P2-type layered transition metal oxides (TMOs) are among the most promising cathode materials for sodium-ion batteries due to their high capacity and energy density. However, their practical application is hindered by irreversible phase transitions and lattice oxygen loss at high voltages, while Mn3+-induced Jahn-Teller distortion and P2-P ' 2 phase transitions at low voltages accelerate structural degradation and capacity fading. Here, we present a Mg/Cu co-doping strategy to systematically regulate structural evolution and redox chemistry, addressing these key degradation mechanisms. Mg2+, with strong electrostatic interactions and a small ionic radius, acts as an "anchoring" agent during deep sodiation (low potential), stabilizing the transition-metal layers, suppressing Mn disproportionation and Jahn-Teller distortion, and mitigating the P2-P ' 2 phase transition. Cu2+, in contrast, functions during deep desodiation (high potential) by enhancing Ni-O bond ionicity and lowering the charge-transfer barrier between O 2p and transition-metal 3d orbitals, thereby reducing lattice oxygen participation, transition-metal dissolution, and interlayer gliding, and delaying the P2-O2 phase transition. Benefiting from this synergistic effect, Na0.67Ni0.2Mn0.65Mg0.1Cu0.05O2 exhibits excellent electrochemical performance, retaining 80% of its capacity after 300 cycles at 1C in the 2.0-4.5 V window and maintaining a high reversible capacity of 78.5 mAh g-1 at 20C. This work not only provides a solution to the dual high-/low-voltage degradation challenge in P2-type TMOs but also elucidates the underlying mechanism of multi-element co-doping, offering a strategy for designing high-energy-density, long-life sodium-ion battery cathodes.

High-rate impact loading causes structural failure and insufficient energy dissipation in protective materials. The intrinsic stiffness-damping trade-off in polymer materials makes it highly challenging to simultaneously achieve strong damping and broad frequency energy dissipation. Here, we developed tough ionogels with enhanced shear-stiffening and damping capabilities through the synergy of dynamic bonds and steric hindrance of hyperbranched polymeric ionic liquids (HPILs). The synergistic coupling of dynamic-bond dissociation in the high-frequency regime and the topological constraint of viscous-flow HPILs in the low-frequency regime endows the ionogels with broad-frequency damping and pronounced shear-stiffening behavior. The prepared ionogel shows an 842-fold shear-stiffening response and high damping (tan δ > 1) across a wide frequency range (10- 3-105 rad s- 1). At a high impact rate of 4000 s- 1, it also exhibits high impact strength (248.6 MPa) and toughness (86.5 MJ m- 3). This strategy provides a reference for the design of next-generation high-performance damping ionogels.

Achieving simultaneous enhancement of Na+ storage capacity, rate capability, and cycling stability remains a major challenge for biomass-derived hard carbon anodes because the defect-rich structure that provides abundant storage sites often sacrifices interfacial stability and charge-transfer kinetics. Herein, a nitrogen-doped soft carbon shell was in situ engineered on bamboo-derived hard carbon via a chemical vapor deposition (CVD) process using polyvinylpyrrolidone (PVP) as both the carbon and nitrogen source. The introduced nitrogen dopants expand the interlayer spacing and enhance electronic conductivity, while the soft carbon shell stabilizes the electrode/electrolyte interface and facilitates electron/ion transport. Benefiting from this synergistic structural design, the modified hard carbon delivers a reversible capacity of 503.18 mAh g-1 at 0.03 A g-1. Under a high current density of 0.3 A g-1, a reversible capacity of 376.3 mAh g-1 is maintained, with a capacity retention of 94.57% after 300 cycles. Detailed structural and electrochemical analyses reveal that the enhanced performance arises from expanded interlayer spacing, accelerated charge kinetics, and a stabilized electrode/electrolyte interface. This work demonstrates a rational strategy for regulating the defect chemistry and interfacial architecture of biomass-derived carbon anodes.

Hydrogen’s high energy density and zero carbon nature make it a key fuel for carbon neutrality, yet its flammability demands room temperature (RT) H2 sensors with low detection limits. Here, we report a humidity-insensitive RT hydrogen sensor based on Pd nanoparticle decorated monolayer MoS2 (Pd MoS2), which exhibits excellent stability and selectivity. The Pd loading was systematically tuned to maximize the sensing performance at RT (~25 °C). The resulting sensor delivers a reliable performance across a wide detection range (25 - 20,000 ppm), with fast response/recovery times (31.5/43.5 s), robust humidity tolerance (up to 75% RH), and outstanding long-term stability exceeding 20 weeks. Moreover, the sensing performance (e.g., sensitivity and selectivity) is further enhanced by coating a poly(methyl methacrylate) (PMMA) molecular sieve layer onto the sensor surface. Notably, the PMMA layer not only blocks interfering gases via size sieving but also boosts H2 sensitivity, improving the "S" _("H" _"2" )/SCO from 635% to 1170%. This work highlights that combining noble metal decoration with a molecular sieve protective layer offers a viable strategy to simultaneously achieve high selectivity, enhanced sensitivity, and good stability for RT 2D material based H2 sensors.

Sn-based compounds are attractive candidates for lithium-ion batteries (LIBs) owing to their high theoretical capacity. However, their widespread application is severely hindered by pronounced volume fluctuations and poor electrical conductivity. While heterostructure engineering has been employed to address these issues, conventional static heterojunctions often degrade during cycling, especially in conversion-type systems, limiting their long-term effectiveness. Herein, we propose a dynamic heterojunction engineering strategy through the construction of a SnS/V2O5@C (SSV@C) composite structure to achieve the synergistic integration of conversion and intercalation-type lithium storage mechanisms alongside in situ interfacial reconstruction during electrochemical cycling. During the conversion and alloying reactions of SnS, the initial SnS/V2O5 heterointerface gradually evolves into a Sn/V2O5 heterostructure, continuously generating active interfaces that establish a stable built-in electric field, thereby facilitating charge separation and rapid charge transport. Meanwhile, the layered structure of V2O5 effectively buffers volume expansion, thereby alleviating mechanical stress and enhancing overall structural stability and electrochemical reversibility. Consequently, the SSV@C anode material delivers a high reversible capacity of 909.5 mAh g−1 at 0.1 A g−1 and an exceptional cycling lifespan with a capacity of 230.1 mAh g−1 after 8000 cycles at 20 A g−1. This work provides a mechanistic foundation and design blueprint for advanced heterostructured anodes in high-performance energy storage systems.

Lithium metal, with its ultrahigh theoretical capacity and lowest electrochemical potential, is considered one of the most promising anodes for next-generation rechargeable batteries. However, its practical application remains severely limited by the instability of the electrode-electrolyte interface. This Perspective critically evaluates the limitations of current interfacial engineering strategies and argues that optimizations focused solely on individual materials or single-scale structures are insufficient to address the coupled electrochemical, mechanical, and chemical degradation processes governing lithium metal failure. Key bottlenecks-including the fragile and system-dependent solid electrolyte interphase (SEI), uncontrolled dendrite growth, continuous parasitic reactions, and poor solid-solid interfacial contact-are systematically analyzed. Based on these challenges, we propose a unified conceptual framework in which future research directions are directly linked to specific failure mechanisms. These include advanced characterization combined with mechanistic understanding to reveal dynamic interfacial evolution and failure pathways, multiscale coupled design to establish cross-scale synergistic regulation principles, and dynamic adaptive interfacial regulation to stabilize interfacial structures and optimize electrochemical functionality. We further emphasize that manufacturing-compatible engineering strategies capable of bridging laboratory-scale innovations with practical industrial implementation will be essential for the successful commercialization of lithium metal batteries.

O3-type NaNi1/3Fe1/3Mn1/3O2 (NFM) is a promising sodium-ion battery cathode due to its low cost and high theoretical capacity, but its structural instability, Fe migration, and Jahn-Teller distortion lead to severe phase transitions and capacity decay. Here, we report a dopant-free radial composition and Na-deficiency co-regulation strategy, which constructs a non-typical O-phase by controlling the radial Fe gradient and Na vacancy concentration, simultaneously optimizing the electronic structure and Na+ transport kinetics. X-ray diffraction (XRD) and ex situ X-ray absorption spectroscopy (XAS) reveal that Na0.95Ni0.33Fe0.28Mn0.39O2 possesses wider interlayer spacing and a more robust Ni/Mn-O framework. Density functional theory (DFT) calculations show that Fe migration induces self-adaptive modulation of the transition metal layers, strengthening Ni/Mn-O bonds and downshifting the O 2p band, suppressing lattice oxygen oxidation and achieving Ni oxidation protection and structural stabilization. The material delivers 76.3% capacity retention after 200 cycles at 1 C (2.0-4.0 V), demonstrating excellent cycling and rate performance. In situ XRD and other electrochemical analysis methods indicate enhanced Na+ diffusion, reduced charge-transfer resistance, and highly reversible structural evolution, effectively suppressing irreversible phase transitions and microcracks. This study demonstrates that tuning elemental distribution and Na stoichiometry can synergistically improve Na+ transport kinetics and structural stability, providing a novel strategy for designing high-performance sodium-ion battery cathodes.

Thermal runaway (TR) in lithium-ion batteries (LIBs) remains an intrinsic safety issue, posing significant risks of fire and explosion. Among various technologies employed to assess LIB status- including temperature, pressure, voltage, and gas measurements-gas sensors exhibit superior response speed and stronger sensing abilities. Notably, H2 has been identified as the first gas released during the TR process when compared to other gases such as CO2, CO and CH4. Furthermore, H2 serves as an indicator for the formation of trace Li dendrites, which are inducements of LIBs safety issues. Consequently, development of high performance H2 sensors is essential for providing timely early safety warning. Compared with other types of H2 sensors, chemiresistive H2 sensors have garnered significant attention owing to their good sensitivity, low cost, and easy of miniaturization and integration into LIB cells. This review presents a comprehensive overview of chemiresistive H2 sensors through classifying them into different categories based on sensing material systems. Within each category, the inherent fundamental sensing mechanisms and current strategies aimed at enhancing sensor performance have been systematically discussed. It is believed that chemiresistive H2 sensors would play an important role in TR monitoring. Moreover, a more accuracy prediction could be implemented when H2 sensors are integrated with other existing warning methods.

Atomically precise metal nanoclusters (NCs) offer distinct platforms for exquisite control over photophysics, yet their complex photoluminescence (PL) mechanisms remain elusive. Here, we investigate a correlated series of Au24(SR)20 with the same core but different R groups, revealing a unified triple-emission mechanism modulated by the R groups. By integrating cryogenic PL, femtosecond transient absorption and time-resolved electron paramagnetic resonance, we provide the first direct experimental "fingerprint" of short-lived excited triplet state (T1) of ∼350-nanosecond lifetime at room temperature, resolving the exciton relaxation cascade from the initial singlet state (S1) to a distorted singlet state with charge-transfer character to a T1. These states contribute to multiemission (600 to 1400 nanometers, visible to near-infrared). Crucially, the R group symmetry of the 3,5-dimethylbenzylthiolate ligand-induced locking increases the kinetic barrier for structural distortion. This rigidity inhibits S1 rotational relaxation and decelerates intersystem crossing, yielding enhanced solution fluorescence. This study proposes a paradigm for designing efficient, multiemissive NCs by manipulating the excited-state dynamics and spin character.

In ultrahigh-nickel layered cathode materials, regulating the morphology and arrangement of primary particles is a strategy that effectively to mitigate particle microcrack formation and enhance structural stability during electrochemical cycling. Nevertheless, current investigations on Ta-doped cathodes have primarily focused on the relationships between primary particle morphology, size distribution, and electrochemical performance. The fundamental mechanisms by which Ta doping influences primary-particle evolution, lattice microstrain, stress redistribution during electrochemical cycling, mechanical strength, and structural stability remain poorly understood. In this work, a Ta doping strategy was employed to engineer the microstructure of LiNi0.90Co0.05Mn0.05O2 cathodes, resulting in refined and radially aligned primary particles. The results reveal that LiNi0.90Co0.05Mn0.05O2 containing 0.5 mol% Ta exhibits refined radially aligned primary particles, reduced lattice microstrain, possessed more homogeneous stress distribution, and diminished strain fluctuations during cycling, which collectively contribute to enhanced mechanical strength and improved cycling stability. This work establishes the correlations among microstructural characteristics, chemo-mechanical behavior, and electrochemical performance laying the foundation for the rational design of high-stability Ni-rich layered cathodes.

With the continuous rapid growth in the volume of spent lithium-ion batteries, developing an environmentally friendly, cost-effective, and efficient recycling process for cathode materials has become a key scientific challenge for the sustainable development of the new energy industry. Conventional hydrometallurgical recycling technologies typically rely on strong acids combined with external reducing or oxidizing agents, which lead to high reagent consumption and operating costs while generating large volumes of metal-containing wastewater, posing significant environmental and disposal challenges. Therefore, it is of great scientific and practical significance to develop a novel recycling process that eliminates the need for external chemical additives while enabling the synergistic recovery of multiple components. In this study, an additive-free recycling strategy based on an intrinsic synergistic redox mechanism is proposed for a mixed system of spent LiFePO4 (S-LFP) and LiMn2O4 (S-LMO). This approach fully utilizes the electrochemical potential difference between different electrode materials to drive spontaneous electron transfer reactions under mildly acidic conditions, with acid consumption reduced by nearly half compared to conventional methods. Specifically, Fe2+ ions are first leached from S-LFP and act as intrinsic reducing agents in the solution; these Fe2+ ions subsequently reduce Mn3+ to Mn2+ in S-LMO, thereby promoting the efficient co-leaching of Mn and Li. This process achieves the synergistic recycling of the spent materials, reaching nearly 100% leaching efficiency for Mn and Li under mild conditions (20 ℃, 40 min), demonstrating excellent reaction kinetics and synergistic effects. Concurrently, Fe species are selectively converted into insoluble FePO4 precipitates, allowing for easy solid-liquid separation. The resulting FePO4 can directly serve as a precursor for the regeneration of LiFePO4 (R-LFP). The leachate is further processed by adjusting the pH with ammonia to precipitate Mn(OH)2, followed by the addition of Na2CO3 to obtain Li2CO3, thereby achieving the full recovery and reuse of Fe, Mn, Li, and P elements. The regenerated R-LFP exhibits a uniform spherical morphology with a narrow particle size distribution and a well-preserved crystal structure. Electrochemical testing reveals that the regenerated material delivers an excellent discharge capacity of 135.0 mA·h/g and a capacity retention of 99.4% after 200 charge-discharge cycles, indicating outstanding cycling stability and structural reversibility. This work systematically elucidates the self-driven redox mechanism between spent electrode materials and achieves closed-loop recovery of all constituent elements along with the regeneration of high-value-added materials. The entire process relies solely on spontaneous electron transfer between the waste materials, without the need for external oxidizing or reducing agents, significantly lowering energy consumption, reagent usage, and secondary pollution. The proposed synergistic redox strategy overcomes the limitations of conventional hydrometallurgical processes and provides a new theoretical foundation and practical pathway for the green, efficient, and sustainable recycling of multi-component spent lithium-ion batteries, showing great potential for large-scale industrial application.

Ta2NiSe5 is a room-temperature excitonic insulator (EI) with strong electron-phonon coupling. However, the evolution of this coupling across the phase transition remains elusive. Here we investigated the nonequilibrium dynamics of Ta2NiSe5 under pressure using time-resolved reflectance spectroscopy (TRS). Below 1 GPa, the 2 THz order-parameter-coupled coherent phonon (OPCCP) exhibits an extended coherence lifetime, which indicates the protection of the exciton condensate and is consistent with the rapid recovery of the EI phase. In contrast, the onset of the OPCCP is delayed at higher pressures due to inefficient energy transfer mediated by preformed excitons. Furthermore, the presence of quasi-elastic scattering in Raman spectra and the enhancement of the 2 THz mode asymmetry factor 1/|q| suggest that the system enters a preformed exciton-dominated regime at higher pressures. This study reveals the regulatory effects of different exciton states on coherent phonons.

Mixed-anion semiconductors exhibit ultralow lattice thermal conductivity, yet conventional Boltzmann transport, including only three-phonon scattering, cannot capture their strong anharmonicity. Here, first-principles simulations incorporating four-phonon interactions and coherent phonon transport reveal strain-driven thermoelectric enhancement in CuBiSeCl2. Four-phonon scattering strengthens mode coupling and slightly enhances phonon coherence, while tensile strain suppresses it through vibrational mode decoupling, reducing the coherent contribution by 17% and yielding κL = 0.33 W m-1 K-1 at 300 K. Tensile strain notably enhances quartic anharmonicity and weakens Cu-Cl bonding. Simultaneously, it narrows the band gap to 1.22 eV and lowers the electron effective mass along the b axis to 0.211 m0, improving the power factor to 0.29 mW m-1 K-2 at 700 K. The combined thermal and electronic optimization produces a peak ZT ≈ 0.8 at 800 K for n-type doping, highlighting that four-phonon scattering, phonon coherence, and strain engineering jointly govern heat and charge transport in strongly anharmonic thermoelectric materials.

High thermoelectric efficiency has been reported in several antiperovskites, but strongly unbalanced n- and p-type thermoelectric performances still limit practical device integration. Here, we show that Ag3SX (X = Cl, Br, I) antiperovskites exhibit simultaneously favorable p- and n-type transport, and that halogen substitution further improves this ambipolar behavior through coupled lattice and electronic mechanisms. On the lattice side, heavier halogens soften the Ag-X framework and strengthen anharmonic phonon scattering, which markedly lowers the lattice thermal conductivity and helps drive the materials toward a glasslike transport regime. On the electronic side, halogen substitution modifies the relative contributions and hybridization of Ag-4d and chalcogen/halogen p states near the valence-band edge; together with the stronger spin-orbit coupling in the iodide, this leads to enhanced valence-band degeneracy while retaining sufficient band dispersion. As a result, Ag3SI exhibits ultralow lattice thermal conductivity (0.29 W/m K) and high carrier mobility (10-200 cm2/V s), achieving a maximum power factor of 2.5 mW/m K2. Under optimal doping, ZT at 800 K reaches approximate to 2.42 for p-type and approximate to 1.87 for n-type carriers. These results identify Ag3SX compounds as promising ambipolar thermoelectric materials and highlight how lattice anharmonicity and band-edge reconstruction can be combined to optimize heat and charge transport.

While 2D high-kappa dielectrics are promising for extending Moore's Law, their adoption is hindered by limited crystallinity, low dielectric constant, and high-temperature processing incompatible with back-end-of-line integration. To overcome these challenges, we developed a low-temperature (170 degrees C) chemical vapor deposition technique to grow single-crystalline 2D bismuth oxychloride (BiOCl), achieving large-area flakes with an average edge length of 31.5 & micro;m. The resulting BiOCl-based metal-insulator-metal devices exhibit a high dielectric constant of 16.9 and a high breakdown field of 11.2 MV cm-1. When integrated as the gate dielectric in a back-gated MoS2 field-effect transistor, BiOCl enables outstanding electrical performance: an on/off current ratio of 108, a near-ideal subthreshold swing of 61 mV dec-1, a low normalized hysteresis of 1.39 & times; 10-2 V (MV cm-1)-1 at 0.04 V s-1, a field-effect mobility of 17.9 cm2 V-1 s-1, and a low interface trap density of 5.82 & times; 1010 cm-2 eV-1. The devices also show robust stability, with no degradation in the on/off ratio and only a slight threshold voltage shift after 3 months. This work establishes 2D BiOCl as a leading high-kappa dielectric candidate, offering a practical route to overcoming scaling limits and enabling next-generation low-power nanoelectronics.

Hydrogen (H2) safety monitoring demands sensors that operate reliably across the entire trace-to-percent-level concentration range, a persistent challenge for conventional metal-oxide systems. Herein, a temperature-gated sensing strategy is demonstrated using PdO/Pd-decorated, metal-organic framework (MOF)-derived ZnO nanorod arrays. Conformal coating of vertically aligned ZnO nanorods with a conductive Zn-catecholate (Zn-CAT) MOF, followed by thermal conversion, yields highly porous ZnO@ZnO homojunctions functionalized with PdO/Pd nanoparticles. This optimized hierarchical architecture enables a single chemiresistive device to operate in two distinct regimes. At 125 °C, it achieves trace H₂ detection (0.02-50 ppm) with a theoretical limit of 49 ppb. At 250 °C, it delivers an ultrahigh response (3632 to 1% H2) while maintaining near-linear behavior up to 2.5%. Crucially, operando near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) explicitly unravels the underlying mechanism, revealing a transition from low-temperature oxygen-mediated pathways to high-temperature PdHx-assisted dissociative spillover. This continuous detection window, spanning approximately 5 orders of magnitude, bridges the gap between early-warning and catastrophic-release monitoring for full-scenario H2 safety.

The sustainable upcycling of delithiated FePO4 and MnO2 residues from spent lithium-ion batteries (LIBs) is challenged by fluoride cross-contamination, crystalline incompatibility, and low economic value. Herein, a direct mechanochemical regeneration strategy is proposed to convert FePO4 and MnO2 into high-performance F-doped LiMn0.4Fe0.6PO4, featuring the structurally inherited robust olivine framework of FePO4, defect-enabled homogeneous Mn incorporation from MnO2, and stabilized Mn/Fe-O bonding network through F-doping. As a result, the optimized material delivers a high capacity of 136.76 mAh g-1 at 1 C with 89.74% retention after 600 cycles and 118.74 mAh g-1 at 10 C. Mechanistic analyses reveal that defect-mediated Mn/Fe intermixing and F-doping synergistically suppress Jahn-Teller distortion, enhance structural stability, and improve Li+ diffusion. Technoeconomic and environmental assessments suggest the well-round efficiency of the upcycling route with elucidated structural evolution of LiMnxFe1-xPO4 (LMFP) and functional modification of the F element, thereby establishing a practical candidate toward sustainable upcycling of spent LIBs.

Nickel-rich layered oxides are considered highly promising cathode materials for all-solid-state batteries (ASSBs) due to their high theoretical specific capacity and energy density. In this study, a comparison between polycrystalline and single-crystalline cathode materials was conducted. It was found that, during the charging process, ion transport at the interface of polycrystalline cathodes is significantly influenced by phase transitions and side reactions with the electrolyte, resulting in an irreversible increase in impedance after cycling. Furthermore, the structural stability of the cathode material affects internal ion diffusion kinetics, thereby influencing its electrochemical performance. Unlike single-crystalline materials, ion migration in polycrystalline materials must traverse anisotropic grain boundaries, which, due to anisotropic lattice contraction, evolve into intergranular cracks, leading to reduced ion diffusion kinetics and degraded electrochemical performance. In contrast, single-crystalline cathodes exhibit more stable interfacial resistance and uniform ion transport during charging, ensuring structural stability over long-term cycling. Consequently, at a 0.5 C rate, the single-crystalline cathode maintains a specific capacity of 143 mAh/g after 500 cycles, with a capacity retention of 89.2%, while preserving its intact single-crystal morphology. This study provides valuable new insights into the localized lithium-ion transport behavior in single-crystalline and polycrystalline cathode materials for sulfide-based all-solid-state batteries.

Electrochemical CO2 reduction (eCO2RR) provides a promising route for converting CO2 into value-added carbon monoxide (CO), a key feedstock for chemical synthesis. Silver-based catalysts are among the most effective materials for this process; however, their practical development is often hindered by the poorly defined nature of their active sites, which limits precise structure-activity correlations. Herein, we report the synthesis of a structurally well-defined Ag+/Ti4+ bimetallic titanium-oxo cluster, Ti6Ag6, stabilized by thiacalix[4]arene ligands. The cluster adopts a distinctive linear architecture comprising three types of surface-exposed Ag sites. When applied to eCO2RR, Ti6Ag6 exhibits outstanding catalytic performance, delivering over 90% faradaic efficiency for CO across a wide potential window. DFT calculations reveal that the central bridging Ag site exhibits the highest intrinsic activity, attributed to its superior ability to stabilize the *COOH intermediate.