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Metal-organic frameworks with tailorable coordination chemistry are propitious for regulating catalytic performance and deciphering genuine mechanisms. Herein, a linker compensation strategy is proposed to alter the intermediate adsorption free energy on the Co-Fe zeolitic imidazolate framework (CFZ). This grants zinc-air battery superior high current density capability with a small discharge-charge voltage gap of 0.88 V at 35 mA cm

Developing low-cost and high-efficiency bifunctional electrocatalysts for both oxygen evolution and reduction reactions is urgent to fulfill the practical application of rechargeable Zn-air batteries (ZABs). However, to explore the high catalytic performance of air electrocatalysts still remains a challenge. In response, a three-dimensionally ordered macroporous (3DOM) Co3O4 electrocatalyst is designed and synthesized through a nanocasting strategy. A well-controlled phosphorization treatment is further conducted to induce defect engineering on the resulting P-doped Co3O4–δ (3DOM P-Co3O4–δ). With the oxygen vacancy (Vo) tailoring, partial reduction from Co3+ to Co2+ is verified as the key to improving the intrinsic electrocatalytic bifunctionality. By incorporating the geometric and electronic merits, 3DOM P-Co3O4–δ possesses an ORR half-wave potential of 0.82 V and an OER overpotential of 366 mV to achieve 10 mA cm–2, which is comparable to noble-metal benchmarks. Particularly, under galvanostatic cycling measurements, ZABs using 3DOM P-Co3O4–δ containing air cathode showcase a potential gap of 0.84 V with negligible voltage fading over 250 h at 10 mA cm–2.

Electrochemical CO

The utilization of mildly acidic electrolyte and corresponding Mn salt pairing unlocked a path toward highly rechargeable Zn-MnO2 batteries, but long-term feasibility of these cathode-preserving strategy under practical conditions is never verified. In this study, in-situ MnO2 electrodeposition occurring in the battery recharging process is discovered to be a side reaction that substantially nullifies the practicality of the strategy. Particularly, it is identified to be responsible for irreversibly converting the electrolyte Mn ions to electrochemically passive species and triggering battery performance deterioration. These newfound recognitions lead to the formulation of a kinetic inhibition strategy, which is executed through an unconventional cathode electrode design. Specifically, graphite nanosheets with limited surface defects are incorporated into MnO2 electrodes to hinder the rate determining Mn adsorption process and thus effectively suppress the electrodeposition reaction. The resulting thin film binder-free MnO2 electrodes achieve near-full one-electron capacity reversibly for over 600 cycles, with an average columbic efficiency of ~99.8%. Overall, this study reveals the importance of suppressing MnO2 electrodeposition in Zn-MnO2 batteries and provides a contrasting view on key factors that dictate the stability of the system.

With the rapid development of flexible and wearable electronics, flexible zinc-air battery technology attracts ever-increasing attention and is considered as one of the most promising energy storage systems. However, its practical application is still at the preliminary stage. In this review, the basic battery configurations and design principles are discussed for flexible zinc-air battery, followed by challenges and recent progresses in developing each battery component, in terms of polymer electrolyte, metal anode and air cathode. An overview of flexible zinc-air battery is provided here with the aim to present a clear picture of current research directions.

The ability to extract/insert more than one Li per formula unit has made Li-rich layered oxides (LLO) one of the most promising cathode materials. However, irreversible transformations triggered by over-delithiation such as phase transitions, oxygen release and Jahn–Teller effects of Mn3+ have limited its practical application. In this work, the irreversible processes during repetitive de/lithiation were found to be diminished by establishing a gradient cationic redox couple of Mn3+/Mn4+ in Li1.2Ni0.2Mn0.6O2. As revealed by STEM, XPS and XAS measurements, the partial substitution of O2− by F− ions promoted nearby Li/transition metal mixing and reduced the valence state of Mn on the surface. Such a configuration shifted the surface redox center towards cationic redox couple (Mn3+/Mn4+), reducing the irreversible oxygen release as well as the ensuing structure and oxidation state changes. As a result of the modification, the product delivered a discharge capacity of 203.4 mA h g−1 after 80 cycles at 0.2C and achieved capacity retention of 89.6% after 100 cycles at 0.5C. The suppressed irreversible processes during repetitive cycling were investigated through ex situ X-ray absorption energy near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy and DFT calculations, which confirmed the well-preserved oxidation states and atomic configurations in modified Li1.2Ni0.2Mn0.6O2. Overall, this research provided a new avenue to control the irreversible processes in LLO without changing the anion redox behavior of lattice O2− in the bulk area by accommodating the cationic redox couple on the surface.

Understanding the bulk and interfacial behaviors during the operation of batteries (e.g., Li-ion, Na-ion, Li-O2 batteries, etc.) is of great significance for the continuing improvement of the performance. Electrochemical quartz crystal microbalance (EQCM) is a powerful tool to this end, as it enables in situ investigation into various phenomena, including ion insertion/deinsertion within electrodes, solid nucleation from the electrolyte, interphasial formation/evolution and solid-liquid coordination. As such, EQCM analysis helps to decipher the underlying mechanisms both in the bulk and at the interface. This tutorial review will present the recent progress in mechanistic studies of batteries achieved by the EQCM technology. The fundamentals and unique capability of EQCM are first discussed and compared with other techniques, and then the combination of EQCM with other in situ techniques is also covered. In addition, the recent studies utilizing EQCM technologies in revealing phenomena and mechanisms of various batteries are reviewed. Perspectives regarding the future application of EQCM in battery studies are given at the end.

Deploying the application of Au-based catalysts directly on CO2 reduction reactions (CO2 RR) relies on the simultaneous improvement of mass activity (usually lower than 10 mA mg-1Au at -0.6 V) and selectivity. To achieve this target, we herein manipulate the interface of small-size Au (3.5 nm) and CeO2 nanoparticles through adjusting the surface charge of Au and CeO2 . The well-regulated interfacial structure not only guarantees the utmost utilization of Au, but also enhances the CO2 adsorption. Consequently, the mass activity (CO) of the optimal AuCeO2 /C catalyst reaches 139 mA mg-1Au with 97 % CO faradaic efficiency (FECO ) at -0.6 V. Moreover, the strong interaction between Au and CeO2 endows the catalyst with excellent long-term stability. This work affords a charge-guided approach to construct the interfacial structure for CO2 RR and beyond.

Simultaneously improving energy efficiency (EE) and material stability in electrochemical CO2 conversion remains an unsolved challenge. Among a series of ternary Sn-Ti-O electrocatalysts, 3D ordered mesoporous (3DOM) Sn0.3 Ti0.7 O2 achieves a trade-off between active-site exposure and structural stability, demonstrating up to 71.5 % half-cell EE over 200 hours, and a 94.5 % Faradaic efficiency for CO at an overpotential as low as 430 mV. DFT and X-ray absorption fine structure analyses reveal an electron density reconfiguration in the Sn-Ti-O system. A downshift of the orbital band center of Sn and a charge depletion of Ti collectively facilitate the dissociative adsorption of the desired intermediate COOH* for CO formation. It is also beneficial in maintaining a local alkaline environment to suppress H2 and formate formation, and in stabilizing oxygen atoms to prolong durability. These findings provide a new strategy in materials design for efficient CO2 conversion and beyond.

Zn-based electrochemistry has recently been considered as the most promising family to challenge the dominant status of Li-based battery technologies. Besides its more abundant reserves, the modera...

The notorious shuttling behaviors and sluggish conversion kinetics of the intermediate lithium polysulfides (LPS) are hindering the practical application of lithium sulfur (Li-S) batteries. Herein, an ultrafine, amorphous, and oxygen-deficient niobium pentoxide nanocluster embedded in microporous carbon nanospheres (A-Nb2O5-x@MCS) was developed as a multifunctional sulfur immobilizer and promoter toward superior shuttle inhibition and conversion catalyzation of LPS. The A-Nb2O5-x nanocluster implanted framework uniformizes sulfur distribution, exposes vast active interfaces, and offers a reduced ion/electron transportation pathway for expedited redox reaction. Moreover, the low crystallinity feature of A-Nb2O5-x manipulates the LPS chemical affinity, while the defect chemistry enhances the intrinsic conductivity and catalytic activity for rapid electrochemical conversions. Attributed to these superiorities, A-Nb2O5-x@MCS delivers good Li-S battery performances, that is, high areal capacity of 6.62 mAh cm-2 under high sulfur loading and low electrolyte/sulfur ratio, superb rate capability, and cyclability over 1200 cycles with an ultralow capacity fading rate of 0.024% per cycle. This work provides a synergistic regulation on crystallinity and oxygen deficiency toward rapid and durable sulfur electrochemistry, holding a great promise in developing practically viable Li-S batteries and enlightening material engineering in related energy storage and conversion areas.

Understanding the bulk and interfacial behaviors during the operation of batteries (

The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries.

Ultramicroporous carbon materials play a critical role in CO2 capture and separation, however facile approaches to design ultramicroporous carbon with controllable amount, ratio and size of pores are still challenging. Herein, a novel strategy to design carbon nanospheres with abundant, uniform, and tunable ultramicroporosity was developed based on an in-situ ionic activation methodology. The adjustable ion-exchange capacity derived from oxidative functionalization was found capable of substantially governing the ionic activation and precisely regulating the ultramicroporosity in the resultant product. An ultrahigh ultramicropore content of 95.5% was achieved for the optimally-designed carbon nanospheres, which demonstrated excellent CO2 capture performances with extremely high capacities of 1.58 mmol g−1 at typical flue gas conditions and 4.30 mmol g−1 at 25 °C and ambient pressure. Beyond that, the CO2 adsorption mechanism in ultramicropore was also investigated through molecular dynamics simulation to guide the pore size optimization. This work provides a novel and facile guideline to engineer carbon materials with abundant and tunable ultramicroporosity towards superior CO2 capture performance, which also delivers great potential in extensive applications such as water purification, catalysis, and energy storage.

Here, we report an efficient surface decorated, e.g. oxidation and nitrogen doped, cobalt sulfide (O-N-Co9S8) oxygen electrocatalyst, which shows excellent activity especially for oxygen evolution reaction (OER), and good stability over 900 charge-discharge cycles at 10 mA cm−2 in Zinc-air battery. Moreover, we found that O-N-Co9S8 was completely converted into Co3O4 after OER, showing oxide is actual active phase. Density functional theory calculations reveal the continuous exposure of oxidized surface Co sites during O-N-Co9S8 → Co3O4 is essential for its high OER activity. These Co sites promote the kinetics for OH∗ transformation to O∗ and also ensure fast O2 desorption. Once Co3O4 is generated, the high activity is contributed by its resulting characteristic surfaces. Thus, we propose and demonstrate that oxides in-situ generated during OER are more active than the directly calcined oxides. This work advances fundamental insight of metal chalcogenides “catalysts” and guides the design of active OER catalysts.

Mn and N codoped carbon materials are proposed as one of the most promising catalysts for the oxygen reduction reaction (ORR) but still confront a lot of challenges to replace Pt. Herein, a novel gas-phase migration strategy is developed for the scale synthesis of atomically dispersed Mn and N codoped carbon materials (g-SA-Mn) as highly effective ORR catalysts. Porous zeolitic imidazolate frameworks serve as the appropriate support for the trapping and anchoring of Mn-containing gaseous species and the synchronous high-temperature pyrolysis process results in the generation of atomically dispersed Mn-N

Summary Metal organic framework (MOF) derivatives have been extensively used as bifunctional oxygen electrocatalysts. However, the utilization of active sites is still not satisfactory owing to the sluggish mass transport within their narrow pore channels. Herein, interconnected macroporous channels were constructed inside MOFs-derived Co-Nx-C electrocatalyst to unblock the mass transfer barrier. The as-synthesized electrocatalyst exhibits a honeycomb-like morphology with highly exposed Co-Nx-C active sites on carbon frame. Owing to the interconnected ordered macropores throughout the electrocatalyst, these active sites can smoothly “exhale/inhale” reactants and products, enhancing the accessibility of active sites and the reaction kinetics. As a result, the honeycomb-like Co-Nx-C displayed a potential difference of 0.773 V between the oxygen evolution reaction potential at 10 mA cm−2 and the oxygen reduction reaction half-wave potential, much lower than that of bulk-Co-Nx-C (0.842 V). The rational modification on porosity makes such honeycomb-like MOF derivative an excellent bifunctional oxygen electrocatalyst in rechargeable Zn-air batteries., Graphical Abstract, Highlights • A deep-breathing oxygen electrocatalyst with highly dispersed active sites was built • Sculpturing ordered macropores in MOF derivatives enables fast mass transport • The honeycomb-like Co-Nx-C nanopolyhedron worked well in rechargeable Zn-air battery, Catalysis; Inorganic Materials; Electrochemical Energy Storage.

Added risk portended by diabetes in addition to hypertension has been related to an amplification of endothelial dysfunction. β-blockers are widely used for cardiovascular diseases and improve the endothelial function compared with a placebo. However, the effect of β-blockers on the endothelial progenitor cells (EPCs) function in diabetes is still unknown. Five β-blockers (metoprolol, atenolol, propranolol, bisoprolol, and nebivolol) were tested in EPC functional screening. Metoprolol improved EPC function significantly among the five β-blockers and was chosen for the in vivo tests in STZ induced diabetic mice. Reactive hyperemia peripheral arterial tonometry (RH-PAT) measurements were performed using the Endo-PAT2000 device in diabetic patients. Metoprolol, but not other β-blockers, improved EPC function in both tube formation and migration assay. EPC function was significantly decreased in diabetic mice, and metoprolol treatment restored damaged EPC migration capabilities and circulation EPC number. Metoprolol treatment promoted wound healing and stimulated angiogenesis in diabetic mice. Furthermore, metoprolol significantly enhanced eNOS phosphorylation and decreased O2− levels in EPCs of diabetic mice. In clinical trials, the RH-PAT index was significantly higher in metoprolol-treated versus bisoprolol-treated diabetics. Metoprolol could accelerate wound healing in diabetic mice and improve endothelial function in diabetic subjects, which may be mediated in part by improving impaired EPC function.

The implementation of pristine metal-organic frameworks as air electrode may spark fresh vitality to rechargeable zinc-air batteries, but successful employment is rare due to the challenges in regulating their electronic states and structural porosity. Here we conquer these issues by incorporating ligand vacancies and hierarchical pores into cobalt-zinc heterometal imidazole frameworks. Systematic characterization and theoretical modeling disclose that the ligand editing eases surmountable energy barrier for *OH deprotonation by its efficacy to steer metal d-orbital electron occupancy. As a stride forward, the selected cobalt-zinc heterometallic alliance lifts the energy level of unsaturated d-orbitals and optimizes their adsorption/desorption process with oxygenated intermediates. With these merits, cobalt-zinc heterometal imidazole frameworks, as a conceptually unique electrode, empowers zinc-air battery with a discharge-charge voltage gap of 0.8 V and a cyclability of 1250 h at 15 mA cm–2, outperforming the noble-metal benchmarks., Low intrinsic activity and accessibility of active sites limit the application of metal-organic framework as catalyst for Zn-air battery. Here, authors present a cation substitution strategy to regulate the electronic state of metal sites and modify its porosity, which enables battery operation.

The notorious shuttling behaviors and sluggish conversion kinetics of the intermediate lithium polysulfides (LPS) are hindering the practical application of lithium sulfur (Li-S) batteries. Herein, an ultrafine, amorphous, and oxygen-deficient niobium pentoxide nanocluster embedded in microporous carbon nanospheres (A-Nb

Background/Aims: Peptidyl-prolyl cis-trans isomerase FKBP25 is a member of the FK506-binding proteins family which has peptidyl-prolyl cis/trans isomerase domain. The biological function and pathophysiologic role of FKBP25 remain elusive. Methods: The spatio-temporal changes in expression of endothelial FKBP25 upon oxygen-glucose deprivation (OGD) treatment were examined by Western blot and immunofluorescence. The immunoprecipitation and fluorescence resonance energy transfer (FRET) were used to address the interacting proteins with FKBP25. Results: In the present study, nuclear translocation of FKBP25 was observed following OGD in cultured endothelial cells. Intriguingly, FKBP25 nuclear translocation was further validated in peroxynitrite (ONOO-)-treated endothelial cells. Coimmunoprecipitation and FRET data indicated that FKBP25 translocated into the nucleus, in which it interacted with 60S ribosomal protein L7a, while overexpression FKBP25 protect endothelial cells against OGD injury. Conclusion: Our findings reveal that the nuclear import of FKBP25 and binding with 60S ribosomal protein L7a are protective stress responses to ischemia/nitrosaive stress injury.

The rational design of cathode host materials is significant in fulfilling high-efficiency sulfur electrochemistry as well as boosting the energy density of lithium–sulfur (Li–S) batteries. Herein, we develop a stringed “tube on cube” nanohybrid (CPZC) with a ternary hierarchical architecture, which contains a fibrous carbon skeleton, highly porous carbon cube filler, and abundant CNT tentacles as an advanced matrix for sulfur electrodes. The as-developed CPZC delivers excellent conductivity, abundant active interfaces, and strong confinement to polysulfide, and thus is capable of significantly expediting the sulfur redox kinetics and promoting battery durability. The fabricated sulfur electrode achieves a superb rate capability up to 10C, outstanding cyclability over 2000 cycles, and more importantly, excellent performance under high a sulfur loading and sparing electrolyte with a high energy density of 348.8 W h kg−1 and 327.6 W h L−1 at the system level, which reveals its potential in promoting the practical application of Li–S batteries.

It is still an urgent but challenging task to rational design metal organic frameworks (MOFs)-derived architectures with decent oxygen bifunctionality and durability on substrates for the development of flexible Zn-air batteries (ZABs). Herein, unique yolk-shelled microcages with Co-Nx-C decorations (Co-Nx-YSC) are designed and fabricated on carbon cloth (CC) through a proposed self-assembly strategy. Prior to assembly on carbon-based substrates pretreated with negative charge, the cationic modified colloidal MOFs with controllable morphology and composition were synthesized. After calcination of the obtained ZIF-67/CC under 600 °C, the flexible electrode Co-Nx-YSC-600/CC is obtained, which exhibits excellent oxygen bifunctionality, good cycling stability (400 cycles at 10 mA cm−2) and outstanding flexibility when directly employed as air electrode in flexible ZABs. Such yolk-shelled architecture not only optimizes the reactants availability towards active sites, but also provides capacious spaces for oxygen reactions and the corresponding mass transportation. Besides, the interconnected carbon nanotube frameworks can further ensure fast charge transfer and serve as the robust host for Co-Nx-C active sites. With these structural merits, Co-Nx-YSC-600/CC showcases its promises as air electrode for flexible ZABs.

Increasing both catalytic site accessibility and intrinsic activity of multishelled materials is critical to boost its efficiency for bifunctional oxygen electrocatalysis and initiate its application in metal–air batteries. Herein, a hierarchical porous double-shelled (Mg,Co)3O4 electrocatalyst with controllable Mg substitution is synthesized via a proposed in situ coordinating process. The hierarchical porosity optimizes the availability of active sites and broadens diffusion channels for oxygen species. Meanwhile, Mg substitution greatly increases electrical conductivity and realizes novel insight of tailoring lattice alkalinity. Specifically, Mg substitution positively influences oxygen electrocatalysis by inducing lattice buffer zones that promote hydroxyl detachment from nearby catalytic sites. As a result, the final hybrid of (Mg,Co)3O4 encapsulated in N-doped graphitized carbon affords superior bifunctional oxygen electrocatalytic activities, outperforming state-of-the-art noble-metal benchmarks. W...

Wound healing impairment is increasingly recognized to be a consequence of hyperglycemia-induced dysfunction of endothelial precursor cells (EPCs) in type 2 diabetes mellitus (T2DM). Metformin exhibits potential for the improvement of endothelial function and the wound healing process. However, the underlying mechanisms for the observed beneficial effects of metformin application remain to be completely understood. The present study assessed whether metformin, a widely used therapeutic drug for T2DM, may accelerate wound closure in T2DM db/db mice. Genetically hyperglycemic db/db mice were used as the T2DM model. Metformin (250 mg/kg/day; intragastric) was administered for two weeks prior to EPC collection and wound model creation in db/db mice. Wound healing was evaluated by alterations in the wound area and the number of platelet endothelial cell adhesion molecule-positive cells. The function of the isolated bone marrow-derived EPCs (BM-EPCs) was assessed by a tube formation assay. The number of circulating EPCs, and the levels of intracellular nitric oxide (NO) and superoxide (O2−) were detected by flow cytometry. Thrombospondin-1 (TSP-1) expression was determined by western blot analysis. It was observed that treatment with metformin accelerated wound healing, improved angiogenesis and increased the circulating EPC number in db/db mice. In vitro, treatment with metformin reversed the impaired BM-EPC function reflected by tube formation, and significantly increased NO production while decreasing O2− levels in BM-EPCs from db/db mice. In addition, TSP-1 expression was markedly attenuated by treatment with metformin in cultured BM-EPCs. Metformin contributed to wound healing and improved angiogenesis in T2DM mice, which was, in part, associated with stimulation of NO, and inhibition of O2− and TSP-1 in EPCs from db/db mice.

Inspired by the excellent absorption capability of spongelike bacterial cellulose (BC), three-dimensional hierarchical porous carbon fibers doped with an ultrahigh content of N (21.2 atom %) (i.e., nitrogen-doped carbon fibers, NDCFs) were synthesized by an adsorption–swelling strategy using BC as the carbonaceous material. When used as anode materials for sodium-ion batteries, the NDCFs deliver a high reversible capacity of 86.2 mAh g–1 even after 2000 cycles at a high current density of 10.0 A g–1. It is proposed that the excellent Na+ storage performance is mainly due to the defective surface of the NDCFs created by the high content of N dopant. Density functional theory (DFT) calculations show that the defect sites created by N doping can strongly “host” Na+ and therefore contribute to the enhanced storage capacity.

In this work, a composite consisting of layered Li[Li0.2Ni0.12 Mn0.56Co0.12]O2 (LNMC) and spinel Li[Ni0.5Mn1.5]O4 (LNMO) was synthesized by a modified Pechini method. Extensive analysis was carried out to investigate the synergistic effect between the layered oxide and spinels in the composite by comparing its properties with baseline individual compounds, as well as a physical mixture of LMNC and LNMO. Comparing to the LNMC, the compsoite cathode exhibited a similar initial capacity of ∼250 mA·h/g at 0.1 C, but a much higher first-cycle effeciency, better cyclability and rate capability, attributed to the presence of spinel. The synertistic effect of integrated spinel on the microstructure, crystal strucutre, Mn oxidation states, and Li+/Ni2+ disordering of the composite was studied by X-ray absorption near edge structure (XANES), electron microscopy, and X-ray diffraction (XRD). The presence of a spinel component in the composite cathode is the origin for the improvement of cyclability and rate capabili...

In this article, we report improved capacity retention in lithium-sulfur (Li-S) batteries by replacing the conventional Polyvinylidene fluoride (PVDF) binder with inexpensive guar gum (GG). The S/GG cathode exhibits a discharge capacity of 777 mAh g−1 at 0.2 C after 150 cycles, in comparison to 491 mAh g−1 of S/PVDF cathode. FTIR results show that there is interaction between GG and sulfur species. This interaction is potentially capable of maintaining the active sulfur species, which could to a certain extent inhibit shuttling effect. What's more, GG shows limited dissolving and swelling capacity in the electrolyte and higher viscosity and hardness than those of PVDF. Such properties of GG provide the electrode with appropriate extensibility to alleviate the negative impact from the volume variation. Keywords: Lithium-sulfur batteries, Guar gum, Aqueous binder, Cycleability

The poor durability of bifunctional oxygen electrocatalysts is one main bottleneck that suppresses the widespread application of rechargeable metal-air batteries. Herein, a "ship in a bottle" design is achieved by impregnating fine transition metal dichalcogenide nanoparticles into defective carbon pores that act as interconnected nanoreactors. The erected 3D porous conductive architecture provides a "highway" for expediting charge and mass transfer. This design not only delivers a high surface-to-volume ratio to increase numbers of exposed catalytic sites but also precludes nanoparticles from aggregation during cycling owing to the pore spatial confinement effect. Therefore, the long-term plague inherent to nanocatalyst stability can be solved. Moreover, the synergistic coupling effects between defect-rich interfaces and chemical bonding derived from heteroatom-doping boost the catalytic activity and prohibit the detachment of nanoparticles for better stability. Consequently, the developed catalyst presents superior bifunctional oxygen electrocatalytic activities and durability, out-performing the best-known noble-metal benchmarks. In a practical application to rechargeable Zn-air batteries, long-term cyclability for over 340 h is realized at a high current density of 25 mA cm-2 in ambient air while retaining an intact structure. Such a universal "ship in a bottle" design offers an appealing and instructive model of nanomaterial engineering for implementation in various fields.

The first-cycle behavior of layered Li-rich oxides, including Li