Directional thermal transport materials enable anisotropic heat flow, thereby enhancing the efficiency of thermal management systems. These materials have found broad applications in aerospace, electronics, and automotive industries. Silicon carbide (SiC) based composites, with their exceptional properties including high modulus, thermal stability, and superior thermal conductivity, serve as an ideal structural material. Strategic manipulation over microstructure and composition enables directional thermal management, expanding applicability in thermal management and achieving structural-functional integration. By combining selective laser printing with precursor impregnation and pyrolysis (PIP), this work presents an innovative approach to fabricating thermally anisotropic C_f/SiC composites that integrate both structural and functional properties. The optimized composite (20% (in volume) chopped C_f) exhibited high fiber alignment (f_p = 0.7677) and pronounced thermal anisotropy, with thermal conductivities of 70.14 W/(m·K) perpendicular and 38.87 W/(m·K) parallel to the printing plane (anisotropy ratio: 1.8). This directional heat transport, enabled by fiber orientation and phonon scattering control, is critical for advanced thermal management. The composite also maintained good mechanical strength, exhibiting a flexural strength of (150.4 ± 9.8) MPa parallel to the printing plane, finalizing in a structural and functional integration.

Density Functional Theory (DFT)-derived electronic descriptors are key to accelerating the design of effective ORR/OER catalysts. The O 2p-band center, in particular, is a robust descriptor of catalytic activity in perovskite oxides. This study examines the O 2p-band center in Fe⁴⁺ perovskite-type layered oxides, focusing on the Ruddlesden Popper (RP) phases Sr₂FeO₄ and Sr₃Fe₂O₇, as well as the high-Tc superconductor YSr₂Cu₂FeO₈. The analysis emphasizes trends driven by compositional modifications. The O 2p-band centers of Sr_2-2xLa_2xFeO₄ and Sr_3-3xLa_3xFe₂O₇ (0 < x < 1) correlate linearly with the Fe oxidation state, and span a wide energy range (-1.2 eV to -4.7 eV with PBE+U; -1.9 eV to -4.7 eV with SCAN). Partial substitution of Fe with 3d transition metals (TM) in Sr₂Fe_7/8xM_1/8O₄ shifts the O 2p band center, with the more electronegative TMs bringing it closer to the Fermi level. RP-Sr₂FeO₄ exhibits remarkable tunability of the O 2p-band center, enabling the compositionally driven design of oxygen catalysts with potentially improved activity-stability balance. In contrast, YSr₂Cu₂FeO_7+δ (0 < δ < 1) shows no correlation between the O 2p-band center and Fe oxidation states, likely due to a change in Fe coordination from octahedral (δ = 1) to tetrahedral (δ = 0). The O 2p-center values (-0.9 eV to -1.3 eV with PBE+U; -1.5 eV to -2 eV with SCAN) suggest that YSr₂Cu₂FeO_7+δ could potentially catalyze the ORR/OER, though stability over operation time remains a challenge.

Transparent thermoelectric CdO thin films exhibit critical flexibility and thermoelectric performance that require focused research to advance flexible transparent self-powered devices. Here, we demonstrate the superior flexibility of freestanding single-crystalline CdO membranes. These membranes achieve a notable room-temperature power factor of 1.48 μW·cm^-1·K^-2 and exhibit superior optical transmittance exceeding 94% in the 550-800 nm range. Crucially, freestanding CdO exhibits exceptional mechanical robustness, retaining >90% electrical conductivity after 1000 bending cycles (radius: 11.5 mm). Microstructure analyses confirm polycrystalline CdO films suffer from grain boundary cracking under bending due to stress concentration, but single-crystal CdO membranes-without grain boundaries to concentrate stress-exhibit better flexibility and resistance to cracking. Furthermore, curvature-induced strain boosts the power factor by 12.8%, providing a curvature-controlled strain engineering strategy to optimize flexible thermoelectric performance. This work establishes free-standing CdO as a highly efficient and flexible thermoelectric material and suggests a fundamental strategy for designing robust smart materials for transparent, self-powered flexible electronics.

Aromatic polyimide (PI) with high glass transition temperature (T_g) shows promise as a polymer dielectric for energy storage, but its rigid aromatic structure and electron delocalization cause significant conduction loss, degrading energy storage performance and breakdown strength (E_b) under high temperatures. Herein, we introduce a novel semi-alicyclic fluorinated polyimide (H-FPI) designed via a molecular engineering strategy that synergistically integrates bandgap and topological conformation modulation. Specifically, the alicyclic group elevates the lowest unoccupied molecular orbital (LUMO) while strong electron-withdrawing trifluoromethyl (-CF₃) substitution depresses the highest occupied molecular orbital (HOMO), creating a wide bandgap (4.2 eV). Concurrently, the chair-conformation alicyclic backbone and sterically bulky -CF₃ groups synergistically disrupt molecular planarity, reducing π-orbital overlap to suppress charge transfer while restricting chain mobility to yield a high T_g of 272 ℃. Remarkably, H-FPI film delivers a high energy density of 6.02 J/cm³ with a superior breakdown strength of 626 MV/m at 200 ℃, surpassing commercial PI and fluorinated polyimide (FPI) by 1261% and 55%, respectively. Furthermore, H-FPI film exhibits exceptional capacitor charge-discharge cyclability, enhanced mechanical robustness, and excellent thermal stability. This work establishes a new molecular design paradigm for organic capacitors in electrffied transportation and smart grid systems requiring high-temperature working reliability.

The development of high-performance lead-free energy storage capacitors is crucial for sustainable technologies, yet hindered in NaNbO₃-based antiferroelectric (AFE) ceramics because of significant polarization hysteresis from field-induced AFE-ferroelectric (FE) phase transitions. This hysteresis fundamentally limits the simultaneous optimization of recoverable energy density (W_rec) and efficiency (η). Herein, we demonstrate that lamellar nanodomain engineering via compositional design in a (0.87-x)NaNbO₃-0.13Bi_0.5Na_0.5TiO₃-xBi(Mg_0.5Ti_0.5)O₃ system effectively overcomes this bottleneck. The optimized composition (x = 0.05) delivers exceptional energy storage performance with a W_rec of ~8.2 J/cm³, a η of ~88.9%, and a power density of ~207 MW/cm³. Analysis on multiscale structure evolution reveals that this compositional tuning induces a phase transformation from AFE P to AFE R symmetry, accompanied by an enhanced local structural disorder. Critically, the formation of lamellar AFE R-phase nanodomains with width ranging from 2 nm to 6 nm drives a quasi-linear polarization response with minimal hysteresis. Concurrently, the refined grain size improves the ceramic resistivity, substantially enhancing dielectric breakdown strength. These synergistic effects collectively yield outstanding energy storage properties, demonstrating that engineering lamellar AFE R-phase nanodomains is an efficient strategy to optimize overall energy storage performance of NaNbO₃-based materials.

In this study, we propose grain boundary engineering and nanostructuring to enhance the thermo-electric performance of SnTe through tri-doping with Mn, Ge, and Bi. The synergistic effects on the band structure were analyzed through DFT calculations and validated through a series of doping experiments with each dopant. The nonstoichiometrically tri-doped sample exhibits a unique microstructure, characterized by Mn-Ge precipitates along the grain boundaries and coherently embedded nanostructures within the matrix. These microstructural features, combined with the effects of each dopant, synergistically enhanced the thermoelectric properties, yielding a maximum zT of 1.32 at 873 K. The thermoelectric generator exhibited a maximum output power of 661 μW at ΔT = 485 K, confirming its viability for mid-temperature thermoelectric applications.

A series of (Sr_0.4Ce_0.4)TiO₃ + 4% (in mass) Sr₂CeO₄ + x% B₂O₃ (SCTO + 4% SCO + x% B₂O₃ for 1≤ x ≤ 5) composites were synthesized via solid-state reaction to investigate the effects of Sr₂CeO₄ and B₂O₃ additives on their structural evolution and microwave dielectric properties. X-ray diffraction (XRD) and Rietveld refinement confirmed the dominant orthorhombic phase (O-phase), with SCO as a secondary phase, indicating a chemically stable composite system. HRTEM and SAED analyses further confirmed the formation of the O-phase through direct observation of the superlattice reflections. Microstructural evolution demonstrated B₂O₃-assisted liquid-phase sintering, reducing porosity (0.017 → 0.006) and increasing grain size (3.34 → 6.01 μm) with increasing x% (in mass). Raman spectroscopy verified octahedral tilting and Ce-O stretching, while B₂O₃ incorporation modified the TiO₆ network via BO₃/BO₄ interactions. The ε_r decreased from 113 (SCTO) to 27 at x = 5%, while τ_f improved from +213 to +12 × 10^-6/℃. The reduction in ε_r arises from a complex interplay of internal factors (ionic polarizability) and external factors (porosity, and density), whereas the variation in τ_f is governed by compensating effects from Sr₂CeO₄ and B₂O₃. Optimal microwave performance was achieved at x = 5%, with Q×f = 43,603 GHz, ε_r = 27, and τ_f of +12 × 10^-6/℃. The study demonstrates that SCO and B₂O₃ act as effective modifiers, enhancing densification and dielectric properties in SCTO-based microwave ceramics.

Defect engineering is a key strategy for optimizing the thermoelectric (TE) properties of PbTe-based materials, and investigating charged defects in PbTe grain boundaries (GBs) is crucial for understanding its thermoelectric properties. In this study, focusing the GBs, we perform a high-throughput investigation of the formation energies with various charged point (intrinsic and extrinsic) defects and their effects on the mechanical properties, the shear modulus. The GBs can facilitate the formation of the charged point defects (such as , ), indicating the accumulations of the defects within the GBs region. Such defect accumulation can strongly increase the phonon scatterings. Furthermore, charge defects within Te-PbTe GBs lower the shear modulus to <33.1 GPa, due to the weakening interactions between Pb-Te bonds. The soft bonds around GBs will induce the stronger anharmonicity and further suppress the lattice thermal conductivity. Employing the machine learning method, we establish the relationship between the shear modulus and physical descriptors, which can efficiently screen or design the various purposes of PbTe compounds. Our work bridges the gap in understanding charged defects at grain boundaries in PbTe-based thermoelectric materials and giving rise to the design methodology to achieve high promising thermoelectric performance through charged defect influenced mechanical properties.

The utilization of hybrid ion batteries (HIBs) effectively reduces the consumption of scarce Li resources and harnesses the synergistic effect of mixed ions to achieve performance comparable to that of lithium-ion batteries. However, there is currently a lack of anode materials that possess both high safety and excellent performance for HIBs. Herein, we present a novel structure of enclosed hard carbon nanotubes (HCNTs) doped with high levels of nitrogen and oxygen as anodes for HIBs. When utilized in Li-Na-K HIBs, they exhibit superior reversible capacity (440.1 mA·h·g^-1 at 100 mA/g) and enhanced rate performance (327.7 mA·h·g^-1 at 1 A/g) compared to single alkali metal ion batteries. These improvements can be attributed to the design of a one-dimensional structure that features highly doped hard carbon, which significantly enhances carrier transport. Furthermore, first-principles calculations reveal the synergistic effect of hybrid ions in nitrogen-doped hard carbon nanotubes, enhancing the ion adsorption stability in the carbon layer. This study introduces a substantial anode material for HIBs and expands the scope from binary to ternary HIB systems.