Oxygen non-stoichiometry is a central state variable in mixed-conducting complex oxides because it simultaneously perturbs lattice dimensions, transition-metal valence, carrier transport, interfacial charge transfer, and the density of oxygen-related surface states. Yet materials studies often assess these responses one at a time, making it difficult to distinguish the total effect of oxygen deficiency from transport-mediated pathways and to identify a defensible operating window. This study develops a regression-centered structure–property–performance framework using La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃-δ (LSCF) as a model perovskite. A 96-observation development design spans six annealing temperatures and four oxygen activities. HC3-robust multivariable regressions link δ to crystal chemistry, transport, OER overpotential at 10 mA cm⁻² (η₁₀), Tafel slope, and 10 h retention. The strongest result is a highly significant nonlinear η₁₀ response: introducing δ² raises adjusted R² from 0.474 to 0.824, and adding conductivity and charge-transfer resistance increases adjusted R² to 0.920 while reducing RMSE to 3.37 mV. In the transport-conditioned model, centered δ remains negative (β = -193.19, p = 0.003), δ² is positive (β = 2168.83, p < 0.001), conductivity lowers η₁₀ (β = -0.800, p < 0.001), and Rct raises η₁₀ (β = 0.603, p < 0.001). The model-implied minimum occurs near δ = 0.152, with a bootstrap interval of 0.129–0.187. Parallel regressions show comparable curvature for Tafel kinetics and an inverted-U relation for durability. Robust, median, and bootstrap estimators preserve the principal coefficient signs. The framework therefore treats oxygen non-stoichiometry not as a monotonic defect descriptor but as a coupled design variable whose catalytic benefit depends on transport and structural strain.

MnMoO4 holds great promise as a cathode material for lithium-oxygen batteries (LOBs), but its poor conductivity and weak interaction with oxygenated intermediates substantially impede its electrocatalytic properties. Herein, electron-deficient P atoms were incorporated with MnMoO4 hollow nanospheres (P-doped MnMoO4) to realize internal orbital interactions between Mo 4d and P 3p, activating external orbital hybridization between catalysts and LiO2 during cycling. This relay orbital hybridization not only promoted charge transfer but also optimized the adsorption and desorption abilities of catalysts toward LiO2, thereby reducing the reaction energy barriers. Consequently, LOBs with P-doped MnMoO4 cathode catalysts sustained steady operation for 380 cycles under 1000 mA g-1 , which is even better than some of their noble metal counterparts and points to their commercial promise for use in future large-scale applications. This work provides general guidance for constructing relay orbital hybridization through P doping on catalysts for LOBs and other electrocatalytic systems.

To address the urgent demand for carbon-based microwave absorbing materials that combine low weight, high efficiency, and broad bandwidth in complex electromagnetic environments, this study proposes a component-coupling strategy assisted by wet spinning technology for the fabrication of HEAs/PAN-derived carbon composite fibers. Subsequent stabilization and carbonization treatments generate a hierarchical porous fiber structure featuring embedded alloy/carbon heterointerfaces. The resulting fibers integrate a continuous carbon framework, accessible mesoporous channels, and uniformly distributed metallic domains, which collectively facilitate electromagnetic wave penetration and dielectric attenuation. Among the samples investigated, P2H2-700 exhibits the optimal overall absorption performance, achieving a minimum reflection loss of − 50.37 dB at 13.12 GHz with a thickness of 2.7 mm, and an effective absorption bandwidth of 6.77 GHz at 2.67 mm. Electromagnetic analysis reveals that the absorption characteristics are governed primarily by conduction loss along the interconnected carbon framework and polarization relaxation associated with alloy/carbon interfaces and defect-containing carbon regions, while the porous fiber structure further prolongs propagation paths through multiple scattering and reflections. Density functional theory calculations performed on a representative alloy/carbon interface support the presence of interfacial charge redistribution, which is consistent with the observed enhancement in interfacial polarization. This work demonstrates a wet spinning approach to tailor the architecture of PAN-derived carbon fibers and the embedded alloy/carbon interfaces for broadband electromagnetic wave absorption.

Lithium-sulfur (Li-S) batteries are regarded as promising candidates for next-generation high-energy storage systems due to their superior theoretical capacity. However, their commercial application is severely constrained by the polysulfide shuttle effect and slow reaction kinetics. This study synthesized a g-C3N4-based heterostructured separator modification material, g-C3N4-MoS2/VS2 (MoVSCN), via a two-step hydrothermal method. The material not only facilitates spontaneous electron redistribution at the ternary interfaces, forming an internal electric field and abundant defect sites for effective adsorption and catalysis of polysulfides, but also achieves a synergistic optimization of electron and ion transport pathways, thereby significantly enhancing the overall reaction kinetics and cycling stability of lithium-sulfur batteries. Electrochemical testing indicates that the modified battery exhibits high capacity (1353 mAh g-1 during initial discharge at 0.2 C), excellent rate performance (721 mAh g-1 at 5 C), and exceptionally long lifespan (capacity decay rate of only 0.048% after 1000 cycles at 1 C). Even under low-temperature conditions (0 degrees C), the battery maintains a high specific capacity of 1160.7 mAh g-1 and an impressive capacity retention of 83.6%. The morphology of the lithium anode after cycling demonstrates its ability to nearly completely suppress the shuttle effect. These findings lay a solid foundation for pioneering advances in ternary composite materials and heterostructure interface engineering.

The fabrication of highly efficient and stable non-noble metal hydrogen evolution reaction (HER) electrocatalysts is of paramount significance for alleviating the energy and environmental crises. Herein, nickel (Ni) nanoparticles anchored on a carbon layer dispersed on carbon materials (Ni/C) are synthesized via a facile one-step thermal treatment. The nanostructure can facilitate mass transfer, expose more active sites and promote hydrogen (H2) gas release. Benefiting from these advantages, Ni/C-0.8 exhibits excellent electrocatalytic HER performance. The overpotential of Ni/C-0.8 is -132 mV at -10 mA cm-2, and its Tafel slope is 117 mV dec-1 in an alkaline solution. Additionally, Ni/C-0.8 exhibits remarkable stability during long-term testing. This work offers a new avenue for designing and fabricating non-noble metal electrocatalysts for the electrocatalytic HER.

Li metal anode shows significant potential for advancing high-energy-density and commercially viable lithium batteries due to its high specific capacity and low electrochemical potential. However, thinning Li metal encounters serious challenges owing to its mechanical stickiness and fragility during the mechanical rolling process, which severely restricts its practical utilization. Consequently, most current Li metal batteries rely on excessively thick Li foils, leading to substantial resource waste and undermining the pursuit of high energy density. This review highlights the quantitative design principles of ultrathin Li metal (≤15 µm) and elucidates its critical roles in realizing the true potential of Li metal batteries. Emerging strategies for the fabrication of ultrathin Li metal, followed by a critical evaluation of recent advances and persistent challenges in their deployment for both liquid and solid-state batteries, are summarized. A perspective on future directions for ultrathin Li metal is also presented. Ultrathin Li metal anodes are poised to deliver transformative improvements in energy density, unlocking new opportunities for advanced energy storage systems.

High-energy-density lithium-sulfur batteries (LSBs) are promising next-generation energy storage systems but face challenges such as the polysulfide shuttle effect and sluggish reaction kinetics, leading to poor sulfur utilization and short cycle life. This study employed theoretical calculations to evaluate group VIII metal disulfides (MS2, M = Fe, Co, Ni) as sulfur host materials. Results indicated FeS2 exhibits stronger adsorption for lithium polysulfides (LiPSs) due to synergistic S-S covalent bonds and Fe-S coordination. Based on these insights, SMS2@KBCNT composites were synthesized as cathodes. Electrochemical tests demonstrated that the SFeS2@KBCNT cathode exhibited outstanding long-cycle performance, maintaining excellent cycling stability with a capacity decay rate of only 0.0564 % per cycle over 1,200 cycles at a current density of 0.5C. Even at 2C, it maintained structural stability and high discharge capacity, outperforming CoS2 and NiS2 counterparts. Adsorption experiments confirmed FeS2's strong affinity for LiPSs. Furthermore, FeS2 mitigates the shuttle effect and enhances redox kinetics by facilitating electron/ion transport. This study provides valuable guidance for designing high-performance sulfur hosts with suppressed shuttle effects in LSBs.

ABSTRACT Rechargeable Li–O 2 batteries have attracted significant attention as a next‐generation energy storage technology because of their extremely high theoretical energy density. However, practical implementation remains hindered by limited energy density, poor cycling stability, pronounced parasitic reactions, and elevated overpotentials. Using zeolitic imidazolate frameworks (ZIFs) as templates, MoS 2 @NiCo 2 S 4 heterostructures were formed in situ via conversion to bimetallic layered double hydroxides, and the resulting hollow architecture was assembled from MoS 2 and NiCo 2 S 4 nanosheets. MoS 2 @NiCo 2 S 4 cathodes deliver remarkable discharge/charge specific capacities of 12412/11453 mAh g −1 at 100 mA g −1 and enhanced cycling stability over 208 cycles at 500 mA g −1 in Li–O 2 batteries. The improved performance of MoS 2 @NiCo 2 S 4 is mainly due to strong interactions between these two phases, with a hollow, porous structure that enhances regulation of reaction intermediates and enables precise control over electrochemical pathways during charging and discharging. Specifically, uniform formation and efficient decomposition of conformal Li 2 O 2 films were facilitated, and detrimental issues were effectively eased, resulting in improved reaction kinetics, enhanced capacity retention, and extended cycling stability. These findings highlight the great potential of MoS 2 @NiCo 2 S 4 heterostructures for applying in research fields of advanced energy storage and conversion, presenting a promising strategy for next‐generation energy technologies.

The growing demand for high-performance microwave-absorbing materials drives efforts to reduce electromagnetic pollution and advance stealth technologies. This study reports the synthesis of carbon nanofibers embedded with CoFe-CoFe2O4 nanoparticles (CoFe-CoFe2O4@C), referred to as MCNFs, synthesized via the electrospinning method. The composition, morphology, and microwave absorption (MA) properties of the composites were systematically studied by various characterization techniques. The research aims to enhance the microwave absorption performance of the fabricated nanofibers and investigate the absorption behavior at varied filler loadings (10-25 wt%) in a paraffin matrix. The results reveal that the synthetic MCNFs have excellent absorption at all given filler contents, and an optimal performance is obtained at 20% filler. For this weight percentage, MCNFs-1 exhibited a minimum reflection loss (RLmin) of-68.07 dB with a broad effective absorption bandwidth (RL <=-10 dB) EAB of 5.3 GHz at a matching thickness of 4.81 mm. Notably, with a reduced thickness of 1.48 mm, the MCNFs-4 obtains an RLmin=-49.97 dB, maintaining a wide EAB of 5.6 GHz. The Fe/Co molar ratios (3:7-7:3) have a devastating influence on electromagnetic parameters whereby optimized ratios improve magnetic-dielectric synergy and interfacial polarization. The synergistic effect of CoFe-CoFe2O4 nanoparticles in carbon nanofiber networks results in excellent MA properties, including perfect impedance matching and effective microwave attenuation. The analysis shows that MCNFs are effective and lightweight microwave absorbers for electromagnetic shielding, stealth, and radar wave detection.

Li-O2 batteries with high theoretical energy density are limited by low kinetics due to the insulating discharge product, which passivates the cathode surface, and hindering oxygen reduction/evolution reactions (ORR/OER). Herein, methylamine-intercalated MoS2 (MIMS) nanoflowers were synthesized and applied as the cathode to promote the catalytic reactions of Li-O2 batteries. The introduction of electron-rich methylamine facilitates charge injection into Mo 4d orbitals of MoS2, triggering its phase transition from 2H to 1T. This results in an elevated d-band center to enhance the adsorption energies toward key intermediate LiO2, boosting formation of film-like Li2O2. In situ EIS data combined with distribution of relaxation times (DRT) and distribution of capacitive times (DCT) analyses reveal the distinct electrocatalytic mechanisms of MIMS and MS cathodes, effectively illustrating the enhanced capacitive contribution and reduced interfacial impedance induced by dynamic oxygen intermediate evolution at the electrochemical interfaces on MIMS cathodes. The resultant Li-O2 batteries show a reduced voltage gap (0.85 V), high discharge/charge capacities (19083/18839 mAh g-1), and long-term stability (620 cycles at 1000 mA g-1). Besides, the fabricated pouch cells deliver a high energy density of 726.7 Wh kg-1 and stable operation over 1000 h, showing promise for practical use. These findings demonstrate the contribution of intercalation to the regulation of the interfacial chemistry and electrochemical performance of Li-O2 batteries.

The development of high-efficiency ion transport membranes is of great importance in the fields of energy, water purification and resource recovery. In the application of lithium extraction from salt lakes, membranes dominated by size sieving and Donnan exclusion typically enhance Li+/Mg2+ selectivity by sacrificing Li+ flux, which inevitably increases the energy consumption of the separation dramatically. In this work, we manipulate the pore charge density to demonstrate the important role of counterion-mediated positively charged channels in efficient Li+ transport. The potential relationship between the transport behaviour of cations and the membrane charge density was revealed after decoupling the transport of anions and cations using the electric field. On the basis of Manning’s counterion condensation theory and density functional theory calculations, the transport mode in monovalent cations by interacting with the anchored counterions in the positively charged pores to form a high-velocity transport pathway is revealed. The cationic covalent organic framework membranes displayed high Li+/Mg2+ selectivity of 321 in electrodialysis tests while possessing superior lithium permeation rates (0.53 mol m−2 h−1). Therefore, our results suggest that counterion-mediated covalent organic framework membranes have great potential in the field of lithium resource extraction. The counterion-mediated positively charged channels in covalent organic framework membranes enable the fast transport of lithium ions, realizing high lithium/magnesium selectivity without compromising lithium ion flux.

Vanadium-based catalysts are considered an effective strategy to resolve the shuttle effect and sluggish solid-liquid-solid reaction kinetics in lithium-sulfur (Li-S) batteries, thanks to their strong adsorption and catalytic conversion capabilities toward polysulfides. Herein, a self-oxidation-driven solvothermal strategy was employed to construct a defect-rich homologous heterostructure of nanoflower-like VS2-VOx on a two-dimensional conductive V2C network (denoted as VSOC). The experimental results demonstrate that VSOC effectively enhances the multiphase redox reaction kinetics of sulfur species through the strong adsorption and spontaneous transformation of long-chain polysulfides by the highly conductive V2C and the accelerated catalytic reduction of insoluble short-chain Li2S by the V-S-O heterostructure. Consequently, the Li-S cells assembled with VSOC-modified separator and normal loaded 1.0 mg cm(-2) KB/S cathode deliver a high first discharge capacity of 1340 mAh g(-1) at 0.2 C with a low-capacity decay rate of 0.03% per cycle during long-term cycling at 1 C. It still achieves a capacity contribution of 501.3 mAh g(-1) even at 5 C. Moreover, under challenging conditions such as high sulfur loading (4.2 mg cm(-2)) and low temperature (0 degrees C), the VSOC-modified separator maintains 89% and 85% capacity retention and stable Coulombic efficiency. This study proposes a novel heterostructure design strategy for optimizing the performance of Li-S batteries.

To develop effective electrocatalysts, the d-band center theory has been a reliable predictor of electrocatalytic activity in transition-metal-based catalysts. However, it fails to accurately describe magnetic systems influenced by spin polarization. Herein, phosphorus doping was introduced into cobalt diselenide on a hive-like carbon framework with nitrogen insertion (P-CoSe2@NC), which significantly enhances electrocatalytic performance for reversible CO2 conversion in an advanced Li-CO2 battery with specific capacities around 17,000 mAh g-1, high-rate performance, and good longevity exceeding 600 h in a pouch cell. Phosphorus doping induces lattice torsion in CoSe2, leading to strain-caused changes in the d-band center across different crystal planes, which are linked with the redistribution of spin states. To address the limitations of the traditional single d-band center model, the dual center model reveals how phosphorus doping effectively harmonizes the competition between spin orbitals, originating from changes in higher spin states. Such equilibrium moderates interactions with electrochemical intermediates to lower reaction energy barriers, enhancing reversible electrocatalysis for Li-CO2 batteries. Therefore, strain-induced changes in the d-band centers, coupled with alterations in spin states, underline the enhanced electrocatalytic performance observed. This work provides novel insights into regulating bifunctional electrocatalytic activities in spin-polarized systems through a dual d-band center approach, utilizing nonmetal doping to optimize performance.

Zinc-bromine flow batteries (ZBFBs) are promising for sustainable energy storage due to their high energy density and cost-effectiveness. However, the sluggish kinetics of the Br2/Br- redox reaction at the cathode limits their performance. Here, we developed Fe/N co-doped micro-mesoporous carbon nanofibers (Fe-N-CNFs) as a high-performance cathode catalyst. Synthesized via electrospinning Fe/Zn-ZIFs with PAN/PVP, followed by carbonization, the Fe-N-CNFs exhibited a hierarchical pore structure with a specific surface area of 1057 m2 g- 1 and an average pore size of 2.5 nm. The optimized catalyst, doped with 4 wt% Fe, achieved an energy efficiency of 81 % at 80 mA cm- 2 and maintained a Coulombic efficiency of 98.4 % over 200 cycles. This work demonstrates the potential of integrating electrospinning with MOF-derived catalysts to enhance ZBFB performance, offering a scalable solution for high-efficiency energy storage systems.

The electrochemical nitrogen oxidation reaction (NOR) presents a sustainable pathway for nitrate synthesis under mild conditions; however, the process is hindered by the inadequate adsorption and activation of N2 on electrocatalysts. In this study, we utilized Co3O4 as a model catalyst and engineered lattice distortions by introducing oxygen vacancies, which expanded the eg band of the active sites to enhance N2 activation. The modified Co3O4 catalyst achieved a Faradaic efficiency of 10.68% and a nitrate yield of 58.80 μg·h-1·mgcat-1. Comprehensive experimental and density functional theory (DFT) analyses demonstrated that these modifications resulted in a shortened Co-N bond length and an elongated N≡N bond, leading to improved p-d hybridization between N2 and Co sites. Moreover, the enhancements in catalytic performance were also attributed to the improved electron transfer properties stemming from the altered band structure of Co3O4. This work provides innovative design principles for catalysts aimed at facilitating complex electrocatalytic reactions with multiple kinetics.

Electrochemical H 2 O 2 production through the two-electron oxygen reduction reaction (2e − ORR) represents a transformative route for sustainable and decentralized chemical synthesis. Nevertheless, conventional catalysts struggle to achieve optimal intermediates adsorption and efficient proton-coupled electron transfer (PCET) under neutral conditions, as the sluggish dissociation of water imposes a severe kinetic bottleneck. Herein, we introduce a lattice hydrogen engineering strategy that confers unprecedented catalytic functionality to traditionally inert metal oxides. Through precise hydrogen implantation into the TiO 2 lattice, we establish Ti-O 2C -H active centers—a dual-function motif that simultaneously achieves near-ideal OOH* adsorption (positioned at the Sabatier volcano apex) and intrinsic proton reservoir capability. This atomically engineered H-TiO 2 catalyst delivers > 95% H 2 O 2 selectivity, operating stably for over 100 h at an industrial current density of 200 mA cm −2 . This robust operation yields a high H 2 O 2 production rate of 13,968 mmol g −1 h −1 with an energy efficiency of 41.3%. Crucially, the universality of lattice hydrogen engineering is demonstrated through the activation of WO 3 , MoO 3 , and Nb 2 O 5 , yielding comparable performance enhancements for neutral 2e − ORR. By unlocking metal oxides as a robust catalyst platform for H 2 O 2 electrosynthesis, this work establishes a scalable pathway toward scalable, green and cost-effective peroxide production.

The electrical and thermal conductivity of binary Mg-1X (at%) alloys (X = Al, Ca, Sc, Mn, Zn, Y, Gd) were systematically investigated in temperature range of 300 K to 525 K in this work. The linear regression analysis is employed to establish the correlation between these two properties. The study found that there is a positive correlation between electrical conductivity and temperature, whereas there is a negative correlation between thermal conductivity and temperature for binary Mg alloys. The difference ratio of volume, difference of valence, and extra-nuclear electron configuration of solute element synergistically regulate both properties. According to the Smith-Palmer equation, the thermal conductivity of binary Mg alloys is linearly related to the product of electrical conductivity and temperature. Derived S-P equation is lambda= 1.838 x 10- 8T sigma+ 3.471, where Lorentz coefficient is 1.838 x 10- 8 V2 & sdot;k- 2 and phonon thermal conductivity is 3.471 W & sdot;m- 1 & sdot;K- 1.

Lithium-oxygen batteries (LOBs) face significant obstacles due to sluggish redox kinetics during oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) processes. The facile hydrothermally and vulcanization methods are applied to fabricate NiCo2S4 coated nitrogen-doped-carbon (NiCo2S4@NC) employing zeolitic imidazolate frameworks 67 (ZIF-67) templates. The distinctive and conductive dodecahedron architecture provides a high specific surface area and abundant porosity, exposing many active sites to improve electrolyte wetting and mass transport for efficient electrochemical reactions. Moreover, the redox activities of nickel and cobalt ions on the NiCo2S4 structure significantly enhance the catalytic efficiency towards ORR and OER. Additionally, the NC matrix improves electrical conductivity and structural reinforcement, effectively accommodating volume fluctuations during repeated cycling. As a result, the NiCo2S4@NC cathodes exhibit outstanding electrochemical properties, including high specific capacities, favorable rate capability, and extended longevity. This work presents in-depth insights into the electrochemical energy storage for LOBs by sufficiently utilizing synergistic effects from each unit of metal-organic framework (MOF)-derived polyhedrons.

Electrocatalysts with tuned valence states and compositions of metal atoms on their surfaces are considered to effectively tune the intrinsic electrocatalytic properties of the electrocatalysts. In this work, P doped hierarchical hollow Cu2MoS4 nanotubes (P-CMS) with rich Mo and Cu redox couples were fabricated and applied as the cathode catalysts for rechargeable lithium-oxygen batteries (LOBs). Material characterization results show that P atoms replaced part of S atoms and changed Cu and Mo valence states. As the P doping content increased, the proportion of low-valence Mo4+, activated high-valence Mo6+, and Cu2+ increased in CMS. Evidently, Mo4+ served as electron donator for oxygen reduction reaction (ORR), and Cu2+ facilitated the charge transfer and maintained catalyst structural stability. As ORR deepened, the amount of Mo6+ as electron acceptor for further oxygen evolution reaction (OER) increased. Such electrocatalysis-dependent redox couples of Mo4+/Mo5+/Mo6+ feature high catalytic activities and rapid valence-to-electron transfer, and Cu+/Cu2+ serve as conductor pairs and structural stability maintainer during electrochemical processes, in which high proportion of stable Cu2+ prevented Cu dissolution in electrolyte by surface reconstruction. Therefore, a rational methodology was developed for dynamic surface reconstruction of electrocatalyst during ORR and OER. This present work highlights that tailoring valence states of dual-metal sulfides propose an important strategy for surface reconstruction and stabilizing electrocatalytic activities.

Co3S4 electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction (OER) activity, yet challenges remain in fabricating rechargeable lithium-oxygen batteries (LOBs) due to their poor OER performance, resulting from poor electrical conductivity and overly strong intermediate adsorption. In this work, fancy double heterojunctions on 1T/2H-MoS2@Co3S4 (1T/2H-MCS) were constructed derived from the charge donation from Co to Mo ions, thus inducing the phase transformation of MoS2 from 2H to 1T. The unique features of these double heterojunctions endow the 1T/2H-MCS with complementary catalysis during charging and discharging processes. It is worth noting that 1T-MoS2@Co3S4 could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics, and 2H-MoS2@Co3S4 contributed to enabling moderate e(g) orbital occupancy when adsorbed with oxygen-containing intermediates. On the basis, the Li2O2 nucleation route was changed to solution and surface dual pathways, improving reversible deposition and decomposition kinetics. As a result, 1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co3S4 and MoS2 cathodes. This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.