higher Energy Density

A flexible asymmetric supercapacitor (ASC) with high energy density is designed and fabricated using flower‐like Bi₂O₃ and MnO₂ grown on carbon nanofiber (CNF) paper as the negative and positive electrodes, respectively. The lightweight (1.6 mg cm^?2), porous, conductive, and flexible features make the CNF paper an ideal support for guest active materials, which permit a large areal mass of 9 mg cm^?2 for Bi₂O₃ (≈85 wt% of the entire electrode). Thus, the optimal device with an operation voltage of 1.8 V can deliver a high energy density of 43.4 μWh cm^?2 (11.3 W h kg^?1, based on the total electrodes) and a maximum power density of 12.9 mW cm^?2 (3370 W kg^?1). This work provides an example of large areal mass and flexible electrode for ASCs with high areal capacitance and high energy density, holding great promise for future flexible electronic devices.     

Structure‐Controlled,Vertical Graphene‐Based,Binder‐Free Electrodes from Plasma‐Reformed Butter Enhance Supercapacitor Performance

Vertical graphene nanosheets (VGNS) hold great promise for high‐performance supercapacitors owing to their excellent electrical transport property, large surface area and in particular, an inherent three‐dimensional, open network structure. However, it remains challenging to materialise the VGNS‐based supercapacitors due to their poor specific capacitance, high temperature processing, poor binding to electrode support materials, uncontrollable microstructure, and non‐cost effective way of fabrication. Here we use a single‐step, fast, scalable, and environmentally‐benign plasma‐enabled method to fabricate VGNS using cheap and spreadable natural fatty precursor butter, and demonstrate the controllability over the degree of graphitization and the density of VGNS edge planes. Our VGNS employed as binder‐free supercapacitor electrodes exhibit high specific capacitance up to 230 F g^?1 at a scan rate of 10 mV s^?1 and >99% capacitance retention after 1,500 charge‐discharge cycles at a high current density, when the optimum combination of graphitic structure and edge plane effects is utilised. The energy storage performance can be further enhanced by forming stable hybrid MnO₂/VGNS nano‐architectures which synergistically combine the advantages from both VGNS and MnO₂. This deterministic and plasma‐unique way of fabricating VGNS may open a new avenue for producing functional nanomaterials for advanced energy storage devices.     

High‐Performance Fiber‐Shaped All‐Solid‐State Asymmetric Supercapacitors Based on Ultrathin MnO2 Nanosheet/Carbon Fiber Cathodes for Wearable Electronics

Flexible fiber‐shaped supercapacitors have shown great potential in portable and wearable electronics. However, small specific capacitance and low operating voltage limit the practical application of fiber‐shaped supercapacitors in high energy density devices. Herein, direct growth of ultrathin MnO₂ nanosheet arrays on conductive carbon fibers with robust adhesion is exhibited, which exhibit a high specific capacitance of 634.5 F g^?1 at a current density of 2.5 A g^?1 and possess superior cycle stability. When MnO₂ nanosheet arrays on carbon fibers and graphene on carbon fibers are used as a positive electrode and a negative electrode, respectively, in an all‐solid‐state asymmetric supercapacitor (ASC), the ASC displays a high specific capacitance of 87.1 F g^?1 and an exceptional energy density of 27.2 Wh kg^?1. In addition, its capacitance retention reaches 95.2% over 3000 cycles, representing the excellent cyclic ability. The flexibility and mechanical stability of these ASCs are highlighted by the negligible degradation of their electrochemical performance even under severely bending states. Impressively, as‐prepared fiber‐shaped ASCs could successfully power a photodetector based on CdS nanowires without applying any external bias voltage. The excellent performance of all‐solid‐state ASCs opens up new opportunity for development of wearable and self‐powered nanodevices in near future.     

3D‐Printed Stretchable Micro‐Supercapacitor with Remarkable Areal Performance

While stretchable micro‐supercapacitors (MSCs) have been realized, they have suffered from limited areal electrochemical performance, thus greatly restricting their practical electronic application. Herein, a facile strategy of 3D printing and unidirectional freezing of a pseudoplastic nanocomposite gel composed of Ti₃C₂T_x MXene nanosheets, manganese dioxide nanowire, silver nanowires, and fullerene to construct intrinsically stretchable MSCs with thick and honeycomb‐like porous interdigitated electrodes is introduced. The unique architecture utilizes thick electrodes and a 3D porous conductive scaffold in conjunction with interacting material properties to achieve higher loading of active materials, larger interfacial area, and faster ion transport for significantly improved areal energy and power density. Moreover, the oriented cellular scaffold with fullerene‐induced slippage cell wall structure prompts the printed electrode to withstand large deformations without breaking or exhibiting obvious performance degradation. When imbued with a polymer gel electrolyte, the 3D‐printed MSC achieves an unprecedented areal capacitance of 216.2 mF cm^?2 at a scan rate of 10 mV s^?1, and remains stable when stretched up to 50% and after 1000 stretch/release cycles. This intrinsically stretchable MSC also exhibits high rate capability and outstanding areal energy density of 19.2 µWh cm^?2 and power density of 58.3 mW cm^?2, outperforming all reported stretchable MSCs.     

Hydrous RuO2‐Decorated MXene Coordinating with Silver Nanowire Inks Enabling Fully Printed Micro‐Supercapacitors with Extraordinary Volumetric Performance

The fabrication of fully printable, flexible micro‐supercapacitors (MSCs) with high energy and power density remains a significant technological hurdle. To overcome this grand challenge, the 2D material MXene has garnered significant attention for its application, among others, as a printable electrode material for high performing electrochemical energy storage devices. Herein, a facile and in situ process is proposed to homogeneously anchor hydrous ruthenium oxide (RuO₂) nanoparticles on Ti₃C₂T_x MXene nanosheets. The resulting RuO₂@MXene nanosheets can associate with silver nanowires (AgNWs) to serve as a printable electrode with micrometer‐scale resolution for high performing, fully printed MSCs. In this printed nanocomposite electrode, the RuO₂ nanoparticles contribute high pseudocapacitance while preventing the MXene nanosheets from restacking, ensuring an effective ion highway for electrolyte ions. The AgNWs coordinate with the RuO₂@MXene to guarantee the rheological property of the electrode ink, and provide a highly conductive network architecture for rapid charge transport. As a result, MSCs printed from the nanocomposite inks demonstrate volumetric capacitances of 864.2 F cm^?3 at 1 mV s^?1, long‐term cycling performance (90% retention after 10 000 cycles), good rate capability (304.0 F cm^?3 at 2000 mV s^?1), outstanding flexibility, remarkable energy (13.5 mWh cm^?3) and power density (48.5 W cm^?3).     

Antimonene Engineered Highly Deformable Freestanding Electrode with Extraordinarily Improved Energy Storage Performance

Advanced 2D materials have spurred great interest as a new paradigm in pursuing improved energy storage performance. Herein, for the first time, antimonene is utilized as an effective active component for constructing highly deformable and editable freestanding film electrodes, as the basis of a supercapacitor with record‐breaking electrode performance. The insertion of antimonene is able to improve the environmental stability of the antimonene/MXene composite electrode and remarkably enhance the energy storage capability in both protic and neutral electrolytes. Notably, an ultrahigh specific volumetric capacitance of 4255 F cm^?3 is achieved by the electrode tested in a1 m H₂SO₄ electrolyte, which represents the state‐of‐the‐art value reported to date for supercapacitor electrodes based on MXenes. The flexible supercapacitors constructed by the composite electrode, also demonstrate highly competitive energy and power densities: 459.75 mWh cm^?3 and 3.12 W cm^?3 for the asymmetrical one with a much widened potential window of 2 V in neutral electrolyte; 112.52 mWh cm^?3 and 1 W cm^?3 for the symmetrical configuration with an outstanding capacitance of 1265 F cm^?3 in acidic media. This work sheds new light on the fabrication of high‐performance supercapacitor electrodes with functionalities in different electrolyte media and various device configurations.     

Facile Synthesis of 3D MnO2–Graphene and Carbon Nanotube–Graphene Composite Networks for High‐Performance,Flexible, All‐Solid‐State Asymmetric Supercapacitors

The integration of graphene nanosheets on the macroscopic level using a self‐assembly method has been recognized as one of the most effective strategies to realize the practical applications of graphene materials. Here, a facile and scalable method is developed to synthesis two types of graphene‐based networks, manganese dioxide (MnO₂)–graphene foam and carbon nanotube (CNT)–graphene foam, by solution casting and subsequent electrochemical methods. Their practical applications in flexible all‐solid‐state asymmetric supercapacitors are explored. The proposed method facilitates the structural integration of graphene foam and the electroactive material and offers several advantages including simplicity, efficiency, low‐temperature, and low‐cost. The as‐prepared MnO₂–graphene and CNT–graphene electrodes exhibit high specific capacitances and rate capability. By using polymer gel electrolytes, a flexible all‐solid‐state asymmetric supercapacitor was synthesized with MnO₂–graphene foam as the positive electrode and CNT‐graphene as the negative electrode. The asymmetric supercapacitors can be cycled reversibly in a high‐voltage region of 0 to 1.8 V and exhibit high energy density, remarkable rate capability, reasonable cycling performance, and excellent flexibility.     

High Performance,Flexible, Solid‐State Supercapacitors Based on a Renewable and Biodegradable Mesoporous Cellulose Membrane

A flexible, transparent, and renewable mesoporous cellulose membrane (mCel‐membrane) featuring uniform mesopores of ≈24.7 nm and high porosity of 71.78% is prepared via a facile and scalable solution‐phase inversion process. KOH‐saturated mCel‐membrane as a polymer electrolyte demonstrates a high electrolyte retention of 451.2 wt%, a high ionic conductivity of 0.325 S cm^?1, and excellent mechanical flexibility and robustness. A solid‐state electric double layer capacitor (EDLC) using activated carbon as electrodes, the KOH‐saturated mCel‐membrane as a polymer electrolyte exhibits a high capacitance of 110 F g^?1 at 1.0 A g^?1, and long cycling life of 10 000 cycles with 84.7% capacitance retention. Moreover, a highly integrated planar‐type micro‐supercapacitor (MSC) can be facilely fabricated by directly depositing the electrode materials on the mCel‐membrane‐based polymer electrolyte without using complicated devices. The resulting MSC exhibits a high areal capacitance of 153.34 mF cm^?2 and volumetric capacitance of 191.66 F cm^?3 at 10 mV s^?1, representing one of the highest values among all carbon‐based MSC devices. These findings suggest that the developed renewable, flexible, mesoporous cellulose membrane holds great promise in the practical applications of flexible, solid‐state, portable energy storage devices that are not limited to supercapacitors.     

Integrated Conductive Hybrid Architecture of Metal–Organic Framework Nanowire Array on Polypyrrole Membrane for All‐Solid‐State Flexible Supercapacitors

Metal–organic frameworks (MOFs) with intrinsically porous structures are promising candidates for energy storage, however, their low electrical conductivity limits their electrochemical energy storage applications. Herein, the hybrid architecture of intrinsically conductive Cu‐MOF nanowire arrays on self‐supported polypyrrole (PPy) membrane is reported for integrated flexible supercapacitor (SC) electrodes without any inactive additives, binders, or substrates involved. The conductive Cu‐MOFs nanowire arrays afford high conductivity and a sufficiently active surface area for the accessibility of electrolyte, whereas the PPy membrane provides decent mechanical flexibility, efficient charge transfer skeleton, and extra capacitance. The all‐solid‐state flexible SC using integrated hybrid electrode demonstrates an exceptional areal capacitance of 252.1 mF cm^?2, an energy density of 22.4 µWh cm^?2, and a power density of 1.1 mW cm^?2, accompanied by an excellent cycle capability and mechanical flexibility over a wide range of working temperatures. This work not only presents a robust and flexible electrode for wide temperature range operating SC but also offers valuable concepts with regards to designing MOF‐based hybrid materials for energy storage and conversion systems.     

Graphene–Cellulose Paper Flexible Supercapacitors

A simple and scalable method to fabricate graphene‐cellulose paper (GCP) membranes is reported; these membranes exhibit great advantages as freestanding and binder‐free electrodes for flexible supercapacitors. The GCP electrode consists of a unique three‐dimensional interwoven structure of graphene nanosheets and cellulose fibers and has excellent mechanical flexibility, good specific capacitance and power performance, and excellent cyclic stability. The electrical conductivity of the GCP membrane shows high stability with a decrease of only 6% after being bent 1000 times. This flexible GCP electrode has a high capacitance per geometric area of 81 mF cm^?2, which is equivalent to a gravimetric capacitance of 120 F g^?1 of graphene, and retains >99% capacitance over 5000 cycles. Several types of flexible GCP‐based polymer supercapacitors with various architectures are assembled to meet the power‐energy requirements of typical flexible or printable electronics. Under highly flexible conditions, the supercapacitors show a high capacitance per geometric area of 46 mF cm^?2 for the complete devices. All the results demonstrate that polymer supercapacitors made using GCP membranes are versatile and may be used for flexible and portable micropower devices.     

Free‐Standing 3D Nanoporous Duct‐Like and Hierarchical Nanoporous Graphene Films for Micron‐Level Flexible Solid‐State Asymmetric Supercapacitors

High energy density and power density within a limited volume of flexible solid‐state supercapacitors are highly desirable for practical applications. Here, free‐standing high‐quality 3D nanoporous duct‐like graphene (3D‐DG) films are fabricated with high flexibility and robustness as the backbones to deposit flower‐like MnO₂ nanosheets (3D‐DG@MnO₂). The 3D‐DG is the ideal support for the deposition of large amount of active materials because of its large surface area, appropriate pore structure, and negligible volume compared with other kinds of carbon backbones. Moreover, the 3D‐DG preserve the distinctive 2D coherent electronic properties of graphene, in which charge carriers move rapidly with a small resistance through the high‐quality and continuous chemical vapor deposition‐grown graphene building blocks, which results in a high rate performance. Marvelously, ultrathin (≈50 μm) flexible solid‐state asymmetric supercapacitors (ASCs) using 3D‐DG@MnO₂ as the positive electrode and 3D hierarchical nanoporous graphene films as the negative electrode display ultrahigh volumetric energy density (28.2 mW h cm^?3) and power density (55.7 W cm^?3) at 2.0 V. Furthermore, as‐prepared ASCs show high cycle stability clearly demonstrating their broad applications as power supplies in wearable electronic devices.     

Wearable High‐Performance Supercapacitors Based on Silver‐Sputtered Textiles with FeCo2S4–NiCo2S4 Composite Nanotube‐Built Multitripod Architectures as Advanced Flexible Electrodes

To achieve high‐performance wearable supercapacitors (SCs), a new class of flexible electrodes with favorable architectures allowing large porosity, high conductivity, and good mechanical stability is strongly needed. Here, this study reports the rational design and fabrication of a novel flexible electrode with nanotube‐built multitripod architectures of ternary metal sulfides' composites (FeCo₂S₄–NiCo₂S₄) on a silver‐sputtered textile cloth. Silver sputtering is applicable to almost all kinds of textiles, and S^2? concentration is optimized during sulfidation process to achieve such architectures and also a complete sulfidation assuring high conductivity. New insights into concentration‐dependent sulfidation mechanism are proposed. The additive‐free FeCo₂S₄–NiCo₂S₄ electrode shows a high specific capacitance of 1519 F g^?1 at 5 mA cm^?2 and superior rate capability (85.1% capacitance retention at 40 mA cm^?2). All‐solid‐state SCs employing these advanced electrodes deliver high energy density of 46 W h kg^?1 at 1070 W kg^?1 as well as achieve remarkable cycling stability retaining 92% of initial capacitance after 3000 cycles at 10 mA cm^?2, and outstanding reliability with no capacitance degradation under large twisting. These are attributed to the components' synergy assuring rich redox reactions, high conductivity as well as highly porous but robust architectures. An almost linear increase in capacitance with devices' area indicates possibility to meet various energy output requirements. This work provides a general, low‐cost route to wearable power sources.     

Large‐Scale Conductive Yarns Based on Twistable Korean Traditional Paper (Hanji) for Supercapacitor Applications: Toward High‐Performance Paper Supercapacitors

A simple and scalable method to fabricate a yarn‐type supercapacitor with a large specific capacitance without the aid of traditional pseudocapacitive electrode materials such as conducting polymers and metal oxides is reported. The yarn‐type supercapacitors are made from twisting reduced graphene oxide (rGO) or/and single‐walled carbon nanotubes (SWNTs)‐coated Korean traditional paper (KTP). The yarn‐type paper supercapacitor displays surprisingly enhanced electrochemical capacitance values, showing synergistic effect between rGO and SWNTs (500 times larger than performance of yarn‐type rGO‐coated paper supercapacitors). Coating rGO or/and SWNTs on KTP gives good morphology to the composite film, in which porosity increases and mean pore diameter decreases. The yarn‐type rGO/SWNT paper supercapacitor shows good mechanical strength, high flexibility, excellent electrochemical performance, and long‐life operation. The yarn‐type supercapacitor has an excellent electrochemical performance with a specific capacitance of 366 F g^?1 at scan rate of 25 mV s^?1 and high stability without any degradation in electrical performance up to 10 000 charge–discharge cycles. The average capacitance of rGO/SWNT@KTP yarn‐type supercapacitors is seven times higher than that of sheet‐type supercapacitors at scan rate of 500 mV s^?1. The lighting of a red light‐emitting diode (LED) is demonstrated by the yarn‐type paper supercapacitor without connecting supercapacitors in series.     

Boron Element Nanowires Electrode for Supercapacitors

The pursuit of new categories of active materials as electrodes of supercapacitors remains a great challenge. Herein, for the first time, elemental boron as a superior electrode material of supercapacitors is reported, which exhibits significantly high capacitances and excellent rate performance in all alkaline, neutral, and acidic electrolytes. Notably, boron nanowire‐carbon fiber cloth (BNWs‐CFC) electrodes achieve a capacitance up to 42.8 mF cm^?2 at a scan rate of 5 mV s^?1 and 60.2 mF cm^?2 at a current density of 0.2 mA cm^?2 in the acidic electrolyte. Moreover, in all these three kinds of electrolytes, BNWs‐CFC electrodes demonstrate a decent cycling stability with >80% capacitance retention after 8000 charging/discharging cycles. The Dominating energy storage mechanism of BNWs in the different electrolytes is analyzed by looking into the kinetics of the electrochemical process. Subsequently, the BNWs‐CFC electrode is used to fabricate a flexible solid‐state supercapacitor, which reveals a specific capacitance up to 22.73 mF cm^?2 and good mechanical performance after 1000 bending cycles. This study opens a new avenue to explore elemental boron‐based new nanomaterials for the application of energy storage with superior electrochemical performance.     

Fullerene‐Based In Situ Doping of N and Fe into a 3D Cross‐Like Hierarchical Carbon Composite for High‐Performance Supercapacitors

Fullerene‐based carbons are promising electrode materials for supercapacitors due to their unique carbon structures and tunable architectures at the molecular level. By introducing various functional groups with many elements on the fullerene cages, diverse in situ metal/nonmetal‐doped carbon materials with enhanced pseudocapacitances and/or double layer capacitances can be prepared. In the present work, a fullerene derivative, ferrocenylpyrrolidine C₆₀, containing nitrogen and iron, is chosen as the only precursor. A unique microstructure is fabricated by a liquid–liquid interfacial precipitation process. Subsequently, a facile, one‐step annealing of the microstructure at different temperatures is performed. A series of in situ N and Fe‐codoped laminated 3D hierarchical carbon composites in the shape of a cross are successfully synthesized. The as‐prepared N and Fe‐codoped carbon material treated at 700 °C exhibits a high specific capacitance of 505.4 F g^?1 at 0.1 A g^?1. To the best knowledge, this is the highest supercapacitor capacitance based on fullerene electrode materials. The use of a fullerene derivative as an in‐situ doped carbon for applications in energy storage opens a new avenue for developing future synthetic strategies to extend the repertoire of electrode materials with high performance.