Electrospinning Synthesis of Self-Standing Cobalt/Nanocarbon Hybrid Membrane for Long-Life Rechargeable Zinc–Air Batteries

Integrating high-efficiency oxygen electrocatalyst directly into air electrodes is vital for zinc–air batteries to achieve higher electrochemical performance. Herein, a self-standing membrane composed of hierarchical cobalt/nanocarbon nanofibers is fabricated by the electrospinning technique. This hybrid membrane can be directly employed as the bifunctional air electrode in zinc–air batteries and can achieve a high peak power density of 304 mW cm⁻² with a long service life of 1500 h at 5 mA cm⁻². Its assembled solid-state zinc–air battery also delivers a promising power density of 176 mW cm⁻² with decent flexibility. The impressive rechargeable battery performance would be attributed to the self-standing membrane architecture integrated by oxygen electrocatalysts with abundant cobalt–nitrogen–carbon active species in the hierarchical electrode. This study may provide effective electrospinning solutions in integrating efficient electrocatalyst and electrode for energy storage and conversion technologies.     

Efficient Water Splitting System Enabled by Multifunctional Platinum-Free Electrocatalysts

Tremendous research efforts have been focused on the development of a water splitting system (WSS) to harvest hydrogen fuels, but currently available WSSs are complicated and cost-ineffective mainly due to the applications of noble platinum or different electrocatalysts. Herein, a novel WSS comprising electricity generation from solar panels, electricity storage in rechargeable zinc–air batteries (ZABs), and water splitting in electrolyzers, enabled by hybrid cobalt nanoparticles/N-doped carbon embellished on carbon cloth (Co–NC@CC) as multifunctional platinum-free electrocatalysts is reported. Consequently, the Co–NC@CC electrode presents excellent trifunctional electrocatalytic activity with an onset potential of 0.94 V for oxygen reduction reaction, and an overpotential of 240 and 73 mV to achieve a current density of 10 mA cm⁻² for oxygen and hydrogen evolution reactions, respectively. For a proof-of-concept application, a rechargeable ZAB assembled from the high-performance Co–NC@CC air cathode exhibits a high open circuit potential of 1.63 V and a superior energy density of 1051 Wh kg⁻¹_Zn. Furthermore, an overall water splitting electrolyzer constructed by the symmetrical Co–NC@CC electrodes delivers a current density of 10 mA cm⁻² at a low cell voltage of 1.57 V. Such a solar-powered WSS can harvest hydrogen day and night, demonstrating a potential for application in sustainable renewable energy.     

A Cost‐Effective Mixed Matrix Polyethylene Porous Membrane for Long‐Cycle High Power Density Alkaline Zinc‐Based Flow Batteries

Alkaline zinc‐based flow batteries (ZFBs) have received considerable interest for renewable energy storage due to their attractive features of low cost and high energy density. However, a membrane with high stability, high selectivity, and high ion conductivity is in urgent need. Herein, an economical mixed matrix membrane with highly anti‐alkali microporous hollow spheres (denoted as DM‐HM) is developed in this work. With excellent chemical and mechanical stability, DM‐HM can achieve a high area capacity of 100 mA h cm^?2 for carbon felt (CF)||Zn@CF symmetrical flow battery, and thereby exhibits 500 stable cycles with a coulombic efficiency of 98.6% and an energy efficiency of 88.3% at 80 mA cm^?2 for alkaline zinc–iron flow battery. Additionally, with 44 wt% of hollow spheres inside matrix, DM‐HM can dramatically shorten the ion transport pathway and results in a very high power density battery. A kilowatt stack assembled with DM‐HM shows a very impressive performance, further confirming the practicability of this scalable mixed matrix membrane for alkaline ZFBs.     

Multifunctional Carbon Felt Electrode with N-Rich Defects Enables a Long-Cycle Zinc-Bromine Flow Battery with Ultrahigh Power Density

Zinc-bromine flow batteries (ZBFBs) are regarded as one of the most promising technologies for energy storage owing to high energy density and low cost. However, the sluggish reaction kinetics of Br₂/Br⁻ couples and zinc dendrite issue lead to low power density and poor cycle stability. Herein, a multifunctional carbon felt-based electrode (NTCF) with N-rich defects is fabricated for ZBFBs. The defects with abundant N-containing groups on carbon fibers of NTCF provide high catalytic activity on Br₂/Br⁻ reactions. Simultaneously, the lower energy barrier of N-rich defects to adsorb zinc atoms, and more deposition sites on NTCF induce more uniform zinc deposition. Thus, a ZBFB using NTCF as both the anode and cathode can stably operate at an unprecedentedly high current density of 180 mA cm⁻² with a coulombic efficiency of 97.25%. Moreover, a long cycle life of over 140 cycles with a coulombic efficiency of 98.93% for a Zn symmetric flow battery at 80 mA cm⁻² is achieved under a high areal capacity of 40 mAh cm⁻². This current density and areal capacity are by far the highest values ever reported for Zn symmetry flow batteries. Therefore, this work provides an available approach to improve the power density and cycle life of ZBFBs.     

Zinc Intercalated Lattice Expansion of Ultrafine Platinum–Nickel Oxygen Reduction Catalyst for PEMFC

Platinum (Pt)-based membrane electrode assembly (MEA) catalysts with high performance under operating proton exchange membrane fuel cells (PEMFCs) conditions are a prerequisite for practical applications. As indicated by theoretical calculations, lattice expansion in zinc (Zn)-intercalated Pt alloys can weaken the adsorption of oxygen intermediates, enabling strong electronic interaction for boosting MEA catalysis. To test this hypothesis, herein, a new class of carbon (C)-supported ultrafine Pt alloys with the assistance of Zn is explored. Detailed characterizations indicate that the introduction of Zn can reduce the particle size, and simultaneously intercalates into the Pt alloys, resulting in the lattice expansion for enhancing metallic state of Pt and lowering d-band center. This intercalation strategy can be extended to PtNi, PtCo, as well as Pt. As a result, the optimized Zn-PtNi/C exhibits superior MEA activity (937.6 mW cm⁻² of peak power density), much higher than those of corresponding PtNi/C (771.6 mW cm⁻²) and commercial Pt/C (700.7 mW cm⁻²) under the harsh operating fuel cell conditions. This work opens up a new avenue for creating high-performance PEMFC catalysts in terms of lattice engineering.     

In Situ Defect-Free Vertically Aligned Layered Double Hydroxide Composite Membrane for High Areal Capacity and Long-Cycle Zinc-Based Flow Battery

Rechargeable aqueous zinc-based flow batteries (ZFBs) are promising candidates for large scale energy storage devices. However, the challenges from zinc dendrites and limited areal capacity considerably impede their wide application. Here, an in situ vertical growth of layered double hydroxide membrane (LDH-G) is constructed to enable long-life ZFBs. Owing to the high hydroxide ion conductivity and ion selectivity nature of LDH nanosheets, specifically, the precise control of directional ion transport in vertical arrangement LDHs, a superior battery performance can be realized. Moreover, the defect-free LDHs layer serves as a buffer layer to enable a uniform Zn deposition, which effectively enhances the areal capacity of the battery. As a result, the designed membrane endows an alkaline zinc-iron flow battery with excellent rate performance and cycling stability, maintaining an energy efficiency of 80% at 260 mA cm⁻² for 800 cycles, which is the highest performance ever reported. Most importantly, the LDHs layer enables the battery for 1200 h long-cycle stability with a uniform Zn deposition and high areal capacity of 240 mAh cm⁻². This work realizes an in situ growth of 3D LDHs arrays on the polymer substrate, which provides a strategy toward high areal capacity and dendrite-free Zn deposition for ZFBs.     

Metallic Particles-Induced Surface Reconstruction Enabling Highly Durable Zinc Metal Anode

Aqueous zinc batteries usher in a renaissance due to their intrinsic security and cost effectiveness, bespeaking vast application foreground for large-scale energy storage system. However, uncontrolled dendrite growth along with hydrogen evolution severely restricts its reversibility and stability for practical application. Herein, the surface of Zn metal is reconstructed with metallic particles (In, Sn, In_0.2Sn_0.8) to diminish surface defects and regulate Zn deposition behavior. The alloyed In–Sn greatly activates the Zn surface for lower Zn adsorption energy barrier to expedite plating kinetics and confine Zn aggregation. Dense and uniform deposition of Zn on the reconstructed surface significantly prevents the Zn substrate from dendrites growth for catastrophic damage. Meanwhile, alloy layer embodies high hydrogen evolution overpotential, ensuring high plating and stripping efficiency for Zn anode. Consequently, In_0.2Sn_0.8 reconstructed surface realizes long-term lifespan up to 1800 h with low polarization (12 mV) at the condition of 1 mA cm⁻² and 1 mAh cm⁻². When paired with sodium vanadate (NVO) cathode, the full cell steady operates for a high-capacity retention of 94.0% after 5000 cycles at 5 A g⁻¹. This study provides new insights into the surface-defects dependent Zn deposition process and offers a guide for constructing stable surface for dendrite-free Zn growth.     

Advanced Zinc–Iodine Batteries with Ultrahigh Capacity and Superior Rate Performance Based on Reduced Graphene Oxide and Water-in-Salt Electrolyte

Aqueous rechargeable zinc–iodine batteries have received increasing attention in the field of portable electronics due to their high safety, low-cost, and great electrochemical performance. However, the insulated nature of iodine and the unrestricted shuttle effect of soluble triiodide seriously limit the lifespan and Coulombic efficiency (CE) of the batteries. Herein, a high-performance zinc–iodine energy storage system based on the hydrothermal reduced graphene oxide (rGO) and a high concentration zinc chloride water-in-salt electrolyte are promoted. The 3D microporous structures and outstanding electrical conductivity of rGO make it an excellent host for iodine, while the water-in-salt electrolyte effectively suppresses the shuttle effect of triiodide and improves the CE of the system. As a result, an ultra-high I₂ mass loading of 25.33 mg cm⁻² (loading ratio of 71.69 wt.%) is realized during the continuous charging/discharging process. The batteries deliver a high capacity of 6.5 mAh cm⁻² at 2 mA cm⁻² with a much-improved CE of 95% and a prominent rate performance with capacity of 1 mAh cm⁻² at 80 mA cm⁻². A stable long-term cycling performance is also achieved with capacity retention of 2 mAh cm⁻² after 2000 cycles at 50 mA cm⁻².     

A Semi-Liquid Electrode toward Stable Zn Powder Anode

Zn powder anode possesses great versatility compared to the Zn foil counterpart, but the rough surface with a high surface area aggravates the corrosion and dendrite growth. Herein, a dendrite-free and anti-corrosive semi-liquid Zn anode (SLA) is successfully fabricated based on Zn powder and a thickening agent. Benefiting from the rheological property, the unique anode effectively releases the stress induced by Zn plating, especially under high-current densities. Meanwhile, the dual-conductive medium, i.e., ionic and electronic, homogenizes the ion flux and allows the stripping/plating to occur within the entire anode. In a symmetric cell, the SLA anode exhibits stable electrochemical behavior with a prolonged lifespan at the current density of 5 mA cm⁻²/10 mA cm⁻² under the capacity of 5 mAh cm⁻²/10 mAh cm⁻². Improved durability of more than 5000 cycles is endowed when assembling an SLA anode with a vanadium-based cathode. This study provides an electrode rheology-based approach to overcome the stability challenge of powder anode for scale-up manufacturing.     

In Situ Induced Core–Shell Carbon-Encapsulated Amorphous Vanadium Oxide for Ultra-Long Cycle Life Aqueous Zinc-Ion Batteries

Inevitable dissolution in aqueous electrolytes, intrinsically low electrical conductivity, and sluggish reaction kinetics have significantly hampered the zinc storage performance of vanadium oxide-based cathode materials. Herein, core–shell N-doped carbon-encapsulated amorphous vanadium oxide arrays, prepared via a one-step nitridation process followed by in situ electrochemical induction, as a highly stable and efficient cathode material for aqueous zinc-ion batteries (AZIBs) are reported. In this design, the amorphous vanadium oxide core provides unobstructed ions diffusion routes and abundant active sites, while the N-doped carbon shell can ensure efficient electron transfer and greatly stabilize the vanadium oxide core. The assembled AZIBs exhibit remarkable discharge capacity (0.92 mAh cm⁻² at 0.5 mA cm⁻²), superior rate capability (0.51 mAh cm⁻² at 20 mA cm⁻²), and ultra-long cycling stability (≈100% capacity retention after 500 cycles at 0.5 mA cm⁻² and 97% capacity retention after 10 000 cycles at 20 mA cm⁻²). The working mechanism is further validated by in situ X-ray diffraction combined with ex situ tests. Moreover, the fabricated cathode is highly flexible, and the assembled quasi-solid-state AZIBs present stable electrochemical performance under large deformations. This work offers insights into the development of high-performance amorphous vanadium oxide-based cathodes for AZIBs.     

Dendrite-Free Reverse Lithium Deposition Induced by Ion Rectification Layer toward Superior Lithium Metal Batteries

Considerable endeavors are developed to suppress lithium (Li) dendrites and improve the cycling stability of Li metal batteries in order to promote their commercial application. Herein, continuous zinc (Zn) nanoparticles-assembled film with homogenous nanopores is proposed as a modified layer for separator via a scalable method. The in situ formed LiZn alloy film during initial Li plating can serve as a Li⁺ ion rectification and lithiophilic layer to regulate the nucleation and reverse deposition of Li. When applied in Li|LiFePO₄ full cells with traditional carbonate-based electrolyte, the modified separator enables outstanding cycling stability of up to 350 cycles without capacity loss at a large rate of 5 C (3.4 mA cm⁻²) and a remarkable reversible capacity of 144 mAh g⁻¹ after 120 cycles at a commercial mass loading as high as 19.72 mg cm⁻². The excellent electrochemical performances are ascribed to the dendrite-free reverse Li deposition induced by modified layer by means of its lithiophilic property for regulating homogeneous Li nucleation on the separator as well as its well-distributed nanopores for homogenizing Li⁺ ion flux and enhancing electrolyte wetting.     

Fabrication of Polyoxometalate Anchored Zinc Cobalt Sulfide Nanowires as a Remarkable Bifunctional Electrocatalyst for Overall Water Splitting

The advancement of a naturally rich and effective bifunctional substance for hydrogen and oxygen evolution reaction is crucial to enhance hydrogen fuel production efficiency via the electrolysis process. Herein, facile and scalable hydrothermal synthesis of bifunctional electrocatalyst of polyoxometalate anchored zinc cobalt sulfide nanowire on Ni-foam (NF) for overall water splitting is reported for the first time. The electrochemical analysis of POM@ZnCoS/NF displays significantly low HER and OER overpotentials of 170/337 and 200/300 mV to attain a current density of 10/40 and 20/50 mA cm⁻², respectively, demonstrating the notable performance of POM@ZnCoS/NF toward H₂ and O₂ evolution reaction in alkaline medium. Additionally, the electrolyzer consisting of the POM@ZnCoS/NF anode and cathode shows an appealing potential of 1.56 V to deliver 10 mA cm⁻² current density for overall water splitting. The high electrocatalytic activity of the POM@ZnCoS/NF is attributed to modulation of the electronic and chemical properties, increment of the electroactive sites and electrochemically active surface area of the zinc cobalt sulfide nanowires due to the anchorage of polyoxometalate nanoparticles. These results demonstrate the advantage of the polyoxometalate incorporation strategy for the design of cost-effective and highly competent bifunctional catalysts for complete water splitting.     

Heterometallic Seed-Mediated Zinc Deposition on Inkjet Printed Silver Nanoparticles Toward Foldable and Heat-Resistant Zinc Batteries

To achieve high performed zinc metal batteries, it is imperative to address the issues of dendrite growth and the side-reactions occurring at the Zn anode, particularly when the batteries are operated at high current densities and high temperature. Herein, a flexible and dendrite-free Zn metal anode (AgNPs@CC/Zn), which is prepared by inkjet printing silver nanoparticles on a 3D carbon matrix, is reported. Experimental observations and DFT calculation reveal that the Ag nanoparticles can work as heterometallic seeds for zinc deposition, and thus simultaneously improve the zincophilicity and thermal conductivity of the carbon matrix. This not only lowers the Zn nucleation overpotential and guides the uniform Zn nucleation but also promotes the reversible zinc stripping/plating via Ag Zn alloying/de-alloying reactions. As a result, the AgNPs@CC/Zn anode presents low voltage hysteresis of 80 mV and superior cycling over 480 h at a high current density of 10 mA cm⁻². The AgNPs@CC/Zn anode can enable full cells with exceptional cyclic stability and enhanced high-temperature endurance. Furthermore, the foldable pouch cell using the AgNPs@CC/Zn anode exhibits high capacity retention regardless of different deformation status. This work demonstrates the promising potential of inkjet printing technology in developing 3D dendrite-free zinc anode for foldable and heat-resistant zinc batteries.     

Amino Acid-Induced Interface Charge Engineering Enables Highly Reversible Zn Anode

Despite the impressive merits of low-cost and high-safety electrochemical energy storage for aqueous zinc ion batteries, researchers have long struggled against the unresolved issues of dendrite growth and the side reactions of zinc metal anodes. Herein, a new strategy of zinc-electrolyte interface charge engineering induced by amino acid additives is demonstrated for highly reversible zinc plating/stripping. Through electrostatic preferential absorption of positively charged arginine molecules on the surface of the zinc metal anode, a self-adaptive zinc-electrolyte interface is established for the inhibition of water adsorption/hydrogen evolution and the guidance of uniform zinc deposition. Consequently, an ultra-long stable cycling up to 2200 h at a high current density of 5 mA cm⁻² is achieved under an areal capacity of 4 mAh cm⁻². Even cycled at an ultra-high current density of 10 mA cm⁻², 900 h-long stable cycling is still demonstrated, demonstrating the reliable self-adaptive feature of the zinc-electrolyte interface. This work provides a new perspective of interface charge engineering in realizing highly reversible bulk zinc anode that can prompt its practical application in aqueous rechargeable zinc batteries.     

A Complexing Agent to Enable a Wide-Temperature Range Bromine-Based Flow Battery for Stationary Energy Storage

Bromine-based flow batteries (Br-FBs) are considered one of the most promising energy storage systems due to their features of high energy density and low cost. However, they generally suffer from uncontrolled diffusion of corrosive bromine particularly at high temperatures. That is because the interaction between polybromide anions and the commonly used complexing agent (N–methyl–N–ethyl–pyrrolidinium bromide [MEP]) decreases with increasing temperatures, which causes serious self-discharge and capacity fade. Herein, a novel bromine complexing agent, 1–ethyl–2–methyl–pyridinium bromide (BCA), is introduced in Br-FBs to solve the above problems. It is proven that BCA can combine with polybromide anions very well even at a high temperature of 60 °C. Moreover, the BCA contributes to decreasing the electrochemical polarization of Br⁻/Br₂ couple, which in turn improves their power density. As a result, a zinc–bromine flow battery with BCA as the complexing agent can achieve a high energy efficiency of 84% at 40 mA cm⁻², even at high temperature of 60 °C and it can stably run for more than 400 cycles without obvious performance decay. This paper provides an effective complexing agent to enable a wide temperature range Br-FB.     

3D Printed Nanocarbon Frameworks for Li-Ion Battery Cathodes

The use of conductive carbon materials in 3D-printing is attracting growing academic and industrial attention in electrochemical energy storage due to the high customization and on-demand capabilities of the additive manufacturing. However, typical polymers used in conductive filaments for 3D printing show high resistivity and low compatibility with electrochemical energy applications. Removal of insulating thermoplastics in as-printed materials is a common post-printing strategy, however, excessive loss of thermoplastics can weaken the structural integrity. This work reports a two-step surface engineering methodology for fabrication of 3D-printed carbon materials for electrochemical applications, incorporating conductive poly(ortho-phenylenediamine) (PoPD) via electrodeposition. A conductive PoPD effectively enhances the electrochemical activities of 3D-printed frameworks. When PoPD-refilled frameworks casted with LiMn₂O₄ (LMO) composite materials used as battery cathode, it delivers a capacity of 69.1 mAh g⁻¹ at a current density of 0.036 mA cm⁻² ( ≈ 1.2 C discharge rate) and good cyclability with a retained capacity of 84.4% after 200 cycles at 0.36 mA cm⁻². This work provides a pathway for developing electroactive 3D-printed electrodes particularly with cost-efficient low-dimensional carbon materials for aqueous rechargeable Li-ion batteries.     

Rational Design of Sulfonamide-Based Additive Enables Stable Solid Electrolyte Interphase for Reversible Zn Metal Anode

The solid electrolyte interphase (SEI)-forming additives strategy is of great significance for improving the cycle stability of zinc (Zn) anodes. Although various additives have been reported, the relationship between their molecular structures and SEI chemistries is poorly understood. Herein, a molecular design principle for sulfonamide-containing additives that endow Zn anodes with a robust SEI layer is proposed. The incorporation of the benzene ring and amino group (−NH₂) leads to high adsorption energy, low lowest unoccupied molecular orbital lowest unoccupied molecular orbital (LUMO), and a small highest occupied molecular orbital-LUMO (HOMO-LUMO) gap, facilitating the reduction process of sulfanilamide (SA) additives. Coupled with SA/ZnSO₄ electrolytes, Zn|Zn symmetric cells deliver an ultralong cycle life of 4800 h (200 days) at 2 mA cm⁻² and 2 mAh cm⁻². Additionally, a high cumulative plated capacity (CPC) of 6000 mAh cm⁻² and 2700 mAh cm⁻² is also achieved at a capacity per cycle of 10 mAh cm⁻² and 30 mAh cm⁻², respectively. More importantly, the versatility of SA additives is also demonstrated in Zn-V₂O₅, Zn-I₂, and Zn-MnO₂ full cells at a low N/P ratio (the theoretical capacity ratio between the negative and positive electrode) of 5.3, 8.3, and 4.5, respectively. This molecular structure strategy provides a promising path to develop effective SEI-forming additives.     

Active Site Implantation for Ni(OH)2 Nanowire Network Achieves Superior Hybrid Seawater Electrolysis at 1 A cm−2 with Record-Low Cell Voltage

Direct seawater electrolysis provides a grand blueprint for green hydrogen (H₂) technology, while the high energy consumption has severely hindered its industrialization. Herein, a promising active site implantation strategy is reported for Ni(OH)₂ nanowire network electrode on nickel foam substrate by Ru doping (denoted as Ru Ni(OH)₂ NW²/NF), which can act as a dual-function catalyst for hydrazine oxidation and hydrogen evolution, achieving an ultralow working potential of 114.6 mV to reach 1000 mA cm⁻² and a small overpotential of 30 mV at 10 mA cm⁻², respectively. Importantly, using the two-electrode hydrazine oxidation assisted seawater electrolysis, it can drive a large current density of 500 mA cm⁻² at 0.736 V with over 200 h stability. To demonstrate the practicability, a home-made flow electrolyzer is constructed, which can realize the industry-level rate of 1 A cm⁻² with a record-low voltage of 1.051 V. Theoretical calculations reveal that the Ru doping activates Ni(OH)₂ by upgrading d-band centers, which raises anti-bonding energy states and thus strengthens the interaction between adsorbates and catalysts. This study not only provides a novel rationale for catalyst design, but also proposes a feasible strategy for direct alkaline seawater splitting toward sustainable, yet energy-saving H₂ production.     

Coupling Methanol Oxidation with Hydrogen Evolution on Bifunctional Co-Doped Rh Electrocatalyst for Efficient Hydrogen Generation

Efficient hydrogen production from electrochemical overall water splitting requires high-performance electrocatalysts for hydrogen evolution reaction (HER) and a fast oxidation reaction to replace sluggish oxygen evolution reaction. Herein, Co-doped Rh nanoparticles are thus grown on carbon black using Co nanosheets as the bridge. These nanoparticles with a size of ≈1.94 nm exhibit the overpotential of as low as 2 mV at 10 mA cm⁻² for the HER, and a mass activity of as high as 889 mA mg⁻¹ for the methanol oxidation reaction (MOR) in alkaline media. As confirmed by density functional theory simulations, such excellent activity originates from Co-doping, which reduces reaction energy barriers for both the rate-determining step of a Volmer process during the HER and the conversion of *CO to COOH* during the MOR (namely the enhanced adsorption of H₂O and COOH*). Coupling boosted HER on the cathode with accelerated MOR on the anode, efficient H₂ generation is achieved. This two-electrode cell only requires a cell voltage of 1.545 V at 10 mA cm⁻² with impressive long-life cycling stability. Such performance even outperforms that of commercial Pt/C || IrO₂ cell. This study offers a new strategy to achieve efficient HER from overall water splitting.     

Pyrolysis of Enzymolysis-Treated Wood: Hierarchically Assembled Porous Carbon Electrode for Advanced Energy Storage Devices

Designing energy storage devices from thick carbon electrodes with high areal/volumetric energy density via a simple and green way is very attractive but still challenging. Cellulose, as an excellent precursor for thick carbon electrodes with abundant sources and low cost, is usually activated by a chemical activator and pyrolysis route to achieve high electrochemical performance. However, there are still some problems to be addressed, such as the harsh activation conditions, easy collapse of porous structures, and the high cost. Herein, a 3D self-supporting thick carbon electrode derived from wood-based cellulose is proposed for high areal and volumetric energy density of supercapacitor from a mild, simple, and green enzymolysis treatment. Benefiting from the high specific surface area (1418 m² g⁻¹) and abundant active sites on the surface of wood-derived hierarchically porous structures and enzymolysis-induced micropores and mesopores, the assembled symmetry supercapacitor from the thick carbon electrode can realize the high areal/volumetric energy density of 0.21 mWh cm⁻²/0.99 mWh cm⁻³ with excellent stability of 86.58% after 15 000 long-term cycles at 20 mA cm⁻². Significantly, the simple and universal strategy to design material with high specific surface area, provides a new research idea for realizing multi-functional application.