Xiaoyan Ma

Although low‐temperature (≤ 100°C) curing of alicyclic epoxy resin (CEP) avoids the cracking issues associated with high‐temperature (120°C–180°C) curing, the resulting material still suffers from insufficient toughness. To address this limitation, it is typically necessary to introduce a second‐phase modifier or incorporate flexible segments into the resin structure. However, conventional second‐phase modifiers tend to compromise other desirable properties—such as heat resistance—or suffer from poor dispersion within the epoxy matrix. Herein, an aliphatic side‐chain epoxy resin (BD‐S‐182) and an aliphatic side‐chain epoxy bisphenol A (DGEBDDBA) are synthesized to improve the mechanical properties and thermal resistance of the material at the molecular level through cross‐linking. Both BD‐S‐182 and DGEBDDBA can enhance the impact strength and elongation at break of cycloaliphatic epoxy resin (2021P) without altering the original low‐temperature curing mechanism. The best impact resistance strength of BD‐S‐182 and DGEBDDBA is 45.1 and 52.4 kJ/m ² , increasing by 226.8% and 279.7%, and the elongation at break can reach 43.71% and 51.36%, increased by 168.8% and 215.9%, respectively, compared with low‐temperature curing virgin resin. The thermal decomposition temperature ( T _d5% ) of DGEBDDBA with 10 wt% is increased from 226.3°C to 275.1°C, and that of BD‐S‐182 with 30 wt% is increased to 241.7°C.

To clarify the microscopic mechanism by which 1,1-diamino-2,2-dinitroethylene (FOX-7) improves the safety of 3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) and to address the limited quantitative precision of conventional mechanical-sensitivity metrics, FOX-7/DNTF composite molecular models were first established. Quantum-chemical calculations were performed to obtain atomic charges (q), bond lengths (λ), and bond orders (n) and to identify the trigger bond of DNTF. The stability of DNTF before and after introducing FOX-7 was evaluated using the trigger-bond charge difference (△q), maximum electrostatic-potential difference (△Vs), frontier molecular-orbital energy gap (△ε), and chemical hardness (η), thereby elucidating the microscopic desensitization mechanism. FOX-7/DNTF bulk crystal models were then constructed, and the fractional free volume (FVF), interfacial binding energy per unit area (Wbind), and cohesive energy density (CED) were calculated to examine safety-related changes from structural and energetic perspectives and quantitatively characterize mechanical sensitivity. Molecular dynamics simulations were further conducted to reproduce impact and friction loading. Mean-square displacement (MSD), dipole autocorrelation function (DACF), stress autocorrelation function (SACF), and statistical descriptors of trigger-bond lengths were introduced to dynamically evaluate structural stability throughout mechanical loading. Comparison with experimental sensitivity data supports the consistency and applicability of these descriptors.

The rapid advancement of aerospace technology demands electromagnetic interference (EMI) shielding materials that maintain reliable performance under severe thermo‐mechanical conditions, such as sustained high temperatures and thermal shock. Phenolic resin (PR) stands out as a highly suitable matrix material, especially for carbon‐based composites, thanks to three key features: (i) good thermal stability from high char yield. (ii) strong ability to combine with various functional fillers. This review introduces the basic principles of EMI shielding and explains the influence of phenolic resin's structural designability on shielding performance. Furthermore, it addresses two primary strategies: intrinsic shielding via molecular backbone modification of PR, and composite shielding by incorporating new functional fillers. On this basis, the concept of multifunctional collaborative design is further proposed, which integrates EMI shielding with high‐temperature resistance, thermal insulation, ablation resistance and mechanical load‐bearing properties to match the complex extreme service requirements of aerospace scenarios. Both approaches and their synergistic extension toward multifunctionality are examined systematically. In summary, although PR‐based composites outperform conventional polymers in high‐temperature EMI shielding, they still face major challenges: filler‐matrix interfacial problems and insufficient validated in situ high‐temperature performance data, which need to be solved for practical deployment from lab prototypes.

The large‐scale application of aqueous zinc‐ion batteries (AZIBs) is impeded by critical challenges, including uncontrolled zinc dendrite growth, severe parasitic side reactions, and hydrogen evolution reaction. To address these issues, we introduce a versatile diprotic acid, malonic acid (Mal), as a functional electrolyte additive. Combined experimental and theoretical results, we propose a new “etching‐adsorption‐deposition” mechanism, where Mal and its protons synergistically form a dendrite‐free, (101)‐oriented Zn anode. Concurrently, Mal participates in the Zn ²⁺ solvation sheath, effectively inhibiting water activity and hydrogen evolution reaction. These synergistic effects endow it with outstanding electrochemical stability, the Zn//Zn cell exhibits ultra‐long cycle stability over 4700 h at 5 mA cm ⁻² and 1 mAh cm ⁻² . Furthermore, the Zn//Cu cell delivers a significantly improved reversibility with an average Coulombic efficiency (CE) of 99.86% after 2000 cycles at 5 mA cm ⁻² and 1 mAh cm ⁻² . Surprisingly, Mal molecules exhibit a strong affinity for the V ₂ O ₅ cathode, forming a protective layer that mitigates vanadium dissolution and suppresses parasitic by‐products. The Zn//V ₂ O ₅ full cell consequently demonstrates excellent cycling performance, with 98.25% capacity retention after 1000 cycles at 1 A g ⁻¹ . Notably, its stability extends to extreme conditions, as it also maintains 64.5% capacity retention after 5000 cycles at 10 A g ⁻¹ .

The crystal morphology and particle size distribution of high-energy molecular crystals are critical parameters governing their processability and structural integrity in composite explosive formulations. Despite extensive studies on solvent effects, the mechanistical framework linking solvent–antisolvent environments to crystal growth anisotropy remains insufficiently developed. In this work, the recrystallization behavior of 3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) was systematically investigated by considering antisolvent concentration-temperature double factor coupled modeling in ethyl acetate (EAC)/water (H₂O) systems. Molecular dynamics simulations were employed to quantify and evaluate solvent-dependent parameters and relative growth tendencies of dominant DNTF crystal faces as functions of EAC/H₂O mass ratio and crystallization temperature. The results reveal that H₂O, acting as antisolvent additive, enhances selective adsorption on different crystal faces, amplifying growth-rate disparities and promoting anisotropic morphologies. In contrast, increasing temperature weakens solvent adsorption, leading to convergence of relative growth rates and reduced morphological anisotropy. Based on these insights, a crystallization window favoring near-equiaxed DNTF crystal habits (EAC/H₂O = 1:1, 65 °C) was theoretically identified. Recrystallization experiments were conducted under the window, where stirring rate was used to modulate nucleation and growth kinetics. DNTF crystals with tunable specific particle sizes and aspect ratios were successfully obtained. X-ray diffraction and energy-dispersive spectroscopy confirmed that the recrystallization process altered crystal morphology and size without changing the crystal structure and form. This study establishes a solvent–antisolvent-assisted strategy for regulating the crystal habit of DNTF and provides mechanistic insights into solvent-mediated crystal growth, offering theoretical guidance for the controlled preparation of energetic material crystals.

Boron‐modified phenolic resin composites are critical aerospace thermal protection materials due to their ability to form boron‐containing ceramic layers during ablation, which provides exceptional ablation resistance. This article systematically reviews recent research progress on boron‐modified phenolic resin ablation‐resistant composites from two primary design perspectives. Firstly, from the perspective of the resin matrix level, strategies for chemically bonding boron elements to phenolic resins are summarized. Using boron‐containing compounds like boric acid or phenylboronic acid introduces high‐bond‐energy BO bonds, fundamentally enhancing the resin's thermal stability and performance under extreme conditions. Building on this, introducing boron‐containing ceramic precursors into phenolic resins can further optimize their ablation resistance and high‐temperature performance. Secondly, at the composite level, the incorporation of single‐ or multiphase boron‐containing ceramic fillers is reviewed. These fillers enable the in situ development of high‐viscosity molten ceramic layers during ablation, exhibiting exceptional thermal stability and ablation resistance. Finally, the fundamental mechanisms governing the thermal resistance and enhanced ablation achieved through both chemical modification and the introduction of ceramic reinforcing phases are summarized.

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) still face critical challenges in all-solid-state lithium-ion batteries, including insufficient ionic conductivity and inherent flammability. To overcome these limitations, a flame-retardant SPE (PA-SPE) was developed by incorporating ammonium polyphosphate (MAPP) encapsulated in a rigid-flexible polyurethane shell into the PEO. The rigid-flexible polyurethane shell surrounding MAPP serves as a protective barrier that mitigates undesirable reactions between the flame retardant and lithium metal, while simultaneously acting as a thermally responsive layer that enables the controlled release of flame-retardant species at elevated temperatures, allowing the PA-SPE to achieve rapid self-extinguishing within 1s. Compared with pristine PEO, the mechanical strength of PA-SPE is enhanced by a factor of 2.6. More importantly, the incorporation of MAPP markedly improves the ionic conductivity of the PA-SPE, reaching 1.012 × 10 ^–4 S cm ⁻¹ at 30 °C. The electrochemical stability window of PA-SPE is extended to 4.8 V, while the Li ⁺ transference number is significantly enhanced to 0.41. Furthermore, Li‖LiFePO ₄ assembled with PA-SPE maintain 97.78% of the initial capacity after 200 cycles. The proposed strategy provides a universal solution for the development of all-solid-state lithium-ion batteries with high safety and long-cycle life.

In-situ polymerization of solid-state polymer electrolytes is a promising approach for achieving mass production of all-solid-state batteries. However, inferior ionic conductivity and separator infiltration limit practical applications. Inspired by the nutrient-transporting vascular bundles in plants, a biomimetic fluorinated nanocellulose/PVDF-HFP porous composite membrane of stacked parallel nanocellulose bundles wrapped by PVDF-HFP sheaths is designed and prepared. The nanocellulose bundles assembled of fluorinated cellulose nanocrystals and cellulose nanofibers through shear-induced alignment create low-curvature ion transport channels, while the PVDF-HFP sheath facilitates lithium salt dissociation and reinforces structural stability. Benefiting from this bundle-sheath structure, the composite membrane exhibits excellent ionic conductivity, stability, and electrolyte wettability. The polymer electrolyte prepared with this composite membrane has a high ionic conductivity of 2.46 × 10 ⁻⁴ S cm ⁻¹ (30 °C), an electrochemical stability window (5.3 V), and cycle stability. Consequently, Li||LFP cells can retain a superior capacity of 77.48% after 1000 cycles at 1 C, and Li||NCM811 cells can maintain 83.94% capacity after 300 cycles at 0.1 C. Moreover, pouch cells can withstand temperatures up to 130 °C without thermal runaway. This biomimetic strategy provides a promising pathway to advance cellulose separators for high-performance all-solid-state batteries.