Single-crystalline metal-oxide dielectrics for top-gate 2D transistors.

Two-dimensional (2D) structures composed of atomically thin materials with high carrier mobility have been studied as candidates for future transistors1-4. However, owing to the unavailability of suitable high-quality dielectrics, 2D field-effect transistors (FETs) cannot attain the full theoretical potential and advantages despite their superior physical and electrical properties3,5,6. Here we demonstrate the fabrication of atomically thin single-crystalline Al2O3 (c-Al2O3) as a high-quality top-gate dielectric in 2D FETs. By using intercalative oxidation techniques, a stable, stoichiometric and atomically thin c-Al2O3 layer with a thickness of 1.25 nm is formed on the single-crystalline Al surface at room temperature. Owing to the favourable crystalline structure and well-defined interfaces, the gate leakage current, interface state density and dielectric strength of c-Al2O3 meet the International Roadmap for Devices and Systems requirements3,5,7. Through a one-step transfer process consisting of the source, drain, dielectric materials and gate, we achieve top-gate MoS2 FETs characterized by a steep subthreshold swing of 61 mV dec-1, high on/off current ratio of 108 and very small hysteresis of 10 mV. This technique and material demonstrate the possibility of producing high-quality single-crystalline oxides suitable for integration into fully scalable advanced 2D FETs, including negative capacitance transistors and spin transistors.

A Triple Crosslinked Binder with Hierarchical Stress Dissipation and High Ionic Conductivity for Advanced Silicon Anodes in Lithium-ion Batteries.

Silicon (Si) is a promising anode material for high-energy-density lithium-ion batteries, but the significant volume change of Si particles during alloying/dealloying with lithium (Li) undermines the mechanical integrity of Si anode, causing electrode fracture, delamination and rapid capacity decay. Herein, a robust triple crosslinked network (TCN) binder with high ionic conductivity and hierarchical stress dissipation is reported for Si anodes, which is prepared by in situ chemical crosslinking polyacrylic acid (PAA) and melamine (MA). The triple interactions of hydrogen bonds, electrostatic interactions, and covalent amide bonds enhance the adhesion of binder to Si and synergistically promote stress dissipation within Si anodes, thus strengthening the dynamic structural stability of Si anodes during cycling. Moreover, the rapid coupling/decoupling of Li+ with the TCN binder enables an impressive Li+ transference number of 0.63 and high ionic conductivity of 1.2 × 10-4 S cm-1. Consequently, the Si-TCN anode delivers specific capacity of 2268 mAh g-1 with a high mass loading of 2 mg cm-2, high-rate performance of 1673 mAh g-1 at 5 A g-1, and stable cycling for 250 cycles at 1 A g-1, thus showing great prospects for high-energy-density Si-based batteries.

Fabrication of Single-Crystal Violet Phosphorus Flakes For Ultrasensitive Photodetection.

Violet phosphorus (VP) has attracted a lot of attention for its unique physicochemical properties and emerging potential in photoelectronic applications. Although VP has a van der Waals (vdW) structure similar to that of other 2D semiconductors, direct synthesis of VP on a substrate is still challenging. Moreover, optoelectronic devices composed of transfer-free VP flakes have not been demonstrated. Herein, a bismuth-assisted vapor phase transport technique is designed to grow uniform single-crystal VP flakes on the SiO2/Si substrate directly. The size of the crystalline VP flakes is an order of magnitude larger than that of previous liquid-exfoliated samples. The photodetector fabricated with the VP flakes shows a high responsivity of 12.5 A W-1 and response/recovery time of 3.82/3.03 ms upon exposure to 532 nm light. Furthermore, the photodetector shows a small dark current (<1 pA) that is beneficial to high-sensitivity photodetection. As a result, the detectivity is 1.38 × 1013 Jones that is comparable with that of the vdW p-n heterojunction detector. The results reveal the great potential of VP in optoelectronic devices as well as the CVT technique for the growth of single-crystal semiconductor thin films.

Using machine learning to enlarge the measurement range and promote the compactness of the optical fiber torsion sensor based on the Sagnac interferometer.

The support vector regression (SVR) algorithm is presented to demodulate the torsion angle of an optical fiber torsion sensor based on the Sagnac interferometer with the panda fiber. Experimental results demonstrate that with the aid of SVR algorithm, the information in the transmission spectrum of the sensor can be used fully to realize the regression prediction of the directional torsion angle. The full torsion angle ranges from -360° to 360° can be predicted with a mean absolute error (MAE) of 2.24° and determination coefficient (R2) of 0.9996. The impact of the angle sampling interval and wavelength resolution of the spectrometer on the prediction accuracy of the directional torsion angle and the suitability of the SVR algorithm for compact optical fiber sensor and other optical fiber torsion sensors based on the Sagnac interferometer are discussed. Moreover, the multi-objective SVR algorithm is used to eliminate the interference of strain during torsion angle measurement. The SVR algorithm can efficiently enlarge the measurement range of the torsion angle and break through the challenge of demodulating sensing signal for compact fiber torsion sensor. Compared to the prediction accuracy of common machine learning algorithms of artificial neural network (ANN) algorithm, random forest (RF) algorithm, and K-nearest neighbor (KNN) algorithm, the SVR algorithm has the advantages of higher measurement accuracy and shorter testing time.

Ultra-high sensitivity weak magnetic field detecting magnetic fluid surface plasmon resonance sensor based on a single-hole fiber.

An ultra-high sensitivity weak magnetic field detecting magnetic fluid surface plasmon resonance (SPR) sensor based on a single-hole fiber (SHF) is proposed for detecting weak magnetic fields. The sensor is constructed with a single-hole fiber in which an exclusive air hole in the cladding is embedded with a metal wire and filled with a magnetic fluid (MF) to enhance the magnetic field sensitivity. The effects of the structural parameters, embedded metals, and refractive index difference between the core and cladding on the magnetic field sensitivity and peak loss are investigated and optimized. The sensitivity, resolution, figure of merit (FOM), and other characteristics of the sensor are analyzed systematically. The numerical results reveal a maximum magnetic field sensitivity of 451,000 pm/mT and FOM of 15.03 mT-1. The ultra-high magnetic field sensitivity renders the sensor capable of detecting weak magnetic fields at the pT level for the first time, in addition to a detection range from 3.5 mT to 17 mT. The SHF-SPR magnetic field sensor featuring high accuracy, simple structure, and ease of filling has immense potential in applications such as mineral resource exploration as well as geological and environmental assessment.

High-sensitivity strain sensor based on an asymmetric tapered air microbubble Fabry-Pérot interferometer with an ultrathin wall.

A Fabry-Pérot interferometer (FPI) with an asymmetric tapered structure and air microbubble with an ultrathin wall is designed for high-sensitivity strain measurement. The sensor contains an air microbubble formed by two single-mode fibers (SMF) prepared by fusion splicer arc discharge, and a taper is applied to one side of the air microbubble with a wall thickness of 3.6 µm. In this unique asymmetric structure, the microbubble is more easily deformed under stress, and the strain sensitivity of the sensor is up to 15.89 pm/µÉ› as evidenced by experiments.The temperature sensitivity and cross-sensitivity of the sensor are 1.09 pm/°C and 0.069 µÉ›/°C in the temperature range of 25-200°C, respectively, thus reducing the measurement error arising from temperature variations. The sensor has notable virtues such as high strain sensitivity, low-temperature sensitivity, low-temperature cross-sensitivity, simple and safe process preparation, and low cost. Experiments confirm that the sensor has good stability and repeatability, and it has high commercial potential, especially strain measurements in complex environments.

First-principles study of multifunctional Mn2B3 materials with high hardness and ferromagnetism.

Transition metal boride TM2B3 is widely studied in the field of physics and materials science. However, Mn2B3 has not been found in Mn-B systems so far. Mn2B3 undergoes phase transitions from Cmcm (0-28 GPa) to C2/m (28-80 GPa) and finally to C2/c (80-200 GPa) under pressure. Among these stable phases, Cmcm- and C2/m-Mn2B3s comprise six-membered boron rings and C2/c-Mn2B3 has wavy boron chains. They all have good mechanical properties and can become potential multifunctional materials. The strong B-B covalent bonding is mainly responsible for the structural stability and hardness. Comparison of the hardness of the five TM2B3s with different bonding strengths of TM-B and B-B bonds reveals a nonlinear change in the hardness. According to the Stoner model, these structures possess ferromagnetism, and the corresponding magnetic moments are almost the same as those of GGA and GGA + U (U = 3.9 eV, J = 1 eV).

High-sensitivity dual U-shaped PCF-SPR refractive index sensor for the detection of gas and liquid analytes.

A dual U-shaped photonic crystal fiber (PCF) biochemical sensor based on surface plasmon resonance (SPR) is designed for the simultaneous detection of gas and liquid analytes, and the properties are analyzed by the full vector finite element method (FEM). SPR is excited by placing gold nanowires on the inner surface of the U-shaped device. In this technique, the traditional metal deposition process can be replaced, subsequently reducing the difficulty and complexity of actual production and improving the phase matching between the basic mode and plasmonic modes. To improve the detection properties, the structural parameters of the sensor including the air hole diameter, spacing, gold nanowire diameter, and polishing depth are optimized, and to better evaluate and analyze the sensing properties, the wavelength and amplitude modulation inquiry method is adopted. The results show that the maximum wavelength sensitivity (WS), amplitude sensitivity (AS), minimum resolution (R), and optimal FOM are 35,000 nm/RIU, 438.08R I U -1, 2.86×10-6 R I U, and 165.16R I U -1, respectively. In addition, the sensor can detect analyte RIs between 1.00 and 1.36 for gas and liquid analytes simultaneously. Owing to the simple structure, low cost, and ambient-condition monitoring, the sensor has large potential in a myriad of applications including sewage treatment, food safety, humoral regulation, environmental and biological monitoring, and medical diagnosis.

High FOM PCF-SPR refractive index sensor based on MgF2-Au double-layer films.

A simple twin-core D-shape photonic crystal fiber sensor based on surface plasmon resonance (SPR) is designed for the measurement of refractive indices (RI). The twin-core D-shape structure enhances the SPR effect, and the M g F 2-Au dual-layer film narrows the linewidth in the loss spectrum, consequently improving both the sensitivity and figure of merit (FOM). The properties of the sensor are analyzed by the finite element method. In the RI range of 1.32-1.42, the maximum wavelength sensitivity, FOM, and resolution are 62,000 nm/RIU, 1281R I U -1, and 1.61×10-6, respectively.

Nickel foam-loaded Co-MOF@TiO2/MoS2 as electrode materials for dual-function devices for glucose detection and hydrogen evolution.

Dual-functional nanomaterial electrodes have the capability to satisfy the requirements for both sweat analysis and the hydrogen evolution reaction (HER), thereby enabling the integration of electrochemical sensing and hydrogen production. In this study, ZIF-67 cubes are synthesized on nickel foam (NF), while TiO2 is obtained through an annealing process. Subsequently, the ZIF-67@TiO2/MoS2 nanocomposite is fabricated on nickel foam via a hydrothermal method. This composite material exhibits exceptional photocatalytic properties and is also suitable for the detection of glucose in sweat. The glucose detection range spans from 10 nM to 10 mM with a sensitivity of 7.24 µA mM-1 cm-2 for a signal-to-noise ratio of 3 and a detection limit of 0.43 µM. Moreover, when utilized as a hydrogen evolution electrode, this material demonstrates a current density of 10 mA cm-2 at an overpotential of 118 mV, with a Tafel slope of 73 mV/dec. The synthesis process is both straightforward and economical. This research introduces a novel concept for the design of multifunctional chemical sensors.

Data-Driven Controlled Synthesis of Oriented Quasi-Spherical CsPbBr3 Perovskite Materials.

Controlled synthesis of lead-halide perovskite crystals is challenging yet attractive because of the pivotal role played by the crystal structure and growth conditions in regulating their properties. This study introduces data-driven strategies for the controlled synthesis of oriented quasi-spherical CsPbBr3, alongside an investigation into the synthesis mechanism. High-throughput rapid characterization of absorption spectra and color under ultraviolet illumination was conducted using 23 possible ligands for the synthesis of CsPbBr3 crystals. The links between the absorption spectra slope (difference in the absorbance at 400 nm and 450 nm divided by a wavelength interval of 50 nm) and crystal size were determined through statistical analysis of more than 100 related publications. Big data analysis and machine learning were employed to investigate a total of 688 absorption spectra and 652 color values, revealing correlations between synthesis parameters and properties. Ex situ characterization confirmed successful synthesis of oriented quasi-spherical CsPbBr3 perovskites using polyvinylpyrrolidone and Acacia. Density functional theory calculations highlighted strong adsorption of Acacia on the (110) facet of CsPbBr3. Optical properties of the oriented quasi-spherical perovskites prepared with these data-driven strategies were significantly improved. This study demonstrates that data-driven controlled synthesis facilitates morphology-controlled perovskites with excellent optical properties.

Dual elemental doping activated signaling pathway of angiogenesis and defective heterojunction engineering for effective therapy of MRSA-infected wounds.

Multi-drug resistant bacterial infections pose a significant threat to human health. Thus, the development of effective bactericidal strategies is a pressing concern. In this study, a ternary heterostructure (Zn-CN/P-GO/BiS) comprised of Zn-doped graphite phase carbon nitride (g-C3N4), phosphorous-doped graphene oxide (GO) and bismuth sulphide (Bi2S3) is constructed for efficiently treating methicillin-resistant Staphylococcus aureus (MRSA)-infected wound. Zn doping-induced defect sites in g-C3N4 results in a reduced band gap (ΔE) and a smaller energy gap (ΔEST) between the singlet state S1 and triplet state T1, which favours two-photon excitation and accelerates electron transfer. Furthermore, the formation of an internal electric field at the ternary heterogeneous interface optimizes the charge transfer pathway, inhibits the recombination of electron-hole pairs, improves the photodynamic effect of g-C3N4, and enhances its catalytic performance. Therefore, the Zn-CN/P-GO/BiS significantly augments the production of reactive oxygen species and heat under 808 nm NIR (0.67 W cm-2) irradiation, leading to the elimination of 99.60% ± 0.07% MRSA within 20 min. Additionally, the release of essential trace elements (Zn and P) promotes wound healing by activating hypoxia-inducible factor-1 (HIF-1) and peroxisome proliferator-activated receptors (PPAR) signaling pathways. This work provides unique insight into the rapid antibacterial applications of trace element doping and two-photon excitation.

Ca-doping interfacial engineering and glycolysis enable rapid charge separation for efficient phototherapy of MRSA-infected wounds.

Methicillin-resistant Staphylococcus aureus (MRSA) is the primary pathogenic agent responsible for epidermal wound infection and suppuration, seriously threatening the life and health of human beings. To address this fundamental challenge, we propose a heterojunction nanocomposite (Ca-CN/MnS) comprised of Ca-doped g-C3N4 and MnS for the therapy of MRSA-accompanied wounds. The Ca doping leads to a reduction in both the bandgap and the singlet state S1-triplet state T2 energy gap (ΔEST). The Ca doping also facilitates the two-photon excitation, thus remarkably promoting the separation and transfer of 808 nm near-infrared (NIR) light-triggered electron-hole pairs together with the built-in electric field. Thereby, the production of reactive oxygen species and heat are substantially augmented nearby the nanocomposite under 808 nm NIR light irradiation. Consequently, an impressive photocatalytic MRSA bactericidal efficiency of 99.98 ± 0.02 % is achieved following exposure to NIR light for 20 min. The introduction of biologically functional elements (Ca and Mn) can up-regulate proteins such as pyruvate kinase (PKM), L-lactate dehydrogenase (LDHA), and calcium/calmodulin-dependent protein kinase (CAMKII), trigger the glycolysis and calcium signaling pathway, promote cell proliferation, cellular metabolism, and angiogenesis, thereby expediting the wound-healing process. This heterojunction nanocomposite, with its precise charge-transfer pathway, represents a highly effective bactericidal and bioactive system for treating multidrug-resistant bacterial infections and accelerating tissue repair. STATEMENT OF SIGNIFICANCE: Due to the bacterial resistance, developing an antibiotic-free and highly effective bactericidal strategy to treat bacteria-infected wounds is critical. We have designed a heterojunction consisting of calcium doped g-C3N4 and MnS (Ca-CN/MnS) that can rapidly kill methicillin-resistant Staphylococcus aureus (MRSA) without damaging normal tissue through a synergistic effect of two-photon stimulated photothermal and photodynamic therapy. In addition, the release of trace amounts of biofunctional elements Mn and Ca triggers glycolysis and calcium signaling pathways that promote cellular metabolism and cell proliferation, contributing to tissue repair and wound healing.

Entropy-Driven Enhancement of the Conductivity and Phase Purity of Na4Fe3(PO4)2P2O7 as the Superior Cathode in Sodium-Ion Batteries.

Na4Fe3(PO4)2(P2O7) (NFPP) is regarded as a promising cathode material for sodium-ion batteries (SIBs) owing to its low cost, easy manufacture, environmental purity, high structural stability, unique three-dimensional Na-ion diffusion channels, and appropriate working voltage. However, for NFPP, the low conductivity of electrons and ions limits their capacity and power density. The generation of NaFeP2O7 and NaFePO4 inhibits the diffusion of sodium ions and reduces reversible capacity and rate performance during the manufacturing process in synthesis methods. Herein, we report an entropy-driven approach to enhance the electronic conductivity and, concurrently, phase purity of NFPP as the superior cathode in sodium-ion batteries. This approach was realized via Ti ions substituting different ratios of Fe-occupied sites in the NFPP lattice (denoted as NTFPP-X, T is the Ti in the lattice, X is the ratio of Ti-substitution) with the configurational entropic increment of the lattice structures from 0.68 R to 0.79 R. Specifically, 5% Ti-substituted lattice (NTFPP-0.05) inducing entropic augmentation not only improves the electronic conductivity from 7.1 × 10-2 S/m to 8.6 × 10-2 S/m but also generates the pure-phase of NFPP (suppressing the impure phases of the NaFeP2O7 and NaFePO4) of the lattice structure, which is validated by a series of characterizations, including powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). Benefiting from the Ti replacement in the lattice, the optimal NTFPP-0.05 composite shows a high first discharge capacity (118.5 mAh g-1 at 0.1 C), superior rate performance (70.5 mAh g-1 at 10 C), and excellent long cycling life (1200 cycles at 10 C with capacity retention of 86.9%). This research proposes a new entropy-driven approach to improve the electrochemical performance of NFPP and reports a low-cost, ultrastable, and high-rate cathode material of NTFPP-0.05 for SIBs.

Low-Temperature Plasma-Constructed Ni-Doped W18O49 Nanorod Arrays for Enhanced Electrocatalytic Oxygen Evolution and Urea Oxidation.

Surface engineering by doping and amorphization is receiving widespread attention from the perspective of the regulation of the electrocatalytic activities of electrocatalysts. However, the effective modulation of active sites on catalysts is still challenging. Herein, a straightforward and efficient method combining hydrothermal treatment with low-temperature plasma processing is presented to synthesize Ni-doped W18O49 nanorod arrays on carbon cloth with abundant oxygen vacancies (CC/WO-Ni-x). Mild plasma doping with Ni modifies the electronic structure of the W18O49 nanorod arrays, resulting in the formation of an amorphous structure that significantly reduces the electron transfer resistance. Additionally, the coupling with high-valent W6+ (derived from W18O49) leads to the partial preoxidation of doped Ni to form active Ni3+ species and oxygen vacancies. These features are collectively responsible for the remarkable oxygen evolution reaction (OER) and urea oxidation reaction (UOR) properties of CC/WO-Ni-4, for example, 10 mA cm-2 current density, an overpotential of 265 mV required for the OER under 1.0 M KOH solution. The addition of 500 mM urea to the 1.0 M KOH solution decreases the overpotential required for the same current density from 265 to 93 mV. This study provides insights into the modification of surface structures and presents an effective strategy to optimize the electrocatalytic active sites and enhance the efficiency of multifunctional electrocatalysts.

Multilevel Information Encryption Based on Thermochromic Perovskite Microcapsules via Orthogonal Photic and Thermal Stimuli Responses.

Increasing modal variations of stimulus-responsive materials ensure the high capacity and confidentiality of information storage and encryption systems that are crucial to information security. Herein, thermochromic perovskite microcapsules (TPMs) with dual-variable and quadruple-modal reversible properties are designed and prepared on the original oil-in-fluorine (O/F) emulsion system. The TPMs respond to the orthogonal variations of external UV and thermal stimuli in four reversible switchable modes and exhibit excellent thermal, air, and water stability due to the protection of perovskites by the core-shell structure. Benefiting from the high-density information storage TPMs, multiple information encryptions and decryptions are demonstrated. Moreover, a set of devices are assembled for a multilevel information encryption system. By taking advantage of TPMs as a "private key" for decryption, the signal can be identified as the corresponding binary ASCII code and converted to the real message. The results demonstrate a breakthrough in high-density information storage materials as well as a multilevel information encryption system based on switchable quadruple-modal TPMs.

Ultrasound-driven radical chain reaction and immunoregulation of piezoelectric-based hybrid coating for treating implant infection.

The poor efficiency of US-responsive coatings on implants restricts their practical application. Immunotherapy that stimulates immune cells to enhance their antibacterial activity is expected to synergize with sonodynamic therapy for treating implant infection effectively and safely. Herein, US-responsive hybrid coatings composed of the oxygen-deficient BaTiO3 nanorod arrays and l-arginine (BaTiO3-x/LA) are designed and prepared on titanium implants for sonocatalytic therapy-cooperated immunotherapy to treat Methicillin-resistant Staphylococcus aureus (MRSA) infection. BaTiO3-x/LA can generate more oxidizing reactive oxygen species (ROS, hydroxyl radical (·OH)) and reactive nitrogen species (RNS, peroxynitrite anion (ONOO-)). The construction of nanorod arrays and oxygen defects balances the piezoelectric properties and sonocatalytic capability during US treatment. The generated piezoelectric electric field provides a sufficient driving force to separate electrons and holes, and the oxygen defects attenuate the electron-hole recombination efficiency, consequently increasing the yield of ROS during the US treatment. Moreover, nitric oxide (NO) released by l-arginine reacts with the superoxide radical (·O2-) to produce ONOO-. Since, this radical chain reaction improves the oxidizing ability between bacteria and radicals, the cell membrane (argB, secA2) and DNA (dnaBGXN) are destroyed. The bacterial self-repair mechanism indirectly accelerates bacterial death based on the transcriptome analysis. In addition to participating in the radical chain reaction, NO positively affects macrophage M1 polarization to yield potent phagocytosis to MRSA. As a result, without introducing an extra sonosensitizer, BaTiO3-x/LA exhibits excellent antibacterial activity against MRSA after the US treatment for 15 min. Furthermore, BaTiO3-x/LA facilitates macrophage M2 polarization after implantation and improves osteogenic differentiation. The combined effects of sonodynamic therapy and immunoregulation lead to an effective and safe treatment method for implant-associated infections.

Porous VN nanosheet arrays on MXene carbon fibers for flexible supercapacitors.

VN usually has poor rate performance and cycle stability. In this work, porous VN nanosheet arrays were prepared on carbon nanofibers embedded with Ti3C2Tx nanosheets by electrospinning and chemical vapor deposition. The 3D network accelerates the transfer of electrons and electrolyte ions, prevents the aggregation of VN and the self-stacking of MXene, and enhances cycle stability. The solid-state flexible device comprising Co3O4, MXCF@VN, and KOH/PVA exhibits exceptional energy densities of 83.95 W h kg-1 and robust cycling stability (82.8% retention after 20 000 cycles).

Field-Effect Thermoelectric Hotspot in Monolayer Graphene Transistor.

Graphene is a promising candidate for the thermal management of downscaled microelectronic devices owing to its exceptional electrical and thermal properties. Nevertheless, a comprehensive understanding of the intricate electrical and thermal interconversions at a nanoscale, particularly in field-effect transistors with prevalent gate operations, remains elusive. In this study, nanothermometric imaging is used to examine a current-carrying monolayer graphene channel sandwiched between hexagonal boron nitride dielectrics. It is revealed for the first time that beyond the expected Joule heating, the thermoelectric Peltier effect actively plays a significant role in generating hotspots beneath the gated region. With gate-controlled charge redistribution and a shift in the Dirac point position, an unprecedented systematic evolution of thermoelectric hotspots, underscoring their remarkable tenability is demonstrated. This study reveals the field-effect Peltier contribution in a single graphene-material channel of transistors, offering valuable insights into field-effect thermoelectrics and future on-chip energy management.

Percolating Network of Anionic Vacancies in Prussian Blue: Origin of Superior Ammonium-Ion Storage Performance.

Emerging aqueous ammonium-ion batteries (AIBs) are considered inexpensive, highly safe, ecofriendly, and sustainable energy storage systems. Although some high-performance electrode materials have been reported for AIBs, a comprehensive understanding of the origin of the high ammonium-ion storage performance is still lacking. Herein, the percolating network of anionic vacancies is determined to be the origin of the superior ammonium-ion storage properties of the Prussian blue analogues based on ab initio molecular dynamics simulation and electrochemical kinetic analyses. Fe[Fe(CN)6] with a percolating anionic vacancy network delivers an outstanding rate of 64.7 mAh g-1 at 2000 mA g-1 in addition to a capacity retention of 94.5% after 10 000 cycles. The low-strain intercalation ammonium-ion storage mechanism of highly deficient Fe Prussian blue with Fe as the redox center is revealed by in situ X-ray diffraction and ex situ X-ray absorption fine structure analysis. The results provide insights into the mechanism of ammonium-ion storage in Prussian blue analogues and guidance in the development of aqueous AIBs.