Physics

Owing to their stable three-dimensional cross-linked network and excellent mechanical and electrical insulation properties, anhydride-cured epoxy resins are widely used in dry-type transformers. 1,5,7-triazidobicyclo[4.4.0]deca-5-ene (TBD), a common catalyst for the ring-opening reaction of anhydrides and transesterification reactions, is widely applied in anhydride-cured epoxy resins. However, the high crystallinity of TBD results in poor compatibility with epoxy-anhydride thermosets, causing precipitation during mixing and nonuniform curing of the resin. In addition, the strong basicity of TBD induces excessive reactivity, undesirably narrowing the processing window. To overcome these limitations, a thermally latent catalyst (PTBD) was designed and synthesized. PTBD remains chemically inert at room temperature, significantly extending the processing window. Upon heating to 120 °C, PTBD dissociates into TBD, which efficiently catalyzes the transesterification reaction, thereby imparting excellent dynamic reversibility to the cured resin. This study achieves the synergistic enhancement of processability (processing window exceeding 190 min at 80 °C), mechanical performance (tensile strength up to 102.82 MPa) and degradability (complete degradation at 130 °C for 4 h) in epoxy resin systems.

Most phosphate precursors used in atomic layer deposition are either thermally unstable or require activation. Therefore, our aim is to identify additional phosphate precursors that have not yet been widely used by the scientific community. This paper describes the deposition of titanium phosphate coatings via atomic layer deposition using in various pulse sequences titanium tetraisopropoxide (TTIP), tris(trimethylsilyl) phosphate (TTMSP), and water as the precursors. We performed the deposition predominantly onto carbon fibers. For x-ray photoelectron spectroscopy (XPS), in a limited number of cases, we coated flat silicon wafers, bearing 100 nm oxide layers. Film growth without a water pulse (pulse sequence TTMSP/TTIP) did not yield reliable results. Therefore, the pulse sequences TTMSP/H2O/TTIP, TTMSP/TTIP/H2O, and TTMSP/H2O/TTIP/H2O were used. All these sequences exhibited self-limiting growth behavior at 200 °C. The growth per cycle (GPC) was 0.21–0.24 nm/cycle for TTMSP/H2O/TTIP and TTMSP/H2O/TTIP/H2O, while TTMSP/TTIP/H2O yielded a lower GPC of 0.11 nm/cycle. Chemical analyses of the deposited coatings via induction coupled plasma-optical emission spectrometry (ICP-OES) and XPS revealed a molar ratio P/Ti in the range of 0.31–0.91. These values are lower than the value of 1.33, which is expected for Ti3/4PO4. Therefore, these coatings have compositions between titanium phosphate and titanium oxide. The coatings with the TTMSP/TTIP/H2O pulse sequence comprised the highest phosphorus content: XPS sum formula = TiP0.53O3.1C0.2, ICP-OES P/Ti = 0.52–0.91. The sequence TTMSP/H2O/TTIP yielded XPS sum formula = TiP0.38O2.8C0.3 and ICP-OES P/Ti = 0.32–0.45. The sequence TTMSP/H2O/TTIP/H2O yielded a similar composition with XPS sum formula = TiP0.39O3.1C0.1 and ICP-OES P/Ti = 0.35–0.53. We increased the P/Ti ratio using multiple subcycles of TTMSP/H2O up to a maximum P/Ti value of 1.47. All coated fibers were subjected to thermogravimetric analysis in air to test their ability to increase the oxidation resistance of the fibers. As a criterion for the oxidation resistance, we selected the temperature at which a mass loss of 3% with respect to the mass at 400 °C occurs. For uncoated fibers, this 3% mass loss occurs at a temperature3% of 648 °C. All coated fibers showed a moderate upshift of this temperature3%. The maximum temperature3% that we achieved was 711 °C with coatings deposited via the pulse sequence TTMSP/H2O/TTIP/H2O.

Cerium diantimonide (CeSb$_2$) is a layered heavy-fermion Kondo lattice material that hosts complex magnetism and pressure-induced superconductivity. The interpretation of its in-plane anisotropy has remained unsettled due to structural twinning, which superimposes orthogonal magnetic responses. Here we combine controlled crystal growth with magnetization and rotational magnetometry to disentangle the effects of twinning. Nearly untwinned high-quality single crystals reveal the intrinsic in-plane anisotropy: The in-plane easy axis saturates at $M_{\text{easy}}(4~\text{T}) \approx 1.8~μ_{\text{B}}$/Ce, while the in-plane hard axis magnetization is strongly suppressed, nearly linear, and comparable to the out-of-plane response. These results resolve long-standing discrepancies in reported magnetic measurements, in which in-plane metamagnetic transition fields and saturation magnetization varied significantly across previous studies. Growth experiments demonstrate that avoiding the proposed $α$-$β$ structural transition $-$ through Sb-rich flux and slower cooling $-$ systematically reduces twinning. However, powder X-ray diffraction and differential thermal analysis measurements show no clear evidence of a distinct $β$ phase. Our results establish a consistent magnetic phase diagram and provide essential constraints for crystal-electric field models, enabling a clearer understanding of the interplay between anisotropic magnetism and unconventional superconductivity in CeSb$_2$.

ABSTRACT Potassium metal batteries (KMBs) have currently been regarded as one of the most promising energy storage devices for achieving high energy density. However, some inevitable challenges including high reactivity of metallic potassium, dendrite growth, and huge volume expansion impose a heavy burden on potassium metal batteries. Herein, an isocyanate molecule – 4‐(trifluoromethoxy)phenyl isocyanate (TPI) is proposed to tailor the electrolyte solvation structure and interfacial chemistry in KMBs for the first time. The as‐obtained electrolyte exhibits enhanced ionic conductivity, excellent electrode wettability and high exchange current density. Due to the energy levels difference, TPI preferentially accepts or donates electrons and undergoes redox reactions faster, thereby reducing the excessive decomposition of solvent molecules. Moreover, its inherent excellent film‐forming property could form a protective layer at the electrode interface, effectively inhibiting the electrolyte decomposition and the adverse reactions caused by potassium metal. When assembled symmetrical batteries, at a current density of 0.5 mA cm −2 and 0.5 mAh cm −2 , the electrolyte could stably run for more than 1400 h. The PTCDA||K full‐cells could cycle 2000 times with good stability, and the Coulombic efficiency remained at approximately 99.84%. This strategy presents a promising pathway toward achieving performance metrics in KMBs.

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) are a promising energy storage technology, attracting significant interest for their high theoretical energy density, safety, and cost‐effectiveness. However, their commercialization is hindered by persistent interfacial issues at the zinc anode, including dendrite growth, hydrogen evolution, and passivation. This review provides a systematic examination of these challenges, delving into their electrochemical origins and associated anode limitations. We categorize recent optimization strategies into three key domains: electrolyte engineering, anode design, and separator modification. Specific approaches, such as tailoring electrolyte solvation structures, modifying zinc surface and architecture, and functionalizing separators, are detailed to illustrate their effectiveness in stabilizing the anode interface. Finally, we summarize the prevailing constraints and outline future research directions, aiming to inspire the development of innovative materials and strategies for high‐performance AZIBs.