Fe-Based Coordination Polymers as Battery-Type Electrodes in Semi-Solid-State Battery-Supercapacitor Hybrid Devices

Simultaneously Improving Energy Storage and Oxygen Evolution Reaction by Causing Regional Defects in MOF-on-MOF Derived Hollow Se-Doped CoP-Fe2P Heterojunctions

Doping heteroatoms into metal phosphides to modify their electronic structure is an effective method, but the incomplete exposure of active sites is its inherent drawback. In this experiment, both Se doping and P vacancies are simultaneously introduced into CoP-Fe2P (named CoFe-P-Se) to enhance the internal reactivity. Benefiting from the unique hollow porous structure derived from the MOF-on-MOF template, as well as the enhanced intrinsic activity achieved by P defects and Se doping, CoFe-P-Se exhibits a high specific capacitance of 8.41 F cm-2 at a current density of 2 mA cm-2 when used as a supercapacitor electrode. When assembled into a hybrid supercapacitor with activated carbon, the energy density reaches 0.488 mWh cm-2 at a power density of 1.534 mW cm-2, and the capacity retention after 5000 charge-discharge cycles is as high as 90.65%. As an oxygen evolution reaction (OER) electrode, the CoFe-P-Se electrode shows a low overpotential of only 230 mV at a current density of 10 mA cm-2 and 278 mV at 100 mA cm-2. Additionally, it exhibits excellent stability for over 50 h at a current density of 100 mA cm-2. The designed element doping and vacancy engineering in this work will provide an insight for constructing high-performance electrodes.

The Utilization of Metal-Organic Frameworks and Their Derivatives Composite in Supercapacitor Electrodes

Up to now, the mainstream adoption of renewable energy has brought about substantial transformations in the electricity and energy sector. This shift has garnered considerable attention within the scientific community. Supercapacitors, known for their exceptional performance metrics like good charge/discharge capability, strong power density, as well as extended cycle longevity, have gained widespread traction across various sectors, including transportation and aviation. Metal-organic frameworks (MOFs) with unique traits including adaptable structure, highly customizable synthetic methods, and high specific surface area, have emerged as strong candidates for electrode materials. For enhancing the performance, MOFs are commonly compounded with other conducting materials to increase capacitance. This paper provides a detailed analysis of various common preparation strategies and characteristics of MOFs. It summarizes the recent application of MOFs and their derivatives as supercapacitor electrodes alongside other carbon materials, metal compounds, and conductive polymers. Additionally, the challenges encountered by MOFs in the realm of supercapacitor applications are thoroughly discussed. Compared to previous reviews, the content of this paper is more comprehensive, offering readers a deeper understanding of the diverse applications of MOFs. Furthermore, it provides valuable suggestions and guidance for future progress and development in the field of MOFs.

Recent Trends in Supercapacitor Research: Sustainability in Energy and Materials

Supercapacitors (SCs) have emerged as critical components in applications ranging from transport to wearable electronics due to their rapid charge-discharge cycles, high power density, and reliability. This review offers an analysis of recent strides in supercapacitor research, emphasizing pivotal developments in sustainability, electrode materials, electrolytes, and 'smart SCs' designed for modern microelectronics with attributes such as flexibility, stretchability, and biocompatibility. Central to this discourse are two dominant electrode materials: carbon materials (CMs), primarily in electric double layer capacitors (EDLCs), and pseudocapacitive materials, involving oxides/hydroxides, chalcogenides, metal-organic frameworks, conductive polymers and metal nitrides such as MXene. Despite EDLCs' historical use, challenges such as low energy density persist, with heteroatom introduction into the carbon lattice seen as a solution. Concurrently, pseudocapacitive materials dominate recent studies, with efficiency enhancement strategies, such as the creation of hybrids based on different types of materials, surface structural engineering and doping, under exploration. Electrolyte innovation, especially the shift towards gel polymer electrolytes for flexible SCs, and the harmonization of electrode materials with SC designs are highlighted. Emphasis is given to smart SCs with novel attributes such as self-charging, self-healing, biocompatibility, and environmentally conscious designs. In summary, the article underscores the drive in sustainable supercapacitor research to achieve high energy and power density, steering towards SCs that are efficient and versatile and involving bioderived/biocompatible SC materials. This brief review is based on selected recent references, offering depth combined with an accessible overview of the SC landscape.

Controlling the electronic structure of Fe-MOF electrocatalyst for enhanced water splitting and urea oxidation: A plasma-assisted approach

The design of high-performance electrocatalysts for water splitting and urea oxidation reactions requires effective regulation of their electronic structure and electrochemical surface area (ECSA). In this study, we developed an in-situ grown Fe-MOF electrocatalyst on Fe foam (FF) by using a combination of easy hydrothermal synthesis and advanced plasma technology (Fe-MOF/FF). By varying the plasma treatment time, we could tailor the surface morphology and electronic structure of the Fe-MOF/FF microrods. Meanwhile, density functional theory (DFT) calculations investigated the catalytic mechanism, revealing that plasma-treated Fe-MOF/FF has a lower energy barrier for water splitting and H* adsorption during the HER process, and higher catalytic activity for UOR. Additionally, the electronic density of optimized Fe-MOF/FF is significantly expanded near the Fermi level. Remarkably, our catalysts achieved exceptional activity in both water splitting and urea electrolysis, requiring only 1.54 V and 1.472 V, respectively, at 10 mA cm-2, with excellent stability. Our findings highlight the potential of plasma technology as a powerful tool for developing multifunctional electrocatalysts for clean energy and industrial wastewater treatment applications.

Metal-Organic Frameworks Meet Polymers: From Synthesis Strategies to Healthcare Applications

Metal-organic frameworks (MOFs) have been at the forefront of nanotechnological research for the past decade owing to their high porosity, high surface area, diverse configurations, and controllable chemical structures. They are a rapidly developing class of nanomaterials that are predominantly applied in batteries, supercapacitors, electrocatalysis, photocatalysis, sensors, drug delivery, gas separation, adsorption, and storage. However, the limited functions and unsatisfactory performance of MOFs resulting from their low chemical and mechanical stability hamper further development. Hybridizing MOFs with polymers is an excellent solution to these problems, because polymers-which are soft, flexible, malleable, and processable-can induce unique properties in the hybrids based on those of the two disparate components while retaining their individuality. This review highlights recent advances in the preparation of MOF-polymer nanomaterials. Furthermore, several applications wherein the incorporation of polymers enhances the MOF performance are discussed, such as anticancer therapy, bacterial elimination, imaging, therapeutics, protection from oxidative stress and inflammation, and environmental remediation. Finally, insights from the focus of existing research and design principles for mitigating future challenges are presented.

Nonporous, conducting bimetallic coordination polymers with an advantageous electronic structure for boosted faradaic capacitance

Conductive coordination polymers (c-CPs) are promising electrode materials for supercapacitors (SCs) owing to their excellent conductivity, designable structures and dense redox sites. However, despite their high intrinsic density and outstanding electrical properties, nonporous c-CPs have largely been overlooked in SCs because of their low specific surface areas and deficient ion-diffusion channels. Herein, we demonstrate that the nonporous c-CPs Ag5BHT (BHT = benzenehexathiolate) and CuAg4BHT are both battery-type capacitor materials with high specific capacitances and a large potential window. Notably, nonporous CuAg4BHT with bimetallic bis(dithiolene) units exhibits superior specific capacitance (372 F g-1 at 0.5 A g-1) and better rate capability than isostructural Ag5BHT. Structural and electrochemical studies showed that the enhanced charge transfer between different metal sites is responsible for its outstanding capacitive performance. Additionally, the assembled CuAg4BHT//AC SC device displays a favorable energy density of 17.1 W h kg-1 at a power density of 446.1 W kg-1 and an excellent cycling stability (90% capacitance retention after 5000 cycles). This work demonstrates the potential applications of such nonporous redox-active c-CPs in SCs and highlights the roles of bimetallic redox sites in capacitive performance, which hold promise for the future development of c-CP-based energy storage technologies.

Preparation and Characterization of Physically Activated Carbon and Its Energetic Application for All-Solid-State Supercapacitors: A Case Study

Biomass-derived activated carbons have gained significant attention as electrode materials for supercapacitors (SCs) due to their renewability, low-cost, and ready availability. In this work, we have derived physically activated carbon from date seed biomass as symmetric electrodes and PVA/KOH has been used as a gel polymer electrolyte for all-solid-state SCs. Initially, the date seed biomass was carbonized at 600 °C (C-600) and then it was used to obtain physically activated carbon through CO₂ activation at 850 °C (C-850). The SEM and TEM images of C-850 displayed its porous, flaky, and multilayer type morphologies. The fabricated electrodes from C-850 with PVA/KOH electrolytes showed the best electrochemical performances in SCs (Lu et al. Energy Environ. Sci., 2014, 7, 2160) application. Cyclic voltammetry was performed from 5 to 100 mV s^-1, illustrating an electric double layer behavior. The C-850 electrode delivered a specific capacitance of 138.12 F g^-1 at 5 mV s^-1, whereas it retained 16 F g^-1 capacitance at 100 mV s^-1. Our assembled all-solid-state SCs exhibit an energy density of 9.6 Wh kg^-1 with a power density of 87.86 W kg^-1. The internal and charge transfer resistances of the assembled SCs were 0.54 and 17.86 Ω, respectively. These innovative findings provide a universal and KOH-free activation process for the synthesis of physically activated carbon for all solid-state SCs applications.

Recent Advances in Metal-Organic Frameworks (MOFs) and Their Composites for Non-Enzymatic Electrochemical Glucose Sensors

In recent years, with pressing needs such as diabetes management, the detection of glucose in various substrates has attracted unprecedented interest from researchers in academia and industry. As a relatively new glucose sensor, non-enzymatic target detection has the characteristics of high sensitivity, good stability and simple manufacturing process. However, it is urgent to explore novel materials with low cost, high stability and excellent performance to modify electrodes. Metal-organic frameworks (MOFs) and their composites have the advantages of large surface area, high porosity and high catalytic efficiency, which can be utilized as excellent materials for electrode modification of non-enzymatic electrochemical glucose sensors. However, MOFs and their composites still face various challenges and difficulties that limit their further commercialization. This review introduces the applications and the challenges of MOFs and their composites in non-enzymatic electrochemical glucose sensors. Finally, an outlook on the development of MOFs and their composites is also presented.

3D Printed Supercapacitor Exploiting PEDOT-Based Resin and Polymer Gel Electrolyte

Renewable energy-based technologies and increasing IoT (Internet of Things) objects population necessarily require proper energy storage devices to exist. In the view of customized and portable devices, Additive Manufacturing (AM) techniques offer the possibility to fabricate 2D to 3D features for functional applications. Among the different AM techniques extensively explored to produce energy storage devices, direct ink writing is one of the most investigated, despite the poor achievable resolution. Herein, we present the development and characterization of an innovative resin which can be employed in a micrometric precision stereolithography (SL) 3D printing process for the fabrication of a supercapacitor (SC). Poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, was mixed with poly(ethylene glycol) diacrylate (PEGDA), to get a printable and UV curable conductive composite material. The 3D printed electrodes were electrically and electrochemically investigated in an interdigitated device architecture. The electrical conductivity of the resin falls within the range of conductive polymers with 200 mS/cm and the 0.68 µWh/cm² printed device energy density falls within the literature range.

Insight into Electrochemical Performance of Nitrogen-Doped Carbon/NiCo-Alloy Active Nanocomposites

Nanocomposites containing Ni or Co or NiCo alloy and nitrogen-doped carbon with diverse ratios have been prepared and utilized as active elements in supercapacitors. The atomic contents of nitrogen, nickel, and cobalt have been adjusted by the supplement amount of Ni and Co salts. In virtue of the excellent surface groups and rich redox active sites, the NC/NiCo active materials exhibit superior electrochemical charge-storage performances. Among these as-prepared active electrode materials, the NC/NiCo1/1 electrode performs better than other bimetallic/carbon electrodes and pristine metal/carbon electrodes. Several characterization methods, kinetic analyses, and nitrogen-supplement strategies determine the specific reason for this phenomenon. As a result, the better performance can be ascribed to a combination of factors including the high surface area and nitrogen content, proper Co/Ni ratio, and relatively low average pore size. The NC/NiCo electrode delivers a maximum capacity of 300.5 C g^-1 and superior capacity retention of 92.30% after 3000 unceasing charge-discharge cycles. After assembling it into the battery-supercapacitor hybrid device, a high energy density of 26.6 Wh kg^-1 (at 412 W kg^-1 ) is achieved, comparable to the recent reports. Furthermore, this device can also power four light-emitting-diode (LED) demos, suggesting the potential practicability of these N-doped carbon compositing with bimetallic materials.

Advances of Electroactive Metal-Organic Frameworks

The preparation of electroactive metal-organic frameworks (MOFs) for applications of supercapacitors and batteries has received much attention and remarkable progress during the past few years. MOF-based materials including pristine MOFs, hybrid MOFs or MOF composites, and MOF derivatives are well designed by a combination of organic linkers (e.g., carboxylic acids, conjugated aromatic phenols/thiols, conjugated aromatic amines, and N-heterocyclic donors) and metal salts to construct predictable structures with appropriate properties. This review will focus on construction strategies of pristine MOFs and hybrid MOFs as anodes, cathodes, separators, and electrolytes in supercapacitors and batteries. Descriptions and discussions follow categories of electrochemical double-layer capacitors (EDLCs), pseudocapacitors (PSCs), and hybrid supercapacitors (HSCs) for supercapacitors. In contrast, Li-ion batteries (LIBs), Lithium-sulfur batteries (LSBs), Lithium-oxygen batteries (LOBs), Sodium-ion batteries (SIBs), Sodium-sulfur batteries (SSBs), Zinc-ion batteries (ZIBs), Zinc-air batteries (ZABs), Aluminum-sulfur batteries (ASBs), and others (e.g., LiSe, NiZn, H⁺ , alkaline, organic, and redox flow batteries) are categorized for batteries.

MOF-derived NiCo-LDH Nanocages on CuO Nanorod Arrays for Robust and High Energy Density Asymmetric Supercapacitors

Layered double hydroxide (LDH) is widely explored in supercapacitors on account of its high capacity, adjustable composition and easy synthesis process. Unfortunately, solitary LDH still has great limitations as an electrode material due to its shortcomings, such as poor conductivity and easy agglomeration. Herein, nanoflakes assembled NiCo-LDH hollow nanocages derived from a metal-organic framework (MOF) precursor are strung by CuO nanorods formed from etching and oxidation of copper foam (CF), forming hierarchical CuO@NiCo-LDH heterostructures. The as-synthesized CuO@NiCo-LDH/CF shows a large capacitance (5607 mF cm^-2 at 1 mA cm^-2 ), superior rate performance (88.3 % retention at 10 mA cm^-2 ) and impressive cycling durability (93.1 % capacitance is retained after 5000 cycles), which is significantly superior to control CuO/CF, CuO@ZIF-67/CF, NiCo-LDH/CF and Cu(OH)₂ @NiCo-LDH/CF electrodes. Besides, an asymmetrical supercapacitor consists of CuO@NiCo-LDH/CF and activated carbon displays a maximum energy density of 47.3 Wh kg^-1 , and its capacitance only declines by 6.8 % after 10000 cycles, demonstrating remarkable cycling durability. The advantages of highly conductive and robust CuO nanorods, MOF-derived hollow structure and the core-shell heterostructure contribute to the outstanding electrochemical performance. This synthesis strategy can be extended to design various core-shell heterostructures adopted in versatile electrochemical energy storage applications.

A three-dimensional Mn-based MOF as a high-performance supercapacitor electrode

Developing new high-performance electrode materials for improving the energy density of supercapacitors is an important task. Herein, a new three-dimensional (3D) metal-orgainc framework (MOF) [Mn(BGPD)(H₂O)₂] (Mn-BGPD; BGPD = N,N'-bis(glycinyl)pyromellitic diimide) was synthesized. When Mn-BGPD is used as the electrode material of supercapacitors, in a three-electrode setup, it shows an outstanding specific capacitance of 832.6 F g^-1 at a current density of 1 A g^-1. The asymmetrical supercapacitor of Mn-BGPD shows an attractive specific capacitance of 100 F g^-1 at 1 A g^-1, which corresponds to an excellent energy density of 35.5 W h kg^-1. Moreover, better cycling stability with a capacitance retention of 46.7% is also shown. The high electrochemical performance makes Mn-BGPD a very promising electrode material for supercapacitors.

Composites Filled with Metal Organic Frameworks and Their Derivatives: Recent Developments in Flame Retardants

Polymer matrix is vulnerable to fire hazards and needs to add flame retardants to enhance its performance and make its application scenarios more extensive. At this stage, it is more necessary to add multiple flame-retardant elements and build a multi-component synergistic system. Metal organic frameworks (MOFs) have been studied for nearly three decades since their introduction. MOFs are known for their structural advantages but have only been applied to flame-retardant polymers for a relatively short period of time. In this paper, we review the development of MOFs utilized as flame retardants and analyze the flame-retardant mechanisms in the gas phase and condensed phase from the original MOF materials, modified MOF composites, and MOF-derived composites as flame retardants, respectively. The effects of carbon-based materials, phosphorus-based materials, nitrogen-based materials, and biomass on the flame-retardant properties of polymers are discussed in the context of MOFs. The construction of MOF multi-structured flame retardants is also introduced, and a variety of MOF-based flame retardants with different morphologies are shown to broaden the ideas for subsequent research.

High-Rate Organic Cathode Constructed by Iron-Hexaazatrinaphthalene Tricarboxylic Acid Coordination Polymer for Li-Ion Batteries

The sluggish ion-transport in electrodes and low utilization of active materials are critical limitations of organic cathodes, which lead to the slow reaction dynamics and low specific capacity. In this study, the hierarchical tube is constructed by iron-hexaazatrinaphthalene tricarboxylic acid coordination polymer (Fe-HATNTA), using HATNTA as the self-engaged template to coordinate with Fe2+ ions. This Fe-HATNTA tube with hierarchical porous structure ensures the sufficient contact between electrolyte and active materials, shortens the diffusion distance, and provides more favorable transport pathways for ions. When employed as the cathode for rechargeable Li-ion batteries, Fe-HATNTA delivers a high specific capacity (244 mAh g-1 at 50 mA g-1 , 91% of theoretical capacity), excellent rate capability (128 mAh g-1 at 9 A g-1 ), and a long-term cycle life (73.9% retention over 3000 cycles at 5 A g-1 ). Moreover, the Li+ ions storage and conduction mechanisms are further disclosed by the ex situ and in situ characterizations, kinetic analyses, and theoretical calculations. This work is expected to boost further enthusiasm for developing the hierarchical structured metal-organic coordination polymers with superb ionic storage and transport as high-performance organic cathodes.

Tremella-like 2D Nickel-Copper Disulfide with Ultrahigh Capacity and Cyclic Retention for Hybrid Supercapacitors

Two-dimensional (2D) disulfides possess unique physical and chemical properties and are widely used in electronic and photoelectric devices. Tuning the composition and optimizing the structure of the disulfides are feasible approaches to designing target sulfides for hybrid supercapacitors. This work synthesizes the tremella-like nanosheet-connected (Cu_xNi_1-x)S₂ via solvothermal and sulfur-vapor vulcanization. The 2D (Cu_xNi_1-x)S₂ electrode performs a high reversible capacity (526.0 mA h g^-1 at 1 A g^-1), decent capacity retention (75.6%) at 10 A g^-1, and prolonged cyclic retention (94.4% over 15,000 cycles), which is higher than that of (Cu_xNi_1-x)O and monometallic sulfides of NiS₂ and CuS. The elevated electrochemical properties of (Cu_xNi_1-x)S₂ are attributed to the optimized composition with increased redox reaction, enlarged lattice distance, abundant active sites, and attractive electronic and ionic conductivity. Also, (Cu_xNi_1-x)S₂ and active carbon (AC) are assembled to form a hybrid supercapacitor (HSC). The (Cu_xNi_1-x)S₂//AC HSC demonstrates a maximum specific capacitance of 231.0 F g^-1 at 1 A g^-1 and a high energy density of 82.4 W h kg^-1 at a power density of 1.82 kW kg^-1. Outstanding cyclic retentions of 94.9 and 84.5% after 8000 and 10,000 cycles are also obtained. In conclusion, this result suggests a facile routine for preparing a novel 2D layer material of (Cu_xNi_1-x)S₂ with outstanding specific capacity and cycling performance for hybrid supercapacitors.

A new two-dimensional cadmium(II) coordination polymer based on Cd6(CHADC)6 clusters (H2CHADC is cyclohexane-1,2-dicarboxylic acid): synthesis, structure and properties

The highly effective recognition and detection of metal ions and anions in water has attracted much attention with respect to environmental safety. Herein, a novel Cd-based coordination polymer, poly[[4,4'-bis(2-methylimidazol-1-yl)biphenyl]bis(cyclohexane-1,2-dicarboxylato)dicadmium(II)], [Cd₂(C₈H₁₀O₄)₂(C₂₀H₁₈N₄)]_n or [Cd(CHADC)(4,4'-BMIBP)_0.5]_n, (I), has been synthesized employing cis-cyclohexane-1,2-dicarboxylic acid (H₂CHADC) and 4,4'-bis(2-methyl-1H-imidazol-1-yl)biphenyl (4,4'-BMIBP). Single-crystal X-ray analysis reveals that (I) presents a 6-connected hxl two-dimensional layer based on Cd₆(CHADC)₆ clusters with the point symbol (3⁶·4⁶·5³). Furthermore, (I) has been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and fluorescence spectroscopy, and exhibits good stability and excellent photoluminescence properties. Coordination polymer (I) was chosen as a fluorescent probe to sense different target analytes and shows an obvious selective recognition response to Fe³⁺ cations and Cr₂O₇^2-/CrO₄^2- anions through luminescence-quenching effects in aqueous solution. The sensing mechanism was investigated and showed that the detection mechanism was resonance energy transfer between (I) and the Fe³⁺, Cr₂O₇^2- and CrO₄^2- ions.

2D/2D Nanoarchitectured Nb2C/Ti3C2 MXene Heterointerface for High-Energy Supercapacitors with Sustainable Life Cycle

Layered 2D/2D heterointerface composites experience interesting properties that greatly stimulate the recent surge in the attention as robust supercapacitor electrode materials, especially the MXene-based 2D/2D heterointerface for its robust energy storage compatibility. This report unveils a synergistically in situ prepared 2D/2D Nb₂C/Ti₃C₂ MXene (NCTC) heterointerface nanoarchitecture by facile one-pot chemical etching. The methodology adopted enables the interconnected and simultaneous growth of MXenes exposing and retaining their active surfaces for enhanced ion diffusion pathways, charge storage dynamics, microstructural stability, and a noticeable potential window. Henceforth, the in situ developed NCTC heterointerface electrode delivered an excellent specific capacitance of 584 F/g at 2 A/g with a commendable energy density of 38.5 W h/kg in MXene supercapacitors owing to the augmented surface- and redox-based charge storage at the interface. Finally, the developed all-solid-state system demonstrated a superior cycling retention of 98% capacitance after 50,000 cycles. These superlative results encourage the exploration of such prospective 2D/2D heterointerfaces with intriguing charge storage and microstructural attributes for designing next-generation energy storage systems.

All Transition Metal Selenide Composed High-Energy Solid-State Hybrid Supercapacitor

Transition metal selenides (TMSs) have enthused snowballing research and industrial attention due to their exclusive conductivity and redox activity features, holding them as great candidates for emerging electrochemical devices. However, the real-life utility of TMSs remains challenging owing to their convoluted synthesis process. Herein, a versatile in situ approach to design nanostructured TMSs for high-energy solid-state hybrid supercapacitors (HSCs) is demonstrated. Initially, the rose-nanopetal-like NiSe@Cu₂ Se (NiCuSe) positive electrode and FeSe nanoparticles negative electrode are directly anchored on Cu foam via in situ conversion reactions. The complementary potential windows of NiCuSe and FeSe electrodes in aqueous electrolytes associated with the excellent electrical conductivity results in superior electrochemical features. The solid-state HSCs cell manages to work in a high voltage range of 0-1.6 V, delivers a high specific energy density of 87.6 Wh kg^-1 at a specific power density of 914.3 W kg^-1 and excellent cycle lifetime (91.3% over 10 000 cycles). The innovative insights and electrode design for high conductivity holds great pledge in inspiring material synthesis strategies. This work offers a feasible route to develop high-energy battery-type electrodes for next-generation hybrid energy storage systems.

Stereolithography-Derived Three-Dimensional Pyrolytic Carbon/Mn3O4 Nanostructures for Free-Standing Hybrid Supercapacitor Electrodes

The development of permeable three-dimensional (3D) macroporous carbon architectures loaded with active pseudocapacitive nanomaterials offers hybrid supercapacitor (SC) materials with higher energy density, shortened diffusion length for ions, and higher charge-discharge rate capability and thereby is highly relevant for electrical energy storage (EES). Herein, structurally complex and tailorable 3D pyrolytic carbon/Mn₃O₄ hybrid SC electrode materials are synthesized through the self-assembly of MnO₂ nanoflakes and nanoflowers onto the surface of stereolithography 3D-printed architectures via a facile wet chemical deposition route, followed by a single thermal treatment. Thermal annealing of the MnO₂ nanostructures concurrent with carbonization of the polymer precursor leads to the formation of a 3D hybrid SC electrode material with unique structural integrity and uniformity. The microstructural and chemical characterization of the hybrid electrode reveals the predominant formation of crystalline hausmannite-Mn₃O₄ after the pyrolysis/annealing process, which is a favorable pseudocapacitive material for EES. With the combination of the 3D free-standing carbon architecture and self-assembled binder-free Mn₃O₄ nanostructures, electrochemical capacitive charge storage with very good rate capability, gravimetric and areal capacitances (186 F g^-1 and 968 mF cm^-2, respectively), and a long lifespan (>92% after 5000 cycles) is demonstrated. It is worth noting that the gravimetric capacitance value is obtained by considering the full mass of the electrode including the carbon current collector. When only the mass of the pseudocapacitive nanomaterial is considered, a capacitance value of 457 F g^-1 is achieved, which is comparable to state-of-the-art Mn₃O₄-based SC electrode materials.