Power Density Research Articles

Planar Chlorination Engineering: A Strategy of Completely Breaking the Geometric Symmetry of Fe-N4 Site for Boosting Oxygen Electroreduction.

Introducing asymmetric elements and breaking the geometric symmetry of traditional metal-N4 site for boosting oxygen reduction reaction (ORR) are meaningful and challenging. Herein, the planar chlorination engineering of Fe-N4 site is first proposed for remarkably improving the ORR activity. The Fe-N4/CNCl catalyst with broken symmetry exhibits a half-wave potential (E1/2) of 0.917V versus RHE, 49 and 72mV higher than those of traditional Fe-N4/CN and commercial 20 wt% Pt/C catalysts. The Fe-N4/CNCl catalyst also has excellent stability for 25000 cycles and good methanol tolerance ability. For Zn-air battery test, the Fe-N4/CNCl catalyst has the maximum power density of 228mW cm-2 and outstanding stability during 150h charge-discharge test, as the promising substitute of Pt-based catalysts in energy storage and conversion devices. The density functional theory calculation demonstrates that the adjacent C─Cl bond effectively breaks the symmetry of Fe-N4 site, downward shifts the d-band center of Fe, facilitates the reduction and release of OH*, and remarkably lowers the energy barrier of rate-determining step. This work reveals the enormous potential of planar chlorination engineering for boosting the ORR activity of traditional metal-N4 site by thoroughly breaking their geometric symmetry.

Spontaneously established reverse electric field to enhance the performance of triboelectric nanogenerators via improving Coulombic efficiency

Mechanical energy harvesting using triboelectric nanogenerators is a highly desirable and sustainable method for the reliable power supply of widely distributed electronics in the new era; however, its practical viability is seriously challenged by the limited performance because of the inevitable side-discharge and low Coulombic-efficiency issues arising from electrostatic breakdown. Here, we report an important progress on these fundamental problems that the spontaneously established reverse electric field between the electrode and triboelectric layer can restrict the side-discharge problem in triboelectric nanogenerators. The demonstration employed by direct-current triboelectric nanogenerators leads to a high Coulombic efficiency (increased from 28.2% to 94.8%) and substantial enhancement of output power. More importantly, we demonstrate this strategy is universal for other mode triboelectric nanogenerators, and a record-high average power density of 6.15 W m−2 Hz−1 is realized. Furthermore, Coulombic efficiency is verified as a new figure-of-merit to quantitatively evaluate the practical performance of triboelectric nanogenerators.

Engineering of Pt@Ni,N-doped graphene electrocatalyst based on recycled water bottles waste as an efficient cathode material for PEM fuel cells

Fuel cells (FCs) represent one of the most promising clean power sources. Their cost represents a considerable challenge to their widespread commercialization because of their sensitivity and the expensive cost of the employed platinum electrocatalysts. Accordingly, one feature of a fuel cell device that many interested parties are looking for is the engineering of catalysts with a low Pt content. Herewith, Pt supported on nickel loaded nitrogen-doped graphene (Pt@Ni,N-G) was synthesized through a simple pyrolysis process of mineral water bottles waste with urea and nickel metal at 800 °C followed by loading Pt in different proportions via a simple reduction method in aqueous solution at room temperature. The physicochemical and electrochemical properties of a promising Pt@Ni,N-G cathode electrocatalyst for polymer electrolyte membrane fuel cell (PEMFC) were characterized and evaluated using a number of specialized techniques. The results showed that the high Pt@Ni,N-G content enhanced the catalytic activity of the oxygen reduction reaction (ORR), with a specific activity of 3.13 mA cm−2 and a mass activity of 12.35 mA μg−1Pt at −0.1 V. A maximum power density of 87.8 mW cm−2 was achieved which is closest to that of commercial Pt/C. Designing Pt@Ni,N-G electrocatalysts by recycling waste bottles is not only expected to reduce the cost of fuel cells by ~30 % to raise the industry standard but also protect the environment and humanity from harmful pollutants.

High-performance piezoelectric energy harvesting in amorphous perovskite thin films deposited directly on a plastic substrate

Most reported thin-film piezoelectric energy harvesters have been based on cantilever-type crystalline ferroelectric oxide thin films deposited on rigid substrates, which utilize vibrational input sources. Herein, we introduce flexible amorphous thin-film energy harvesters based on perovskite CaCu3Ti4O12 (CCTO) thin films on a plastic substrate for highly competitive electromechanical energy harvesting. The room-temperature sputtering of CCTO thin films enable the use of plastic substrates to secure reliable flexibility, which has not been available thus far. Surprisingly, the resultant amorphous nature of the films results in an output voltage and power density of ~38.7 V and ~2.8 × 106 μW cm−3, respectively, which break the previously reported record for typical polycrystalline ferroelectric oxide thin-film cantilevers. The origin of this excellent electromechanical energy conversion is systematically explored as being related to the localized permanent dipoles of TiO6 octahedra and lowered dielectric constant in the amorphous state, depending on the stoichiometry and defect states. This is the leading example of a high-performance flexible piezoelectric energy harvester based on perovskite oxides not requiring a complex process for transferring films onto a plastic substrate.

Eggshell-Like Carbon Microspheres with Curvature Scheme: Distorted Energy Band and Atomic Charge Waves-Driven High Performance for Zinc-Air Battery.

A metal-free nanocarbon with an eggshell structure is synthesized from chitosan (CS) and natural spherical graphite (NSG) as a cathode electrocatalyst for clean zinc-air batteries and fuel cells. It is developed using CS-derived carbons as an eggshell, covering NSG cores. The synthesis involves the in situ growth of CS on NSG, followed by ammonia-assisted pyrolysis for carbonization. The resulting catalyst displays a curved structure and completely coated NSG, showing superior oxygen reduction reaction (ORR) performance. In 1 M NaOH, the ORR half-wave potential reached 0.93 V, surpassing the commercial Pt/C catalyst by 50 mV. Furthermore, a zinc-air battery featuring the catalyst achieves a peak power density of 167 mW cm-2 with excellent stability, outperforming the Pt/C. The improved performance of the eggshell carbons can be attributed to the distorted energy band of the active sites in the form of N-C moieties. More importantly, the curved thin eggshells induce built-in electric fields that can promote electron redistribution to generate atomic charge waves around the N-C moieties on the carbon shells. As a result, the high positively charged and stable C+ sites adjacent to N atoms optimize the adsorption strength of oxygen molecules, thereby facilitating performance.

A sustainable solution: Conversion of distillers' grains waste into high-performance supercapacitor electrode materials for energy storage applications

The development of cost-effective biomass-derived carbon with good electrochemical properties is crucial for advancing energy storage devices sustainably. One feasible approach to producing supercapacitor electrode materials is the conversion of heteroatom-rich biomass waste into heteroatom self-doped hierarchical porous carbons with favorable electrochemical properties. In this study, distillers' grains with abundant crude fiber and protein were utilized as precursors to prepare N, S self-doped hierarchical porous carbon, which presents a high specific surface area of 3642.87 m2 g−1. The N, S doping could improve the interfacial wettability of electrode materials and enhance the pseudocapacitive effect of the materials. In three-electrode system, the carbon delivered a high capacitance of 347 F g−1 at 1 A g−1. Symmetrical capacitors assembled with PVA/KOH gel electrolytes delivered an ultrahigh energy density of 11.29 Wh kg−1 at a power density of 250 W kg−1. This strategy provides a practical, low-cost, and renewable design approach of carbon electrode for high-performance supercapacitors.

Oxygen Vacancy-Rich NiCo2O4 on Carbon Framework with Controlled Pore Architectures as Efficient Bifunctional Electrocatalysts for Zn-Air Batteries

Transition metal oxides are considered alternative electrocatalysts for ZAB owing to their multiple oxidation states. However, they have limitations such as low electrical conductivity and the deficiency of reactive sites. In this study, to overcome these shortcomings and improve electrocatalytic activity, oxygen vacancies and porous architectures were introduced through a partial reduction process and a porous carbon framework. Open porous carbon microspheres with uniformly loaded NiCo2O4 nanosheets and oxygen vacancies (V-NCO/OPC) displayed enhanced electrocatalytic performance with a low Tafel slope (68 mV dec-1) in the oxygen reduction reaction (ORR) and a low overpotential (402 mV) at 10 mA cm–2 in the oxygen evolution reaction (OER). The combined effect of the oxygen vacancies and porous architecture can offer sufficient active sites, modify the electronic structure of the metal oxide surface, and facilitate mass transport, enhancing the electrocatalytic properties of V-NCO/OPC. Furthermore, when applied for ZAB, V-NCO/OPC demonstrated better electrochemical performance including discharge power density (154.9 mW cm-2) at the current density of 175.9 mA cm-2, low voltage gap (0.85 V) at the initial cycle, and long-term (250 h) cycle stability at the current density of 10 mA cm−2 than those of noble-metal electrocatalysts.

Optimizing Transport Carrier Free All-Polymer Solar Cells for Indoor Applications: TCAD Simulation under White LED Illumination.

This work inspects the utilization of all-polymer solar cells (APSCs) in indoor applications under LED illumination, with a focus on boosting efficiency through simulation-based design. The study employs a SCAPS TCAD device simulator to investigate the performance of APSCs under white LED illumination at 1000 lux, with a power density of 0.305 mW/cm2. Initially, the simulator is validated against experimental results obtained from a fabricated cell utilizing CD1:PBN-21 as an absorber blend and PEDOT:PSS as a hole transportation layer (HTL), where the initial measured efficiency is 16.75%. The simulation study includes an examination of both inverted and conventional cell structures. In the conventional structure, where no electron transportation layer (ETL) is present, various materials are evaluated for their suitability as the HTL. NiO emerges as the most promising HTL material, demonstrating the potential to achieve an efficiency exceeding 27%. Conversely, in the inverted configuration without an HTL, the study explores different ETL materials to engineer the band alignment at the interface. Among the materials investigated, ZnS emerges as the optimal choice, recording an efficiency of approximately 33%. In order to reveal the efficiency limitations of these devices, the interface and bulk defects are concurrently investigated. The findings of this study underscore the significance of careful material selection and structural design in optimizing the performance of APSCs for indoor applications.

Co nanoparticle-loaded porous carbon for high-performance supercapacitors

Porous carbon materials doped with transition metals have emerged as promising electrode materials in the field of energy storage due to their higher theoretical capacitance and cost-effectiveness. In this study, metallic cobalt nanoparticles (Co NPs) were successfully loaded into porous carbon via one-step carbonization method for electrochemical research applications as electrode materials (Co/CM). A comparative investigation was conducted by varying the content of polystyrene microspheres (PS) to optimize the porous morphology. Scanning electron microscopy (SEM) analysis revealed that the Co/CM-3 composite displayed a plate-like porous structure, while transmission electron microscopy (TEM) confirmed the uniform loading of Co NPs within the porous carbon skeleton. The composite with the optimal PS content (Co/CM-3) exhibited a specific capacitance of up to 810 F g−1 (at 1 A g−1) in the three-electrode system. Furthermore, asymmetric supercapacitors assembled with the prepared electrode as the positive electrode and activated carbon as the negative electrode demonstrated an impressive energy density of up to 40 Wh kg−1 (at a power density of 746 W kg−1). Remarkably, the capacitance retention rate remained at 88.24 % even after 5000 consecutive charge and discharge cycles, highlighting the promising potential of this electrode material for practical applications in energy storage.

Basic and acidic electrolyte mediums impact on MnO2-Mn2O3/Poly-2-methylaniline hexagonal nanocomposite pseudo-supercapacitor

A highly efficient MnO2-Mn2O3/Poly-2-methylaniline (MnO2-Mn2O3/P2MA) hexagonal nanocomposite is synthesized using a one-pot technique involving oxidation polymerization. The hexagonal morphology and crystalline nature of this nanocomposite, as evidenced by the XRD pattern, affirm its exceptional characteristics. The electrical properties are assessed through charge/discharge behavior and cyclic voltammetry curves, elucidating the storage capabilities of this pseudo supercapacitor using different electrolytes NaOH and HCl. The fabricated supercapacitor exhibits impressive efficiency values of 22 F g−1 in a basic medium and a notably higher 72 F g−1 in an acidic medium at a current density of 0.2 A/g. Similarly, the power density values are calculated at 480 and 478 W.kg−1 for the basic and acidic electrolyte, correspondingly. In the basic medium, the series resistance (RS) and charge transfer resistance (RCT) are 5.2 and 0.7 Ω, respectively. In the acidic medium, these values are notably lower, with RS at 2.82 Ω and RCT at 0.2 Ω. Remarkably, even after 500 cycles, the supercapacitor stability remains high at 95% in both media, underscoring the enduring stability attributed to the oxides and polymer materials within the supercapacitor. The combination of cost-effectiveness, ease of fabrication, and potential for mass production positions this supercapacitor as a promising candidate for industrial applications of polymer-based supercapacitors.

Coconut Husk Waste‐Derived Nitrogen‐Doped Mesoporous Carbon Nanomaterial as an Efficient and Sustainable Supercapacitor

Sustainability and waste management are equally important in the era of growing energy demands. This study focuses on integrating strategies that balance energy efficiency, reduce waste generation, and promote sustainable practices. The coconut husk is processed and converted into mesoporous carbon nanomaterial through hydrothermal‐assisted thermal annealing. Nitrogen is doped through melamine to increase reactive sites and hence the catalytic activity. The sphere‐like morphology was confirmed by field emission scanning electron microscope and high‐resolution transmission electron microscope images indicate a carbon dot‐like structure. The high Brunauer‐Emmett‐Teller surface area achieved for this nanostructure is 1383.40 m2 g−1, with pore width and volume at 2.2660 nm and 0.2995 cm3 g−1, respectively. The as‐synthesized nanostructure is explored for its electrochemical performance as electrodes for the supercapacitor application, where materials achieve a wide potential window (−1.4 to 1.4 V) in the minimum time of 50 s at the current density of 0.6 A g−1. Moreover, the highest specific capacitance obtained from the nanomaterial is 115.39 F g−1 in the potential window and current density of 2 V and 0.6 A g−1, respectively. The energy density, power density, and coulombic efficiency at the set parameter are 62.31 Wh Kg−1, 1166.4 W Kg−1, and 79.61%, respectively. Finally, the practical device is assembled with the nanomaterial, where a red LED bulb glows after 1 min of charging.

A Remarkable Pt Doped CNT Catalyst as a Double Functional Material: Its Application for Hydrogen Production and Supercapacitor

In this study, by producing bifunctional material, hydrolysis, and supercapacitor applications were investigated. The carbon nanotube-supported Pt catalyst was prepared using the sodium borohydride (NaBH<sub>4</sub>) reduction. Surface characterization of the synthesized Pt/CNT catalyst was performed using scanning electron microscopy-energy dıstrıbutıon X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Hydrolysis experiments were performed after deciding on the appropriate atomic ratio from the Pt/CNT catalysts synthesized in different nuclear ratios. The parameters affecting the hydrogen production from NaBH<sub>4</sub> were examined. As a result of the kinetic calculations, the initial rates of reaction for 30°C and 60°C were calculated as 21949,69 mlH<sub>2</sub>g<sub>cat</sub>min<sup>-1</sup> and 70018,18 mlH<sub>2</sub>g<sub>cat</sub>min<sup>-1</sup>. Galvastonic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used as characterization techniques for the use of Pt/CNT catalysts as electrodes in supercapacitor applications. The specific capacitance value of 7% Pt/CNT catalyst at 1 A/g current density was calculated as 57,78 F/g. Energy and power density were calculated as 8,025 Wh/kg and 963 W/kg, respectively. Therefore, this catalyst is called a “cap-cat” with capacitor properties. The catalyst used in this study is promising for this recently studied topic.

Strain engineering of Bi2S3 microspheres via organic intercalation enabled high performance sodium storage

Conversion or alloying-type layered metal chalcogenides, which hold great promise as anodes for sodium storage, encounter a significant challenge of volume expansion due to the accumulation of inner strain during the charge–discharge process. This issue leads to severe stress concentration and necessitates urgent attention in terms of dispersing the distribution of inner strain through advanced strain engineering techniques. In this study, we have successfully fabricated Bi2S3-TTAB microspheres composed of Bi2S3 nanorods intercalated with tetradecyltrimethylammonium bromide (TTAB). By periodically inserting the soft TTAB into the interlayer of Bi2S3, we effectively isolate and confine the Bi2S3 layers while simultaneously expanding the interlamellar spacing. This innovative approach disperses and alleviates the inner strain of Bi2S3 at an atomic level, thereby ensuring electrode stability. As a competitive conversion-alloying-type anode for sodium-ion batteries, the Bi2S3-TTAB microspheres demonstrate remarkable performance in terms of high rate capacities and cycle stability (208.4 mAh g−1 at 15 A g−1; 4910 cycles at 10 A g−1 with 87.8 % capacity retention). This exceptional Na-ion storage capability enables the utilization of Bi2S3-TTAB combined with active carbon as an advanced sodium ion capacitor that demonstrates impressive energy and power densities (144.0 Wh kg−1 and 5.0 kW kg−1).

Supercapacitor performance enhancement with the BaS3:Cu2S:Mn2S trichalcogenide semiconductor synthesized via dithiocarbamate precursors

AbstractDue to its potential uses, including e‐vehicles, electrochemical energy storage has attracted a lot of interest from the scientific community and energy stakeholders. With the usage of the novel semiconductor chalcogenide BaS3:Cu2S:Mn2S, which is synthesized by chelating with diethyldithiocarbamate ligand, the current work seeks to enhance the performance of charge‐storage devices. An energy band gap of 2.57 eV was found for this semiconductor, which showed remarkable photoactivity. The chalcogenide that was produced had favorable crystallinity, with an average crystallite size of 26.92 nm and mixed crystalline phases. Additionally, metallic sulfide linkages were identified using infrared spectroscopy, and they were reported to range from 400 to 845 cm−1. Thermal breakdown in two steps was verified using thermogravimetric analysis. Particles with different forms and a rod‐like fusion suggested a higher volume–surface area ratio and many locations. The electrochemical performance of the BaS3:Cu2S:Mn2S was evaluated using a traditional three‐electrode setup with a background electrolyte of 1‐M KOH. BaS3:Cu2S:Mn2S is a great electrode material for energy storage applications, with a specific power density of 10 618 W kg−1 and a specific capacitance of up to 694 F g−1. The same series resistance (Rs) = 0.46 Ω further supported this remarkable electrochemical performance.

Seeded Growth of Size-Tunable Au@Ag Core-Shell Nano-Octahedra and Their Yolk-Shell Derivatives for Near Infrared Photothermal Conversion.

Gold-based nanostructures with well-defined morphologies and hollow interiors have significant potential as a versatile platform for various plasmonic applications including biomedical diagnostics and sensing. In this study, we report the synthesis of Au@Ag core-shell nanocrystals with perfect octahedral shapes and tunable edge lengths via seeded growth. These nanocrystals were then oxidatively carved into yolk-shell nanocages with a retained octahedral morphology. The increase in octahedral edge length and volume of the interior hollow cavity synergistically leads to a red-shift of the LSPR peak. As a result, the optimized Au@AuAg yolk-shell octahedral nanocages showed a remarkable temperature increase of 23 °C upon 15 min irradiation of an 808 nm laser at a power density of 1 W cm-2. This study provides a feasible strategy for creating octahedral AuAg nanostructures with tunable sizes and hollow interiors and validates their promising use in NIR photothermal conversion.

Unveiling the Impact of Tailoring Ionic Conductor Characteristics on the Performance of Wearable Triboelectric Nanogenerators.

This work reveals the correlation between the performance of triboelectric nanogenerators (TENGs) and the characteristics of deformable solid-state ionic conductors (referred to as ionogels). For this purpose, we modify ionogel characteristics by incorporating additional plasticizers (propylene carbonate) and solid salts (lithium bis(trifluoromethylsulfonyl)imide) into the ionogels. We conclude that the high capacitance of the ionogel is crucial for achieving a high-performance TENG platform. The optimized ionogel-based TENG (i-TENG) exhibits a power density of ∼372.4 mW·m-2 (based on 95 V and 36 mA·m-2 outputs) with outstanding long-term stability over 2 weeks. Additionally, successful demonstrations of wearable nanogenerators are performed by leveraging the high stretchability (up to ∼1000%) and optical transparency (∼90%) of the ionogels. Overall, the results provide insight into the design of deformable ionic conductors for high-performance, reliable, and wearable TENGs.

2D-on-2D Al-Doped NiCo LDH Nanosheet Arrays for Fabricating High-Energy-Density, Wide Voltage Window, and Ultralong-Lifespan Supercapacitors.

Battery-type electrode materials with high capacity, wide potential windows, and good cyclic stability are crucial to breaking through energy storage limitations and achieving high energy density. Herein, a novel 2D-on-2D Al-doped NiCo layered double hydroxide (NiCoAlx LDH) nanosheet arrays with high-mass-loading are grown on a carbon cloth (CC) substrate via a two-step hydro/solvothermal deposition strategy, and the effect of Al doping is employed to modify the deposition behavior, hierarchical morphology, phase stability, and multi-metallic synergistic effect. The optimized NiCoAl0.1 LDH electrode exhibits capacities of 5.43, 6.52, and 7.25 C cm-2 (9.87, 10.88, and 11.15 F cm-2) under 0-0.55, 0-0.60, and 0-0.65V potential windows, respectively, illustrating clearly the importance of the wide potential window. The differentiated deposition strategy reduces the leaching level of Al3+ cations in alkaline solutions, ensuring excellent cyclic performance (108% capacity retention after 40000 cycles). The as-assembled NiCoAl0.1 LDH//activated carbon cloth (ACC) hybrid supercapacitor delivers 3.11 C cm-2 at 0-2.0V, a large energy density of 0.84 mWh cm-2 at a power density of 10.00mW cm-2, and excellent cyclic stability with ≈135% capacity retention after 150000 cycles.

Degradation of potato peels using amylase- and pectinase-producing fungal strain in an electrochemical cell and by-product analysis

ABSTRACT Degradation of the waste using amylase- and pectinase-producing fungal strains in Microbial fuel cells (MFC) can be a sustainable and economic strategy for solid waste management. An isolate of the fungal strain Aspergillus niger, which showed amylase and pectinase activities was implemented for potato peel waste degradation. MFC was constructed and the highest OCV was observed using KMnO4 in catholyte (1586 ± 63 mV/m3) with anode graphite electrode-coated MWCNT. MFC in fed-batch mode was also performed by adding 10% of the sample every 24 h, and an improved result was obtained. The power density observed with 100-ohm and 1000-ohm external resistors was 119 ± 7 W/m3 and 42 ± 9 W/m3, respectively. From MFC operation at an optimised condition removal rate of COD, ammoniacal-nitrogen, reducing sugar and TSS were 37.69%, 67.72%, 72.64%, and 65.95% respectively. Sugar and byproduct analysis in digested product was done by HPLC, various value-added products were generated from waste sample.

Completely Methylene-Free Side Chain Enables Significant Microphase Separation at Medium IECs for Fuel-Cell Anion Exchange Membranes.

The introduction of hydrophobic side chain structures in anion exchange membranes (AEMs) to facilitate ion transport has been widely studied; however, low or moderate hydrophobic hydrocarbon and semifluorinated side chains are insufficient to induce a high degree of microphase separation. Herein, we design and prepare poly(aryl piperidinium) AEMs with completely methylene-free perfluorinated side chains, which can maximize the thermodynamic incompatibility between main- and side chains, thus enhancing microphase separation at medium ion exchange capacities (IECs). According to the molecular dynamics study, the methylene-free perfluorinated side chain leads to better hydration of cations. The hydroxide conductivity of the methylene-free perfluorinated side chain-grafted PAP-pF-1 membrane reaches 124.9 mS cm-1 at 80 °C, and the PAP-sF-1 with semifluorinated side chains and PAP-CH-1 with hydrocarbon side chains show lower conductivity (116.8 and 104.0 mS cm-1). The H2/O2 fuel cell using the PAP-pF-1 membrane demonstrates a remarkable peak power density (1651 mW cm-2 at 80 °C) and durability (greater than 300 h). This work provides a novel insight into enhancing microphase separation in AEMs; it opens up new possibilities for developing high-performance AEMs.

A Vacuum Vapor Deposition Strategy to Fe Single-Atom Catalysts with Densely Active Sites for High-Performance Zn-Air Battery.

Iron single-atom catalysts (SACs) have garnered increasing attention as highly efficient catalysts for the oxygen reduction reaction (ORR), yet their performance in practical devices remains suboptimal due to the low density of accessible active sites. Anchoring iron single atoms on 2D support is a promising way to increase the accessible active sites but remains difficult attributing to the high aggregation tendency of iron atoms on the 2D support. Herein, a vacuum vapor deposition strategy is presented to fabricate an iron SAC supported on ultrathin N-doped carbon nanosheets with densely active sites (FeSAs-UNCNS). Experimental analyses confirm that the FeSAs-UNCNS achieves densely accessible active sites (1.11×1020sitesg-1) in the configuration of Fe─N4O. Consequently, the half-wave potential of FeSAs-UNCNS in 0.1m KOH reaches a remarkable value of 0.951V versus RHE. Moreover, when employed as the cathode of various kinds of Zn-air batteries, FeSAs-UNCNS exhibits boosting performances by achieving a maximum power density of 306mWcm-2 and long cycle life (>180h) at room temperature, surpassing both Pt/C and reported SACs. Further investigations reveal that FeSAs-UNCNS facilitates the mass and charge transfer during catalysis and the atomic configuration favors the desorption of *OH kinetically.