Lithium-oxygen batteries are limited by the morphology of Li2O2 and its decomposition kinetics. Recently, in situ generation of oxides via electrolyte additives has been considered an effective strategy to regulate Li2O2 growth, while the relationship between such oxides and the electrode interface remains unclear. Here, La(NO3)3 is used as an electrolyte additive to generate electrochemically stable La2O3 in situ during discharge. On CNT, La2O3 and Li2O2 nucleate in a dispersed manner on the surface and grow independently, allowing Li2O2 to continuously grow into microsized particles. After introducing a small amount of nanosized Co3O4; however, the two species tend to undergo colocalized nucleation on the Co3O4 surface. Meanwhile, La2O3 imposes a confinement effect on Li2O2 growth, enabling nanosized Li2O2 to decompose at lower voltages and suppressing carbonate byproduct accumulation. As a result, the electrode exhibits lower polarization (reduced by 0.29 V) and more than twice the cycle life.

Understanding and controlling air-electrode structural evolution at elevated temperatures is crucial for efficient and durable protonic ceramic fuel cells (PCFCs). Here, a constricted potassium evaporation strategy is developed to induce ordered segregation in SrCo0.9Nb0.1O3−δ (SNC), transforming an otherwise inactive material into a highly active and stable cathode. The induced structural reconstruction generates uniformly distributed shell-core nanoparticles and an Sr/O-deficient perovskite phase, which greatly enhances oxygen reduction reaction (ORR) activity by promoting hydration kinetics and proton diffusion while suppressing detrimental SrO surface segregation. As a result, the reconstructed cathode delivers a peak power density of 744 mW cm⁻2 at 550°C, around 75% higher than that of pristine SNC, along with a low polarization resistance of 0.28 Ω cm2 and stable operation for over 500 h. Moreover, it functions as a robust bifunctional air electrode for reversible protonic ceramic electrolysis cells (PCECs) and oxygen-ion-conducting fuel cells, demonstrating broad applicability.

Understanding how atomic-scale surface structures govern catalytic pathways is central to advancing electrocatalysis yet remains poorly resolved in complex oxides. Here we develop an in situ titration platform integrating atomic layer-by-layer titration with reactivity quantification to dissect elevated-temperature oxygen incorporation reactions on (La0.5Sr0.5)FeO3-delta. We reveal a volcano-shaped correlation between oxygen incorporation reaction activity and SrO termination layers, and find that a single-layer SrO termination maximizes performance. Microkinetic modelling and theoretical calculations reveal a rate-determining step shift with surface termination. The single-layer SrO termination optimally balances oxygen dissociation, incorporation and subsurface diffusion by modulating charge transfer and steric constraints. This platform paves the way to quantitatively correlate catalytic activity with surface atomic structures, offering atomically precise surface engineering methodologies for designing high-performance electrocatalysts in energy and environmental applications.

Graphene has attracted considerable attention due to its exceptional thermal properties and potential applications in advanced thermal management systems. As the number of graphene layers increases, the cross-sectional area available for heat flow grows while the intrinsic in-plane thermal conductivity of each layer decreases because of enhanced interlayer scattering. The competing factors between the number of conducting channels and their interaction make understanding graphene's layer-dependent thermal conductivity essential for optimizing the thermal performance of graphene-based devices. In this study, the thermal conductivity of graphene with different layer numbers was measured by using a nanoscale thermal bridge method. Monolayer graphene exhibited a thermal conductivity up to 3100 W/m K, while the thermal conductivity further declined with layer number and stabilized beyond four layers. By evaluating the effective heat dissipation capability, a nonmonotonic dependence on graphene layer number was identified, with a critical regime appearing between 2 and 6 layers. The behavior was explained by a dual-path transport model, where both phononic and electronic heat carriers are considered. This layer-dependent reduction in thermal conductivity was attributed to phonon transport with an electronic heat-transport channel alongside. These findings provide insights into layer-dependent heat transfer in graphene and offer guidance for graphene-based thermal management and thermal design.

The practical reversibility of Li-O2 batteries is constrained by the electronically insulating discharge product Li2O2, which limits interfacial reaction kinetics, induces large charge polarization, and accelerates electrolyte decomposition. Here we introduce Pr(NO3)3 as an electrolyte additive to generate in situ an amorphous, three-dimensional PrOx framework on a Co3O4/CNT cathode during the first discharge. This framework confines Li2O2 growth to produce nanosized, poorly ordered Li2O2 and, at the same time, provides abundant active sites and continuous electron pathways for O2 redox and Li2O2 formation/decomposition. As a result, the voltage gap decreases from 1.66 to 1.16 V at 200 μA cm-2 under a limited capacity of 400 μAh cm-2. The lowered charging potential also suppresses Li2CO3 formation, leading to an improved cycling stability.

Hydrogen incorporation into metal oxides enhances their electrochemical properties, making them highly suitable for various energy conversion applications. The controlled distribution of hydrogen ions in material systems and their conduction at elevated temperatures have garnered significant attention for various energy storage and environmental monitoring applications, including fuel cells, smart windows, and sensor technologies. In this work, cost-effective, high-concentration hydrogen-doped SrFeO3-δ (HSrFeO3-δ) films were prepared under ambient conditions by treating Al(s)|SrFeO3-δ(s) films with KOH(aq), utilizing electron-proton codoping to investigate hydrogen distribution. The uphill hydrogen distributions in SrFeO3-δ films with compressive strain, in contrast to the density gradient behavior under tensile strain, suggest the fundamental role of the strain states in the hydrogen accommodation. Compressively strained films with a rich Al source follow an anomalous uphill feature of hydrogen distribution, highlighting their potential use as electrolyte for fuel cells. The strain significantly influences the structure, chemical lattice coupling, and consequently the ionic transport in SrFeO3-δ. Ionic conductivity measurements reveal that compressively strained HSrFeO3-δ films with uphill hydrogen distributions exhibit a significant ionic conductivity of 0.189 S/cm at 413 K, with an activation energy of approximately 0.29 eV, making them suitable for low-temperature electrochemical applications. These findings provide a promising approach for tuning material properties and valuable insights for building iontronic devices.

Electrochemical reduction of nitrate to ammonia is challenged by the high dissociation energy of nitrate, sluggish kinetics and competitive aide reactions. This study proposes PdNi alloy nanocryatals, formed by P & aring; deposition mediated in situ generation of Ni metallic species over defective Lap 52 Cao 20 No.06 Tio. 940s perovskite nanofibers, as a catalyst for nitrate reduction reaction. Such catalyst delivers an NHs yield rate of 21.13 mgh 'mgal (about 4226 mgh 'mga) and a maximum Faradaic efficiency of 98.78 % at 1.0 V. Theoretical studies reveal that the adjoining of PdNi nanocrystala and oxygen vacancies on perovskite facilitate the nitrate hydrogenation and reduce dissociation energy of nitrates by enhancing the adsorption of reaction intermediates and suppresses the hydrogen evolution reaction. This technique provides provide a way for developing advanced catalysts with metallic phases and oxygen vacancies for optimised electrochemical nitrate itrate reduction.

The ever-increasing emissions of volatile organic compounds (VOCs) from industrial activities pose significant environmental and health risks. Nonthermal plasma (NTP) degradation technology has emerged as a prominent method for VOC degradation due to the mild reaction conditions but demands an efficient catalyst for high product conversion. This study presents a mesoporous layered NiFe double silicate catalyst fabricated by the reaction between 13X zeolite and layered double hydroxides (LDHs). Under NTP conditions, the catalysts achieved a 90% ethyl acetate conversion with a CO2 selectivity of 45%, maintaining stability over 400 min. The performance demonstrates synergy in adsorption and offers more active catalytic sites on the in situ-generated layered NiFe double silicate over zeolite catalyst. Simulation results also suggested that the two-dimensional sheet structure effectively localizes the electric field on the zeolite surface and therefore may facilitate the generation of active species with plasma and ethyl acetate adsorption. This work provides a pathway for the design of highly efficient and stable catalysts for NTP applications.

Protonic ceramic electrochemical cells (PCECs) can operate at intermediate temperatures (450° to 600°C) for power generation and hydrogen production. However, the operating temperature is still too high to revolutionize ceramic electrochemical cell technology. Lowering the operating temperature to <450°C will enable a wider material choice and reduce system costs. We present approaches to redesigning PCECs via readily fabricated single-grain–thick, chemically homogeneous, and robust electrolytes and a nano-micro positive electrode. At 450°C, the PCECs achieve a peak power density of 1.6 watt per square centimeter on H 2 fuel, 0.5 watt per square centimeter on NH 3 fuel, and 0.3 watt per square centimeter on CH 4 fuel in fuel cell mode. In steam electrolysis mode, a current density of >0.6 ampere per square centimeter with a Faradaic efficiency of >90% is achievable at 1.4 volt and 400°C. In addition, exceptional durability (>2000 hours) has been demonstrated, with a degradation rate of <0.01 millivolt per 100 hours in fuel cell mode at 400°C.

High-capacity Co-free Ni-rich layered oxides are promising cathode materials for lithium-based batteries, but they suffer from chemo-electro-mechanical instabilities. While single-crystal morphologies reduce these issues, slipping, and microcracking persist during extended cycling, and the degradation mechanisms remain inadequately understood. Herein, we report on multi-directional planar slipping and microcracking along the (003) and (100) planes in a single-crystal LiNi0.75Mn0.25O2 (LNM) cathode. According to the Darken-Gurry theory and formation energy in LNM, magnesium (Mg2+) has been selected as the best pillaring element to strengthen the structural integrity and improve cycling stability. Notably, Li0.99Mg0.01Ni0.75Mn0.25O2 (LMNM) achieves a capacity retention of 91% after 1000 cycles at 4.3 V operation against graphite by alleviating instability issues. We systematically unravel the pillaring effect, for the first time, from the quantum scale to the lattice level and from the microscale to the macroscopic level of the cathode particles, providing an in-depth understanding of chemo-electro-mechanical degradation.

The electrooxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a monomer for degradable bioplastic, is a promising strategy for biomass upgrade and yet requires well-designed catalysts with high efficiency and selectivity. Taking advantage of the open metal sites of metal-organic frameworks (MOFs), quasi-MOFs represent viable catalysts, but the poor designability and unpredictable structures hinder their development. In this work, a Ni-based quasi-MOF was rationally designed and synthesized by controlled ligand engineering. Compared to the fully occupied metal clusters in the pristine MOFs, the accessible Ni sites in quasi-MOFs can efficiently convert HMF to FDCA with remarkable Faradaic efficiency (99.2%) and FDCA selectivity (98.3%). In situ characterizations and mechanistic analysis revealed that the open Ni sites created by partial ligand disconnection in quasi-MOFs are critical to the formation of high-valent active species and HMF oxidation. Moreover, serving as the anode in an integrated electrolysis system, such a quasi-MOF can not only reduce the cell voltage for hydrogen generation but also produce high-purity FDCA with good yield, offering a new opportunity for the simultaneous production of high value-added chemicals and sustainable hydrogen.

Transition metal perovskite oxides are employed as air electrode catalysts for solid-oxide fuel cells and electrolyzers. However, degradation linked to cation segregation and precipitation involving alkaline-earth substituents limits their commercialization. In this work, we engineered a multilayer electrode consisting of an ultrathin (La1_xSrx)FeO3_s catalyst overlayer (x = 0, 0.5), a cation-migration-suppression Pr0.1Ce0.9O2_ s layer, and a bulk-transport (La0.5Sr0.5)FeO3_ s layer. This "trilayer" electrode structure enables the surface reactivity and stability to be optimized independently from the bulk transport: an architecture that mitigates the segregation of available Sr and other cations from the bulk reservoir and their subsequent precipitation at the solid-gas interface. This trilayer architecture reduced surface reaction resistance and long-term degradation by over an order of magnitude at 650 degrees C over 48 h. The approach offers a general pathway for designing multilayer electrode coatings with decoupled catalytic and transport functionalities.

Conventional polycrystalline LiMn2O4 (PC-LMO) suffers from poor Li+ diffusion rates and structural instability, negatively affecting its electrochemical performance. Here, we design a single-crystal LMO cathode material using BaO flux (SC-LMOB) to address these issues. The BaO flux enables the fabrication of brick-like single-crystal particles, enhancing Li+ diffusion by shortening the diffusion path and increasing the unit cell volume. This process also reduces the specific surface area and stabilizes the crystal structure, effectively mitigating Mn dissolution and polarization. As a result, SC-LMOB exhibits ultra-high rate performance and superior structural stability, retaining 88.8% of its capacity at a 20 C discharge rate and achieving capacity retentions of 85.3% and 86.0% after 500 and 300 cycles at 1 C at room and elevated temperatures, respectively. This structural design offers a low-cost, scalable approach for fabricating single-crystal cathode materials with excellent performance.

Transition metal oxides are promising candidates in the field of thermoelectricity, which can convert heat and electricity into each other and realize the efficient utilization of waste energy. For the figure of merit ZT = S2σT/(κe + κl), a lower thermal conductivity is desired for an enhanced ZT, and cation doping is an appropriate way to regulate the thermal transport properties. However, because S, σ, and κe are strongly coupled with each other, cation doping for one parameter modification can generate compensation with others, making regulation more difficult. In this work, we demonstrate the effective engineering of the thermal conductivity of SrTiO3 films by partial oxygen isotope substitution with 18O using a straightforward aftergrowth thermal annealing process. The results show that the isotope disorder promotes the scattering of phonons and generates a nearly 20% decreased thermal conductivity of SrTiO3 films. Our work provides a convenient new route for the design of thermoelectric materials with high ZT values.

Reducible rare earth oxides (REO2-x) are essential in catalysis due to their 4f band-governed surface redox properties, which influence crucial reactions such as hydrogen dissociation and water formation. However, correlating the 4f band structure with catalytic activity has been a long-standing challenge due to the complexities of manipulating and characterizing 4f electrons. Here, we demonstrate that tensile strain effectively modulates the 4f electronic structure, narrowing the band gap and activating surface oxygen, leading to enhanced redox activity. Using atomically flat ceria ultrathin films under up to a 7% biaxial strain range, we observed a five-fold increase in surface reaction kinetics via time-resolved ambient-pressure X-ray photoelectron spectroscopy. Complementary density functional theory calculations reveal that the tensile strain reduces energy barriers for key catalytic steps by narrowing the 4f-2p band gap. These findings highlight the RE 4f electronic structure as a critical descriptor for catalysis and demonstrate the utility of atomically flat model systems.

The unique structural features of high entropy oxides (HEOs) offer opportunities for flexible and precise structure control, thereby fostering a broad spectrum of structure–property tuning. This review surveys the extensive research carried out on HEOs, from initial exploration to recent advancement, summarizing progress in the refinement of synthesis techniques, elucidation of the high entropy effect, and understanding of atomic structures at multiple scales. Leveraging the impact of high entropy effect on structures, HEOs exhibit a wide range of properties from thermal to electrical, which have potential applications in fields such as thermoelectrics, dielectrics, energy storage, lithium batteries, catalysis, magnetism and supercapacitors. The correlations between structure and property are analyzed, and potential property-property relations are examined. Finally, we underscore the key challenges and unresolved questions that future research needs to address.