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Morphology control is a key design parameter for sodium-ion layered oxide cathodes, yet achieving uniform precursors with balanced stoichiometry is more challenging than in lithium-ion systems due to the broader range of transition-metal chemistries involved. These complexities highlight the need for systematic comparisons of coprecipitation routes tailored to sodium-ion compositions. Here, we examine how ammonia- and citrate-based coprecipitation methods shape the morphology and composition of equimolar Ni–Fe–Mn hydroxide and oxyhydroxide precursors. We investigate how pH, ligand concentration, and temperature jointly influence precipitation onset, particle shape, and metal incorporation. In the ammonia system, precipitation proceeds readily between pH 10.5–11.5, with pH ≈ 11.0 yielding the most uniform morphology and target Ni:Fe:Mn ≈ 1:1:1 stoichiometry. Higher ammonia levels improve morphology but above ∼1.0 M begin to delay Ni incorporation and introduce phase separation. In contrast, the citrate system shows delayed precipitation (threshold pH ≈ 11.8) but forms dense granular microspheres with narrow size distributions across 0.1–0.6 M citrate, with Fe enrichment emerging at higher ligand concentrations. X-ray diffraction revealsβ-Ni(OH)₂-type hydroxides for ammonia-derived precursors andδ-FeOOH-type oxyhydroxides for citrate-derived ones. Together, these results provide practical guidance for tailoring precursor morphology and composition in Fe- and Mn-rich sodium-ion cathode materials. 

The first in-situ X-ray diffraction (XRD) study of the evolution of the crystallite size and dislocation density in phases during plastic strain-induced phase transformation (PT) is performed utilizing α-ω PT in strongly pre-deformed commercially pure Zr as an important example. Rough diamond anvils (rough-DA) are introduced to intensify all occurring processes during heterogeneous compression of Zr in a diamond anvil cell (DAC). The main rule is found that during α-ω PT, the crystallite size and dislocation density in ω-Zr depend solely on the volume fraction of ω-Zr and are independent of pressure, plastic strain tensor, its path, and initial nanostructure. Crystallite size in ω-Zr increases from 10 to 60 nm during the PT, while dislocation density reduces from 1.83 ×1015/m^2 to 0.6 ×1015/m^2. Rough-DA produce a steady nanostructure in α-Zr before PT with smaller crystallite size and larger dislocation density than smooth-DA, leading to a reduction of the minimum pressure for α-ω PT to a record value 0.67 GPa, 9 times smaller than under hydrostatic loading and 5.1 times lower than the phase equilibrium pressure. In addition to strain, the kinetics of strain-induced PT unexpectedly depends on time. Also, strain-controlled part of kinetics is zero order, in contrast to the first-order kinetics with smooth-DA. The obtained results open a new window for understanding the mutual effects of nanostructure evolution and PT during severe plastic flow in various technological and natural processes. They may bring up economic strategies of producing nanocomposites and single-phase nanostructured materials with optimal properties. 

Time-domain thermoreflectance (TDTR) has been a standard technique for measuring thermal conductivity (κ) for more than 3 decades, yet its reliance on femtosecond lasers and metal transducers has limited its broader adoption in the materials community. Recent attempts to eliminate the metal layer have achieved partial success but have been hampered by dominant reflectance from photoexcited carriers, arising from the continued use of femtosecond pump and 800-nm probe pulses. Here, we introduce a nanosecond transducer-less TDTR (tl-TDTR) method that overcomes this challenge. Using ~80-ns pump pulses and a 450-nm continuous-wave probe, we suppress carrier-induced negative transients, yielding positive signals characteristic of pure thermoreflectance. Thermal conductivity is extracted via heat transport simulations and direct time-domain curve fitting. The method is validated on benchmark semiconductors (Si, Ge, InP) and cross-checked on Si and diamond using an Al-film transducer. Applied to cubic boron arsenide crystals, the technique reveals room-temperature κ exceeding 2,000 W/m·K—comparable to single-crystal diamond—and confirmed by traditional TDTR on the same samples. Raman, photoluminescence (PL), and PL lifetime measurements indicate high crystal quality. Sub-10-ns lifetimes remain shorter than expected for an indirect bandgap semiconductor, suggesting headroom for further κ improvement. The observed ~1/T²temperature dependence indicates dominant 4-phonon scattering. Nanosecond tl-TDTR thus provides a rapid, nondestructive route to assess semiconductor thermal conductivity.