3D Interdigital Au/MnO2/Au Stacked Hybrid Electrodes for On‐Chip Microsupercapacitors

On‐chip microsupercapacitors (MSCs) have application in powering microelectronic devices. Most of previous MSCs are made from carbon materials, which have high power but low energy density. In this work, 3D interdigital Au/MnO₂/Au stacked MSCs have been fabricated based on laser printed flexible templates. This vertical‐stacked electrode configuration can effectively increase the contact area between MnO₂ active layer and Au conductive layer, and thus improve the electron transport and electrolyte ion diffusion, resulting in enhanced pseudocapacitive performance of MnO₂. The stacked electrode can achieve an areal capacitance up to 11.9 mF cm^?2. Flexible and all‐solid‐state MSCs are assembled based on the sandwich hybrid electrodes and PVA/LiClO₄ gel electrolyte and show outstanding high‐rate capacity and mechanical flexibility. The laser printing technique in this work combined with the physical sputtering and electrodeposition allows fabrication of MSC array with random sizes and patterns, making them promising power sources for small‐scale flexible microelectronic energy storage systems (e.g., next‐generation smart phones).     

Facile synthesis of graphene@NiMoO<Subscript>4</Subscript> nanosheet arrays on Ni foam for a high-performance asymmetric supercapacitor

Honeycomb-like NiMoO₄ with nanosheet arrays is grown on reduced graphene oxide, which is supported on Ni foam having successfully fabricated by a simple hydrothermal treatment followed by a calcined process. In the as-synthesized Ni foam@reduced graphene oxide@NiMoO₄, Ni foam served as “skeleton” to support reduced graphene oxide and reduced graphene oxide directly grown on Ni foam served as the “skin” to provide high passway of electrons and ions, which simultaneously accommodated the volume change during the process of charge–discharge and NiMoO₄ acted as active substance to provide high areal capacitance. It shows a high areal capacitance of 2165.9 mF cm^?2 at a current density of 1 mA cm^?2 and long cycle stability with 93.8% capacitance retained over 1000 charge–discharge cycles. Moreover, an asymmetric supercapacitor has been constructed by using Ni foam@reduced graphene oxide and Ni foam@reduced graphene oxide@NiMoO₄ as negative and positive electrodes. The energy density of this asymmetric supercapacitor is 0.579 mWh cm^?2, and it retains 93.1% capacitance over charge–discharge 5000 cycles. Therefore, it reveals great promise for practical applications in energy storage devices.     

Zn‐Ion Hybrid Micro‐Supercapacitors with Ultrahigh Areal Energy Density and Long‐Term Durability

On‐chip micro‐supercapacitors (MSCs), as promising power candidates for microdevices, typically exhibit high power density, large charge/discharge rates, and long cycling lifetimes. However, as for most reported MSCs, the unsatisfactory areal energy density (<10 µWh cm^?2) still hinders their practical applications. Herein, a new‐type Zn‐ion hybrid MSC with ultrahigh areal energy density and long‐term durability is demonstrated. Benefiting from fast ion adsorption/desorption on the capacitor‐type activated‐carbon cathode and reversible Zn stripping/plating on the battery‐type electrodeposited Zn‐nanosheet anode, the fabricated Zn‐ion hybrid MSCs exhibit remarkable areal capacitance of 1297 mF cm^?2 at 0.16 mA cm^?2 (259.4 F g^?1 at a current density of 0.05 A g^?1), landmark areal energy density (115.4 µWh cm^?2 at 0.16 mW cm^?2), and a superb cycling stability without noticeable decay after 10 000 cycles. This work will inspire the fabrication and development of new high‐performance microenergy devices based on novel device design.     

Direct Laser‐Patterned Micro‐Supercapacitors from Paintable MoS2 Films

Micrometer‐sized electrochemical capacitors have recently attracted attention due to their possible applications in micro‐electronic devices. Here, a new approach to large‐scale fabrication of high‐capacitance, two‐dimensional MoS₂ film‐based micro‐supercapacitors is demonstrated via simple and low‐cost spray painting of MoS₂ nanosheets on Si/SiO₂ chip and subsequent laser patterning. The obtained micro‐supercapacitors are well defined by ten interdigitated electrodes (five electrodes per polarity) with 4.5 mm length, 820 μm wide for each electrode, 200 μm spacing between two electrodes and the thickness of electrode is ～0.45 μm. The optimum MoS₂‐based micro‐supercapacitor exhibits excellent electrochemical performance for energy storage with aqueous electrolytes, with a high area capacitance of 8 mF cm^?2 (volumetric capacitance of 178 F cm^?3) and excellent cyclic performance, superior to reported graphene‐based micro‐supercapacitors. This strategy could provide a good opportunity to develop various micro‐/nanosized energy storage devices to satisfy the requirements of portable, flexible, and transparent micro‐electronic devices.     

Zinc‐Tiered Synthesis of 3D Graphene for Monolithic Electrodes

A high‐surface‐area conductive cellular carbon monolith is highly desired as the optimal electrode for achieving high energy, power, and lifetime in electrochemical energy storage. 3D graphene can be regarded as a first‐ranking member of cellular carbons with the pore‐wall thickness down to mono/few‐atomic layers. Current 3D graphenes, derived from either gelation or pyrolysis routes, still suffer from low surface area, conductivity, stability, and/or yield, being subjected to methodological inadequacies including patchy assembly, wet processing, and weak controllability. Herein, a strategy of zinc‐assisted solid‐state pyrolysis to produce a superior 3D graphene is established. Zinc unprecedentedly impregnates and delaminates a solid (“nonhollow”) char into multiple membranes, which eliminates the morphological impurities ever‐present in the previous pyrolyses using solid‐state carbon precursors. Zinc also catalyzes the carbonization and graphitization, and its in situ thermal extraction and recycling enables the scaled‐up production. The created 3D graphene network consists integrally of morphologically and chemically pure graphene membranes. It possesses unrivaled surface area, outstanding stability, and conductivity both in air and electrolyte, exceeding preexisting 3D graphenes. The advanced 3D graphene thus equips a porous monolithic electrode with unparalleled energy density, power density, and lifetime in electric‐double‐layer capacitive devices.     

Fabrication of a 3D Hierarchical Sandwich Co9S8/α‐MnS@N–C@MoS2 Nanowire Architectures as Advanced Electrode Material for High Performance Hybrid Supercapacitors

Supercapacitors suffer from lack of energy density and impulse the energy density limit, so a new class of hybrid electrode materials with promising architectures is strongly desirable. Here, the rational design of a 3D hierarchical sandwich Co₉S₈/α‐MnS@N–C@MoS₂ nanowire architecture is achieved during the hydrothermal sulphurization reaction by the conversion of binary mesoporous metal oxide core to corresponding individual metal sulphides core along with the formation of outer metal sulphide shell at the same time. Benefiting from the 3D hierarchical sandwich architecture, Co₉S₈/α‐MnS@N–C@MoS₂ electrode exhibits enhanced electrochemical performance with high specific capacity/capacitance of 306 mA h g^?1/1938 F g^?1 at 1 A g^?1, and excellent cycling stability with a specific capacity retention of 86.9% after 10 000 cycles at 10 A g^?1. Moreover, the fabricated asymmetric supercapacitor device using Co₉S₈/α‐MnS@N–C@MoS₂ as the positive electrode and nitrogen doped graphene as the negative electrode demonstrates high energy density of 64.2 Wh kg^?1 at 729.2 W kg^?1, and a promising energy density of 23.5 Wh kg^?1 is still attained at a high power density of 11 300 W kg^?1. The hybrid electrode with 3D hierarchical sandwich architecture promotes enhanced energy density with excellent cyclic stability for energy storage.     

Direct Laser Writing of Graphene Made from Chemical Vapor Deposition for Flexible,Integratable Micro‐Supercapacitors with Ultrahigh Power Output

High‐performance yet flexible micro‐supercapacitors (MSCs) hold great promise as miniaturized power sources for increasing demand of integrated electronic devices. Herein, this study demonstrates a scalable fabrication of multilayered graphene‐based MSCs (MG‐MSCs), by direct laser writing (DLW) of stacked graphene films made from industry‐scale chemical vapor deposition (CVD). Combining the dry transfer of multilayered CVD graphene films, DLW allows a highly efficient fabrication of large‐areal MSCs with exceptional flexibility, diverse planar geometry, and capability of customer‐designed integration. The MG‐MSCs exhibit simultaneously ultrahigh energy density of 23 mWh cm^?3 and power density of 1860 W cm^?3 in an ionogel electrolyte. Notably, such MG‐MSCs demonstrate an outstanding flexible alternating current line‐filtering performance in poly(vinyl alcohol) (PVA)/H₂SO₄ hydrogel electrolyte, indicated by a phase angle of ?76.2° at 120 Hz and a resistance–capacitance constant of 0.54 ms, due to the efficient ion transport coupled with the excellent electric conductance of the planar MG microelectrodes. MG–polyaniline (MG‐PANI) hybrid MSCs fabricated by DLW of MG‐PANI hybrid films show an optimized capacitance of 3.8 mF cm^?2 in PVA/H₂SO₄ hydrogel electrolyte; an integrated device comprising MG‐MSCs line filtering, MG‐PANI MSCs, and pressure/gas sensors is demonstrated.     

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.     

Synthesis of P‐Doped and NiCo‐Hybridized Graphene‐Based Fibers for Flexible Asymmetrical Solid‐State Micro‐Energy Storage Device

Fiber supercapacitors (FSCs) are promising energy storage devices in portable and wearable smart electronics. Currently, a major challenge for FSCs is simultaneously achieving high volumetric energy and power densities. Herein, the microscale fiber electrode is designed by using carbon fibers as substrates and capillary channels as microreactors to space‐confined hydrothermal assembling. As P‐doped graphene oxide/carbon fiber (PGO/CF) and NiCo₂O₄‐based graphene oxide/carbon fiber (NCGO/CF) electrodes are successfully prepared, their unique hybrid structures exhibit a satisfactory electrochemical performance. An all‐solid‐state PGO/CF//NCGO/CF flexible asymmetric fiber supercapacitor (AFSC) based on the PGO/CF as the negative electrode, NCGO/CF hybrid electrode as the positive electrode, and poly(vinyl alcohol)/potassium hydroxide as the electrolyte is successfully assembled. The AFSC device delivers a higher volumetric energy density of 36.77 mW h cm^?3 at a power density of 142.5 mW cm^?3. In addition, a double reference electrode system is adopted to analyze and reduce the IR drop, as well as effectively matching negative and positive electrodes, which is conducive for the optimization and improvement of energy density. For the AFSC device, its better flexibility and electrochemical properties create a promising potential for high‐performance micro‐supercapacitors. Furthermore, the introduction of the double reference electrode system provides an interesting method for the study on the electrochemical performances of two‐electrode systems.     

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.     

The Road Towards Planar Microbatteries and Micro‐Supercapacitors: From 2D to 3D Device Geometries

The rapid development and further modularization of miniaturized and self‐powered electronic systems have substantially stimulated the urgent demand for microscale electrochemical energy storage devices, e.g., microbatteries (MBs) and micro‐supercapacitors (MSCs). Recently, planar MBs and MSCs, composed of isolated thin‐film microelectrodes with extremely short ionic diffusion path and free of separator on a single substrate, have become particularly attractive because they can be directly integrated with microelectronic devices on the same side of one single substrate to act as a standalone microsized power source or complement miniaturized energy‐harvesting units. The development of and recent advances in planar MBs and MSCs from the fundamentals and design principle to the fabrication methods of 2D and 3D planar microdevices in both in‐plane and stacked geometries are highlighted. Additonally, a comprehensive analysis of the primary aspects that eventually affect the performance metrics of microscale energy storage devices, such as electrode materials, electrolyte, device architecture, and microfabrication techniques are presented. The technical challenges and prospective solutions for high‐energy‐density planar MBs and MSCs with multifunctionalities are proposed.     

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.     

Carbon‐MEMS‐Based Alternating Stacked MoS2@rGO‐CNT Micro‐Supercapacitor with High Capacitance and Energy Density

A novel process to fabricate a carbon‐microelectromechanical‐system‐based alternating stacked MoS₂@rGO–carbon‐nanotube (CNT) micro‐supercapacitor (MSC) is reported. The MSC is fabricated by successively repeated spin‐coating of MoS₂@rGO/photoresist and CNT/photoresist composites twice, followed by photoetching, developing, and pyrolysis. MoS₂@rGO and CNTs are embedded in the carbon microelectrodes, which cooperatively enhance the performance of the MSC. The fabricated MSC exhibits a high areal capacitance of 13.7 mF cm^?2 and an energy density of 1.9 µWh cm^?2 (5.6 mWh cm^?3), which exceed many reported carbon‐ and MoS₂‐based MSCs. The MSC also retains 68% of capacitance at a current density of 2 mA cm^?2 (5.9 A cm^?3) and an outstanding cycling performance (96.6% after 10 000 cycles, at a scan rate of 1 V s^?1). Compared with other MSCs, the MSC in this study is fabricated by a low‐cost and facile process, and it achieves an excellent and stable electrochemical performance. This approach could be highly promising for applications in integration of micro/nanostructures into microdevices/systems.     

A Laser-Processed Carbon-Titanium Carbide Heterostructure Electrode for High-Frequency Micro-Supercapacitors

Micro-supercapacitors (MSCs) are an important energy storage component for future miniaturized electronic systems, yet their key performance indexes such as high-frequency response, energy density, and cycle life still have a large room to be improved. Herein, a laser-processed carbon-titanium carbide heterostructure (LCTH) electrode is demonstrated, which can excellently address the above key challenges by employing a unique one-step laser-processing fabrication method. Different from the other reported electrode structures, this LCTH electrode shows a heterogeneous structure, featuring the carbon nanofoam layer which provides extremely short ion transport channels and abundant electrochemical active sites, and the underlying titanium carbide layer which can provide excellent electron conductivity and contribute to the pseudo-capacitance. The assembled symmetric supercapacitor can stably work at the voltage window of 3.5 V at an ultra-high frequency of approximately 1121.3 Hz, exhibiting an ultra-high areal specific energy density of 721 µFV² cm⁻² at 120 Hz and a cycle life of 140 000 cycles with capacitance retention of 100.95%, which is superior to most reported MSCs. The as-fabricated MSC is compatible with the contemporary embedded electronic component fabrication processes, which shows significant advantages in large-scale fabrication and system integration, demonstrating a broad prospect for future system-in-package applications.     

Ultra‐light Hierarchical Graphene Electrode for Binder‐Free Supercapacitors and Lithium‐Ion Battery Anodes

A mild and environmental‐friendly method is developed for fabricating a 3D interconnected graphene electrode with large‐scale continuity. Such material has interlayer pores between reduced graphene oxide nanosheets and in‐plane pores. Hence, a specific surface area up to 835 m² g⁻¹ and a high powder conductivity up to 400 S m⁻¹ are achieved. For electrochemical applications, the interlayer pores can serve as “ion‐buffering reservoirs” while in‐plane ones act as “channels” for shortening the mass cross‐plane diffusion length, reducing the ion response time, and prevent the interlayer restacking. As binder‐free supercapacitor electrode, it delivers a specific capacitance up to 169 F g⁻¹ with surface‐normalized capacitance close to 21 μF cm⁻² (intrinsic capacitance) and power density up to 7.5 kW kg⁻¹, in 6 m KOH aqueous electrolyte. In the case of lithium‐ion battery anode, it shows remarkable advantages in terms of the initiate reversible Coulombic efficiency (61.3%), high specific capacity (932 mAh g⁻¹ at 100 mA g⁻¹), and robust long‐term retention (93.5% after 600 cycles at 2000 mAh g⁻¹).     

Photoresponsive Smart Coloration Electrochromic Supercapacitor

Electrochromic devices have been widely adopted in energy saving applications by taking advantage of the electrode coloration, but it is critical to develop a new electrochromic device that can undergo smart coloration and can have a wide spectrum in transmittance in response to input light intensity while also functioning as a rechargeable energy storage system. In this study, a photoresponsive electrochromic supercapacitor based on cellulose‐nanofiber/Ag‐nanowire/reduced‐graphene‐oxide/WO₃‐composite electrode that is capable of undergoing “smart” reversible coloration while simultaneously functioning as a reliable energy‐storage device is developed. The fabricated device exhibits a high coloration efficiency of 64.8 cm² C^?1 and electrochemical performance with specific capacitance of 406.0 F g^?1, energy/power densities of 40.6–47.8 Wh kg^?1 and 6.8–16.9 kW kg^?1. The electrochromic supercapacitor exhibits excellent cycle reliability, where 75.0% and 94.1% of its coloration efficiency and electrochemical performance is retained, respectively, beyond 10 000 charge–discharge cycles. Cyclic fatigue tests show that the developed device is mechanically durable and suitable for wearable electronics applications. The smart electrochromic supercapacitor system is then integrated with a solar sensor to enable photoresponsive coloration where the transmittance changes in response to varying light intensity.     

Low-Temperature Resistant Stretchable Micro-Supercapacitor Based on 3D Printed Octet-Truss Design

Recently, stretchable micro-supercapacitors (MSCs) that can be easily integrated into electronic devices have attracted research and industrial attentions. In this work, three-dimensional (3D) stretchable MSCs with an octet-truss electrode (OTE) design have been demonstrated by a rapid digital light processing (DLP) process. The 3D-printed electrode structure is beneficial for electrode-electrolyte interface formation and consequently increases the number of ions adsorbed on the electrode surface. The designed MSCs can achieve a high capacitance as ≈74.76 mF cm⁻³ under 1 mA cm⁻³ at room temperature even under a high mechanical deformation, and can achieve 19.53 mF cm⁻³ under 0.1 mA cm⁻³ at a low temperature (−30 °C). Moreover, finite element analysis (FEA) reveals the OTE structure provides 8 times more contact area per unit volume at the electrode-electrolyte interface compared to the traditional interdigital electrode (IDE). This work combines structural design and 3D printing techniques, which provides new insights into highly stretchable MSCs for next-generation electronic devices.     

Stacking‐Controlled Assembly of Cabbage‐Like Graphene Microsphere for Charge Storage Applications

Nanostructured graphene electrodes generally have a low density, which can limit the volumetric performance for energy storage devices. The liquid‐phase mild reduction process of graphene oxide sheets is combined with the continuous aerosol densification process to produce high‐density graphene agglomerates in the form of microspheres. The produced graphene assembly shows the cabbage‐like morphology with a high density of 0.75 g cm^?3. In spite of such high density, the cabbage‐like graphene microspheres have narrow‐ranged mesopores and a high surface area. The cabbage‐like graphene microsphere exhibits both high gravimetric and volumetric energy densities due to the optimized microstructure, which shows a high gravimetric capacitance of 177 F g^?1 and volumetric capacitance of 117 F cm^?3 in supercapacitors. As a cathode for lithium‐ion capacitors, the cabbage‐like graphene delivers a reversible capacity of ≈176 mAh g^?1. The stacking‐control approach provides a new pathway to control the microstructure of the graphene assembly and corresponding charge storage characteristics for energy storage applications.     

Solution-processed graphene/MnO2 nanostructured textiles for high-performance electrochemical capacitors

Large scale energy storage system with low cost, high power, and long cycle life is crucial for addressing the energy problem when connected with renewable energy production. To realize grid-scale applications of the energy storage devices, there remain several key issues including the development of low-cost, high-performance materials that are environmentally friendly and compatible with low-temperature and large-scale processing. In this report, we demonstrate that solution-exfoliated graphene nanosheets (～5 nm thickness) can be conformably coated from solution on three-dimensional, porous textiles support structures for high loading of active electrode materials and to facilitate the access of electrolytes to those materials. With further controlled electrodeposition of pseudocapacitive MnO(2) nanomaterials, the hybrid graphene/MnO(2)-based textile yields high-capacitance performance with specific capacitance up to 315 F/g achieved. Moreover, we have successfully fabricated asymmetric electrochemical capacitors with graphene/MnO(2)-textile as the positive electrode and single-walled carbon nanotubes (SWNTs)-textile as the negative electrode in an aqueous Na(2)SO(4) electrolyte solution. These devices exhibit promising characteristics with a maximum power density of 110 kW/kg, an energy density of 12.5 Wh/kg, and excellent cycling performance of ～95% capacitance retention over 5000 cycles. Such low-cost, high-performance energy textiles based on solution-processed graphene/MnO(2) hierarchical nanostructures offer great promise in large-scale energy storage device applications.     

Hierarchical 3D Cobalt‐Doped Fe3O4 Nanospheres@NG Hybrid as an Advanced Anode Material for High‐Performance Asymmetric Supercapacitors

Hierarchical nanostructure, high electrical conductivity, extraordinary specific surface area, and unique porous architecture are essential properties in energy storage and conversion studies. A new type of hierarchical 3D cobalt encapsulated Fe₃O₄ nanosphere is successfully developed on N‐graphene sheet (Co?Fe₃O₄ NS@NG) hybrid with unique nanostructure by simple, scalable, and efficient solvothermal technique. When applied as an electrode material for supercapacitors, hierarchical Co?Fe₃O₄ NS@NG hybrid shows an ultrahigh specific capacitance (775 F g^?1 at a current density of 1 A g^?1) with exceptional rate capability (475 F g^?1 at current density of 50 A g^?1), and admirable cycling performance (97.1% capacitance retention after 10 000 cycles). Furthermore, the fabricated Co?Fe₃O₄ NS@NG//CoMnO₃@NG asymmetric supercapacitor (ASC) device exhibits a high energy density of 89.1 Wh kg^?1 at power density of 0.901 kW kg^?1, and outstanding cycling performance (89.3% capacitance retention after 10 000 cycles). Such eminent electrochemical properties of the Co?Fe₃O₄ NS@NG are due to the high electrical conductivity, ultrahigh surface area, and unique porous architecture. This research first proposes hierarchical Co?Fe₃O₄ NS@NG hybrid as an ultrafast charge?discharge anode material for the ASC device, that holds great potential for the development of high‐performance energy storage devices.