Li-rich layered oxide cathodes enable ultrahigh energy density through oxygen redox chemistry but suffer from severe structural degradation and thermal instability caused by irreversible oxygen loss and transition-metal migration. Here, a bond-level regulation strategy is proposed by introducing lithium manganese iron phosphate as a surface buffer layer to induce a bond crosstalk between P-O and transition-metal-O bonds. This crosstalk effectively suppresses oxygen release, restrains transition-metal migration, and stabilizes the layered framework during cycling. As a result, the modified cathode delivers outstanding voltage retention of 87.35% after 500 cycles with an ultralow voltage decay. Moreover, the P-O and TM-O bonds interaction markedly enhances thermal robustness, leading to delayed thermal runaway and excellent high-temperature cycling stability (81.7% capacity retention after 200 cycles at 50 degrees C). This work establishes bond crosstalk engineering as an effective strategy for simultaneously improving the durability and safety of Li-rich cathodes.

Li-rich Mn-based oxides (LRMOs) are highly attractive cathodes for next-generation lithium-ion batteries due to their substantial capacity enabled by anionic redox reactions (ARR). However, balancing ARR activity with structural stability remains a major bottleneck. Here, we identify oxygen partial pressure during synthesis as a decisive factor governing this balance. Using single-crystal Li1.2Ni0.13Co0.13Mn0.54O2, we systematically regulate the calcination atmosphere-argon (LRMO-0), air (LRMO-20), and oxygen (LRMO-100)-to tune oxygen-vacancy levels, transition-metal valence states, and cation disorder. Low oxygen partial pressure results in excessive oxygen vacancies and suppressed reversible ARR, leading to poor capacity and rate performance. Conversely, high oxygen partial pressure over-activates ARR, triggering irreversible oxygen release and structural degradation. Notably, LRMO-20 synthesized in air achieves the optimal compromise, delivering a 259 mAh g(-1) initial discharge capacity, 90.1% retention after 500 cycles, and markedly reduced phase transformation. This work clarifies how atmospheric control modulates ARR and structural evolution, offering an effective strategy for developing high-performance Li-rich cathodes.

Multistep redox reactions at the cathode interface in lithium-sulfur (Li-S) batteries face significant challenges related to mass transfer and the conversion of lithium polysulfides, particularly under conditions of high sulfur loading and high charge/discharge rates. In this study, we proposed a novel sulfur host material, hierarchical pore carbon nanocages (e-CoTe@NC), which were strategically designed with embedded cobalt telluride (CoTe) nanoparticles. The unique morphology of these nanocages, featuring hollow cavities and hierarchical pores, facilitated enhanced mass transfer, while the embedded CoTe nanoparticles catalyzed the rapid conversion of lithium polysulfides. The chemical coordination environment of the CoTe catalytic active center was characterized using X-ray absorption fine structure (XAFS) analysis. Electrochemical tests confirmed its high lithium ions diffusion capability. As a result of these advantageous properties, Li-S batteries assembled with the e-CoTe@NC host delivered a high initial capacity of 1355 mAh g-1 at 0.2 C and maintained a discharge capacity of 669.5 mAh g-1 after 500 cycles at 1 C. Furthermore, in-situ Raman spectroscopy was employed to monitor in real-time the types and contents of soluble lithium polysulfides (LiPSs) on the negative electrode, providing insights into the specific processes and key factors driving the shuttle effect. For the e-CoTe@NC batteries, significantly weaker Raman signals were detected at 275 cm-1 (long-chain S82-) and 455 cm-1 (intermediate-chain S42-), which indicated inhibited generation and enhanced adsorption of polysulfides. This work presents a promising strategy for developing sulfur hosts that enhance both mass transfer and catalytic conversion, offering potential applications in high-performance Li-S batteries.

The ion transport properties of the solid electrolyte interphase (SEI) critically govern the kinetics and cycling stability of rechargeable batteries. However, a mechanistic understanding of ion transport within this dynamic, multicomponent interphase remains limited. In this study, we demonstrate that spatial variations in the internal electric field across the SEI dictates a fundamental transition in Na+ transport mechanisms. Within the thin SEI region adjacent to the electrode, a strong electric field dominates, enabling ballistic Na+ transport with minimal scattering and thus facilitating rapid ion migration. In contrast, in thicker SEI regions where the electric field is attenuated, frequent ion collisions dominate, resulting in diffusive transport and reduced ion mobility. To validate this mechanism, we combined molecular dynamics and density functional theory simulations to evaluate electrolyte reducibility based on salt-solvent interactions. These computational insights are complemented by in situ, nondestructive potentiostatic chronocoulometry technique to quantitatively determine SEI formation charge. A systematic evaluation of 23 representative electrolytes reveals a strong correlation between SEI formation charge and SEI resistance (RSEI), consistent with the electric-field-dependent ion transport model (R2 = 0.993). Notably, eight electrolytes exhibit SEI formation charges below 50% and low RSEI, proving suppressed SEI formation promotes ballistic Na+ migration. The optimal electrolyte, 1 M NaPF6 in tetraethylene glycol dimethyl ether (TEGDME), forms a ∼21 nm SEI with merely 31.7% charge loss. Na||hard carbon cells using this electrolyte achieve 24.48 Ω cm2 interfacial impedance and retain 99.4% capacity after 1200 cycles. This work offers a mechanistic framework for designing high-performance interphases through electrolyte engineering.

Point defect engineering is a powerful strategy to manipulate charge redistribution in biochar. Herein, dominant C-S-C point defects are successfully constructed on vacancy- and edge-rich carbon within a three-dimensional (3D) honeycomb-like hierarchical porous framework through KOH etching and S doping strategies. Benefiting from its hierarchical porosity, large specific surface area, numerous vacancies, active C-S-C sites, high defect density and favorable wettability, the as-prepared biochar catalyst delivers excellent oxygen reduction reaction (ORR) activity. SNAC-6 achieves a half-wave potential of 0.84 V and a kinetic current density of 7.67 mA cm(-2) at 0.80 V, along with outstanding durability (only 13.7% current decay after chronoamperometry tests). The flow zinc-air battery (ZAB) assembled with SNAC-6 presents great application potential, with a high specific capacity of 544 mAh gZn(-1). DFT results reveal that C-S-C point defects on vacancies and exposed edges are the primary active sites for ORR catalysis. Meanwhile, defective carbon and N dopants synergistically modulate the electronic structure, further improving catalytic performance. This work deepens the understanding of point defect effects and offers a feasible route to rationally tailor the electronic and porous structures of biochar electrocatalysts.

Solid-state polymer electrolytes are plagued by low ionic conductivity, narrow electrochemical windows, and poor mechanical strength. Despite the effectiveness of incorporating inorganic fillers, conventional inorganic particles still face the challenges of limited specific surface area, weak interfacial interaction, and ease of agglomeration. To address these limitations, we develop a mechanically interlocked TP-SiO2 nanofiller by introducing terephthalaldehyde (TA) and 1,4-phenylenediamine-2-sulfonic acid (Pa-SO3H) into SiO2 aerosols through an in situ Schiff base reaction, thereby achieving a high specific surface area and superior interfacial compatibility. Unlike conventional fillers, TP-SiO2 filler acts not only as a nucleating agent to suppress the crystallization of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) but also provides sulfonate groups (SO32-) that facilitate lithium salt dissociation and enhance lithium-ion transport, thereby synergistically overcoming issues of low conductivity and high polarization. Consequently, the fabricated PVDF-HFP@TP-SiO2-LiFSI (PTSL) electrolyte achieves a high ionic conductivity of 5.48 & times; 10-4 S cm-1 at room temperature, a Li* transference number of 0.42, and a broad electrochemical stability window up to 4.7 V vs. Li*/Li. The Li||Li symmetric cell demonstrates stable cycling for over 1200 hat 0.1 mA cm-2. Furthermore, full cells paired with LFP and NCM811 cathodes exhibit desirable electrochemical performance, especially long-term cycling stability.

The global drive toward carbon neutrality is accelerating demand for high-energy-density lithium-ion batteries,driving interest in lithium-rich layered oxides(LLOs)as cathodes.LLOs uti-lize combined cationic and anionic redox to achieve capacities exceeding 250 mAh g-1,surpassing conventional cathodes[1].

Partial lithiation has emerged as a promising strategy to mitigate the volume expansion in silicon anodes. However, current implementations predominantly rely on externally imposed constraint approaches and inevitably sacrifice substantial capacity. Herein, an innovative self-limiting partial lithiation strategy driven by interfacial heavy doping is proposed. Through ice-templated self-assembly of sol particles, the localized high-concentration P-doping is achieved at interconnected particle interfaces in 2D holey Si nanosheets. This interfacial heavy doping triggers a "region-selective lithium shielding" effect, enabling in situ passivation and sustained retention of trace crystalline silicon domains during cycling. These retained crystalline domains, with dual characteristics of electrochemical inertness and self-buffering mechanism, effectively mitigate the volume expansion of silicon anodes while causing only minimal capacity loss. Thanks to the partial lithiation behavior in holey self-assembled nanosheets, the P-doped silicon anode demonstrates remarkable cycling stability (2176.2 mAh g-1 after 200 cycles at 0.5 A g-1). Although P-doping locally impedes Li+ transport in heavily doped regions, it significantly promotes lithium-ion kinetics in P-poor/P-free domains. Coupled with the improved electron conductivity, this synergy effect leads to superior rate capability (1590 mAh g-1 at 2 A g-1).

Layered oxide cathode with a Li‐O‐vacancy configuration offers high capacity by leveraging additional oxygen redox reactions. However, it faces severe challenges of sluggish kinetics of oxygen redox reactions and lattice oxygen loss, resulting in slow Li + diffusion and rapid electrochemical degradation. Herein, Ti is introduced as electrochemical inactive element into Li‐O‐vacancy configuration to form Mn/vacancy/Ti arrangement within transition metal layers of layered oxide, achieving a marked increase in average output voltage at high current density compared with Ti‐free counterpart. Not only voltage hysteresis between charge and discharge processes can be significantly reduced, but rate capability can be heightened in Li 4/7 [□ 1/7 Ti 1/7 Mn 5/7 ]O 2 by means of retrained over‐potential and improved Li + diffusivity. Furthermore, theoretical calculations suggest that these improvements stem from Ti substitution, which elongates the Li─O bond and lowers the Li + migration energy barrier. Besides, in situ differential electrochemical mass spectrometry and soft X‐ray absorption spectroscopy reveal the modified Li‐O‐vacancy configuration enables reversible anionic and cationic redox behaviors during cycling. These findings provide a promising strategy for tailoring oxygen redox activity and accelerating Li + diffusion kinetics in layered cathode materials with oxygen redox chemistry.

While fine-tuning services drive the rapid expansion of task capabilities in large language models (LLMs), they are often accompanied by the degradation and reorganization of safety-aligned representations, making models more prone to deviating from human preferences and exposing them to emerging jailbreak risks. Existing post-fine-tuning defense methods predominantly rely on single-scale safety correction mechanisms, which struggle to achieve a robust balance among safety, model utility, and continual adaptability. We propose Multi-Level Safety Continual Projection (MSCP), a training-free post-fine-tuning safety enhancement method that implicitly aligns global and localized safety activations through coordinated multi-level representations to isolate sparse neuron clusters governing safety-sensitive behaviors. It then applies composable safety-direction projections without retraining, effectively suppressing harmful outputs under minimal parameter perturbations while preserving task performance and improving alignment with human preferences. Extensive experiments across multiple fine-tuned LLM models demonstrate that our method significantly reduce harmfulness scores and attack success rates with minimal parameter modifications, while preserving the model's utility. Furthermore, we introduce a task-specific, multi-dimensional heterogeneous safety activation clustering mechanism that enables continual defense and generalization capability against unforeseen emerging safety concerns.

Metal hexacyanoferrates (MHCFs) are promising cathodic candidates for commercial sodium-ion batteries, but still suffer from unsatisfied electrochemical performance owing to inherently low crystallinity of liquid-based MHCF products. Herein, a solid-state reaction route has been developed to synthesize MHCFs with enhanced crystallinity. Moreover, the compositional features of the MHCFs have been rationally designed, and five different active and inert transition-metals, especially Zn with ZnN4 tetrahedron coordination structure, are incorporated into a single high-entropy FeMnCoNiZn-HCF. Thanks to the high crystallinity and optimized composition, the solid-state derived high-entropy MHCF cathode manifests good electrochemical Na-storage performances in terms of reversible capacity, cyclic life, and rate capability.

Single-crystal (SC) Li-rich cathodes have demonstrated superior structural and electrochemical stability compared to their polycrystal (PC) counterparts. However, the principles governing the solid-state synthesis of SC Li-rich oxides remain elusive, and the growth mechanisms of SC cathodes are still poorly understood. Herein, a prototype Li-rich layered oxide, Li1.2Ni0.13Co0.13Mn0.54O2, was synthesized with well-dispersed SC morphology through the regulation of Li excess content during solid-state reactions. This approach facilitated a solid-state exfoliation growth process, transforming spherical secondary particles into monodisperse primary SC oxides. Furthermore, two diffusion pathways of Li source—boundary diffusion and grain diffusion—were proposed to elucidate the underlying mechanisms driving SC exfoliation during solid-state reactions. This understanding enables the flexible synthesis of both PC and SC Li-rich cathodes. Compared to traditional PC counterparts, severe irreversible oxygen release, crack formation, and the transition from layered to spinel phases were effectively suppressed within the exfoliated SC cathode, resulting in an extended battery lifespan with a capacity retention of 93.6% over 500 cycles at 1 C. These findings provide practical methodology and mechanism insights for the synthesis and design of high-energy-density and high-stability Li-rich cathodes.

Prussian blue analogues, particularly metal hexacyanoferrates with double octahedral coordination (DOC) structures, hold great promise as cathode materials for sodium-ion batteries. However, their practical application is hindered by limited structural stability and restricted ionic diffusion channels inherent to the DOC structure. In this study, we have successfully integrated a mixed tetrahedral and octahedral coordination (TOC) structure with the DOC structure by a dual polymerization and high-entropy strategy, thereby optimizing the central metal coordination environment in hexacyanoferrate cathodes. It leverages the TOC structure's superiorities in structural stability and ionic diffusion, resulting in a hexacyanoferrate-based cathode that exhibits exceptional performance, with a capacity retention of 81.6% after 1000 cycles at 0.5 A g-1 and high rate capabilities of 96.7 and 89.1 mAh g-1 at 0.5 and 1 A g-1, respectively. These findings not only underscore the potential of the TOC design for prussian blue cathodes but also pave the way for the development of high-performance, durable sodium-ion battery systems.

The continuous and conformal carbon coating on nanoporous silicon is very effective in enhancing the structural stability and charge-transport capability of silicon-based anodes. Herein, a double-network gel-derived magnesiothermic reduction route has been developed for continuously coating carbon on nanoporous silicon, yielding bicontinuous Si/Mn4Si7@C (Si-Mn-C) ternary material. Thanks to the conformal carbon coating, inactive Mn4Si7 hybridization, and gel-derived nanoporous structure, the bicontinuous Si-Mn-C anode manifests good cycling stability (1445 mA h g-1 after 100 cycles at 0.5 A g-1) and high rate performance (1305 and 1108 mA h g-1 at 5 and 10 A g-1, respectively).

Al-V alloy was firstly prepared by arc melting followed by grinding using a stainless steel mortar. The alloy is mainly made up of Al3V, together with a little amount of Al8V5 and Al, and the particles in range of 1-30 mu m. Among the MgH2-Al3V composites with Al3V concentrations of 1, 5 and 7 wt%, the MgH2-5 wt% Al3V composite exhibits the best hydrogen absorption and release kinetic performance. The MgH2-5 wt% Al3V composite can absorb 5.9 wt% of hydrogen within 3600 s at a temperature of 523 K. Despite the lower temperature of 423 K, it can also uptake hydrogen 1.71 wt% in 3600s. During dehydrogenation, MgH2-5 wt% Al3V releases 6.52 wt% of hydrogen in 350s at 673 K. The initial dehydrogenation temperature was lowered to 564 K. The activation energies of hydrogenation and dehydrogenation for MgH2-5 wt% Al3V composite are 87.98 kJ/mol and 85.57 kJ/mol, respectively. And the Al3V remains unchangeable in the hydrogen absorption/desorption cycle. After 20 cycles, the retention of hydrogenation and dehydrogenation capacity was 97% and 99%, respectively. The presence of Al3V and oxygen vacancies plays an important role in the improvement of hydrogen storage properties of MgH2. This study provides new ideas for the designing Al-V alloy catalyst for enhancing hydrogen storage performances of MgH2.

Metal hexacyanoferrates (MHCFs) have emerged as promising cathodes for sodium-ion batteries. However, conventional wet-chemistry-derived MHCFs inevitably contain substantial Fe(CN)6 vacancies and crystal water, resulting in an undesirable Na-storage performance. Herein, a gel-confined crystallization strategy is developed to prepare highly crystalline MHCFs. In a typical polypyrrole (PPy) gel, the cross-linked network effectively restricts the movement of internal ions through steric hindrance and attractive/repulsive interactions, leading to slow crystal growth and formation of highly crystalline MHCFs. Specifically, iron hexacyanoferrate (FeHCF), with only 1% Fe(CN)6 vacancy and 2.0 wt% crystal water, has been formed in situ within a PPy gel via this gel-confined crystallization process. The highly crystalline FeHCF coupled with an interconnected PPy framework enables the hybrid cathode to exhibit enhanced activity of low-spin Fe sites, long cycling life, and good rate capability.

Based on the experimentally reported stable and conductive two-dimensional covalent organic frameworks with copper phthalocyanine (CuPc) as building block and cyan substituted phenyl as connector (CuCOF-CN) as an electrocatalyst for CO2 reduction reaction (RR), first principle calculations were performed on CuCOF-CN and its analog with the CN being replaced by H (CuCOF). Comparatively studied on the crystal structures, electronic properties, and CO2RR performance of the two catalysts found that CuCOF has reduced crystal unit size, more positive charge on Cu and CuPc segments, smaller band gap, and lower reaction barrier for CO2 RR than CuCOF-CN. CuCOF is proposed to be good potential electrocatalyst with good environment friendliness. The substituent effect and structure-property-performance relationship would help for designing and fabricating new electrocatalysts.

Sodium-ion batteries (SIBs) represent a promising energy storage technology with great safety. Because of their high operating potential, superior structural stability, and prominent thermal stability, polyanion-type phosphates have garnered significant interest in superior prospective cathode materials for SIBs. Nevertheless, the disadvantages of poor intrinsic electronic conductivity, sluggish kinetics, and volume variation during sodiation/desodiation remain great challenges for satisfactory rate performance and cycle stability, which severely hinder their further practical applications. In this work, by adjusting the amounts of pretreated multiwalled carbon nanotubes (CNT) added intentionally at the beginning of the preparation, biphasic polyanion-type phosphate materials (marked as NFC) are synthesized through a one-pot solid state reaction methodology, which are composed of CNT-interwoven Na3V2(PO4)(2)F-3 (NVPF) and a small amount of Na3V2(PO4)(3) (NVP). Benefiting from the improved electronic conductivity and unique composition and structure, the optimized sample (labeled as NFC-2) illustrates exceptional cycle stability and remarkable rate performance. The discharge capacities of the NFC-2 electrode are 114.8 and 78.6 mAh g(-1) tested at 20 and 5000 mA g(-1), respectively. Notably, such an electrode still gives out 75.7% capacity retention upon 10 000 cycles at 5000 mA g(-1). In situ X-ray diffraction analysis demonstrates that the NFC-2 cathode has outstanding structural reversibility during charge/discharge cycles. More importantly, such a biphasic material has achieved impressive electrochemical performance within a wide operating temperature range of -20-50 degrees C. When temperature is decreased to -20 degrees C, the NFC-2 electrode still delivers an initial discharge capacity of 102.4 mAh g(-1) and exhibits a remarkable capacity retention of 97.8% even after 500 cycles at 50 mA g(-1). In addition, the sodium-ion full cell assembled by integrating NFC-2 cathode and hard carbon anode shows a satisfying energy density of 431.3 Wh kg(-1) at 20 mA g(-1) with a better long-term cycle performance. The synergistic effect among high energy NVPF, conductive CNT, and stable NVP may lead to the great improvement in the electrochemical sodium storage performance of the NFC-2 sample. Such biphasic polyanion-type phosphate materials will inject new ideas into the material design for SIBs with excellent electrochemical performance and further promote practical applications of this advanced energy storage technology.