This work investigates the surface functionalization of quartz fibres via direct carbon nanotube (CNT) synthesis as a route to tailored multiscale and multifunctional interfaces in advanced composite systems. Thermal and plasma-enhanced chemical vapour deposition (PE-CVD) are systematically compared to elucidate the relationship between synthesis conditions, CNT morphology, fibre mechanical integrity, and surface physico-chemical and functional properties. While conventional thermal CVD at 620–640 °C induces a severe degradation of the original fibre tensile strength (≈74%), PE-CVD enables the growth of a dense layer of radially aligned CNTs at lower temperatures (520–540 °C), thereby mitigating the thermal contribution to fibre strength degradation, although additional strength loss still occurs during catalyst-assisted CNT synthesis. Microscopic (SEM, TEM, AFM) and spectroscopic (Raman, EDS, EELS) analyses demonstrate that plasma assistance promotes CNT growth despite incomplete catalyst nanoparticle formation at low annealing temperatures, yielding CNTs with smaller diameters (≈12 nm), hollow cores, and reduced tortuosity. Wettability, surface-energy and single fibre fragmentation analyses demonstrate that CNT decoration enhances fibre–epoxy interfacial adhesion, resulting in an approximately 31% increase in interfacial shear strength through improved physico-chemical affinity and mechanical interlocking. Finally, CNT-modified quartz fibres demonstrate electrochemical activity for hydrogen peroxide generation, highlighting their potential as reinforcements in multifunctional composite materials for environmental remediation applications.

Abstract Solid-state batteries employing lithium-rich manganese oxide positive electrodes are a highly promising candidate for next-generation high-energy-density energy storage systems. However, the practical deployment of lithium-rich manganese oxide positive electrodes is hindered by several critical challenges, including poor initial-cycle reversibility, rapid capacity decay, structural collapse due to oxygen release, and interfacial instability at high potentials. Here, we introduce a thiourea-derived surface modification strategy for lithium-rich manganese oxide positive electrodes, which significantly enhances the electrochemical performance of solid-state batteries (SSBs). The modified lithium-rich manganese oxide positive electrodes exhibit an initial discharge capacity of 220.2 mAh g −1 , an initial Coulombic efficiency of 84.83 %, and capacity retention of 97 % after 600 cycles at 1 C under 4.6 V (vs. Li + /Li). The improved cycling performance is shown to be attributed to a dual modification of lithium-rich manganese oxide particles, i.e., the application of sub-nm-thick S-rich coating layer and formation of a spinel-like structure in the surface near proximity, which prevents oxygen-related degradation and accelerates Li + transport, respectively. These findings present a scalable surface modification strategy that potentially addresses key limitations of lithium-rich manganese oxide-based SSBs, paving the way for the development of stable, high-energy-density batteries.

Silicon is a high-capacity anode material, yet its scalable production from sustainable precursors requires low-temperature and controllable synthesis routes. Diatom-derived SiO2 provides an abundant biogenic feedstock, but its conversion to silicon by magnesiothermic reduction (MgTR), typically conducted at 600-900 degrees C, is limited by the highly exothermic nature of the reaction, which induces local overheating, promotes side-phase formation, and often results in incomplete SiO2 reduction. Here, we elucidate the reaction pathway of AlCl3-assisted MgTR as a strategy to decrease synthesis temperature and improve reduction efficiency. By correlating the heating ramp rate, isothermal hold time, and salt-to-silica ratio with phase evolution and the crystalline silicon fraction, we identify the parameters governing oxygen abstraction and Si formation. Time-resolved in situ synchrotron X-ray diffraction provides direct insight into the reaction mechanism, revealing the early formation of metallic Al, the transient formation of MgAl2Cl8 as an intermediate, and the subsequent crystallization of Si concurrent with the consumption of metallic Al, thereby suggesting that Al acts as an effective reducing agent. Silicon formation proceeds within a chloride-rich molten phase and is achieved at temperatures as low as 250-300 degrees C. The crystalline silicon fraction is primarily dictated by heating conditions and AlCl3 content, with optimized parameters maximizing the Si fraction while suppressing inactive byproducts. Electrochemical evaluation of the graphite-SiOx electrode blends demonstrates enhanced reversible capacity relative to graphite together with moderate cycling stability, confirming the electrochemical activity of the synthesized material. Overall, this work unveils the mechanistic framework of AlCl3-assisted MgTR and provides synthesis guidelines for the low-temperature conversion of diatom biosilica into silicon-based anode materials.

Silicon-graphite (SiGr) blended negative electrodes have reached the Li-ion battery (LIB) market and outperform pure graphite in specific capacity. However, commercial implementations still rely on low Si contents, whereas industry targets approximate to 30 wt% Si and higher, where accelerated degradation and complex Si-Gr coupling limit the usable Si fraction and hinder the transition to Si-rich electrodes. This study resolves the dynamic interplay between Si and Gr (de)lithiation reactions in a 30:70 Si:Gr blended electrode over the first five cycles by combining operando synchrotron X-ray diffraction with TEM observations. Crystalline silicon (c-Si) undergoes approximate to 95% amorphization in the first cycle, leaving minor crystalline remnants in core-shell domains. A broad first-cycle reduction feature in the voltage-capacity profile at 0.35-0.70 V vs Li/Li+ accompanies this structural transition and the substantial irreversible capacity loss. From the second cycle onward, Gr lithiation degree (x in LixC6) declines from 0.84 to 0.33, evidencing a shifting in Si-Gr utilization balance. A benchmark under identical conditions against a partially amorphized Si-rich electrode retaining approximate to 25 % c-Si after cycling and exhibiting a more stable Gr lithiation degree demonstrates that the extent of early Si amorphization governs both the Si-Gr balance and overall electrode behavior. By quantitatively tracking amorphization with high temporal resolution and comparing extensive versus partial transformation pathways, this work establishes a time-resolved structural framework for Si-rich blended anodes, underscoring early-cycle amorphization control as a practical design lever.

Tetragonal tungsten bronzes are normally uniaxial ferroelectrics making crystallographic texture pivotal for optimization of electrical properties. SrxBa1-xNb2O6 (SBN), x=0.4, 0.5 and 0.6, thin films with out-of-plane (001) or in-plane (310) oriented polarization were deposited by aqueous chemical solution deposition on SrTiO3 (STO)(100) substrates. A texture degree of >90% was achieved for (001) oriented SBN films on SrO terminated STO, while the (310) oriented films on TiO2 terminated STO possessed a degree of texture >50%. The films were in compression compared to bulk due to epitaxial strain, thermal strain, and a reduced lattice parameter of the film due to Ti-doping, all related to the substrate used. The Curie temperature of selected (001) oriented films showed the expected decrease with increasing Sr content, and additional decrease attributed to Ti-doping. A piezo response was measured in (001) oriented films by in situ application of an electrical field during X-ray diffraction measurements.

Aluminium alloys are used in component manufacturing due to their favourable properties like high strength-toweight ratio, good formability, and corrosion resistance. However, since welding processes are often an integral part in multi-component assemblies, the thermal stability is an important criterion when selecting Al alloys. Among possible candidates, Al-Mg-Si-Cu alloys have demonstrated a remarkable good thermal stability. This is primarily attributed to the formation of ordered and partly disordered precipitates like the L phase during precipitation hardening. However, despite these alloys' promising properties, their performance during rapid heating and cooling remains relatively unexplored. This study systematically investigates the microstructure evolution within the heat-affected zone (HAZ) of a welded peak-age Al-Mg-Si-Cu alloy on the advancing side of the joint, and assesses how these changes relate to measured hardness and tensile properties using electron microscopy and mechanical testing. Scanning precession electron diffraction is used to identify and spatially map the precipitates. The results reveal that almost all precipitate types dissolve in the HAZ where the peak temperature reaches approximately 285-375 degrees C. At higher peak temperature, approaching 450 +/- 25 degrees C, only the L phase and precipitates typically observed in the alloy's over-aged condition remain. The potential of exploiting the L phase's thermal stability to narrow the HAZ width through thermomechanical processing is briefly discussed toward the end of the paper.

The structural material discovery for high-temperature irradiation applications such as advanced nuclear reactors is challenging due to the extreme service conditions. To address the challenge, the current work explored an innovative approach involving a nano oxide dispersion strengthened (ODS) medium-entropy alloy with nanosized grains. We demonstrate the efficacy of the approach in ODS-NiCoFe alloy. The ODS-NiCoFe exhibited a twofold enhancement in hardness compared to softer single-crystal NiCoFe. The post-irradiation (Ni2+ ions, 580°C) investigations demonstrated a relative irradiation hardening (~25%) resistance for ODS-NiCoFe, better than the well-known ODS steels. Additionally, the study exhibited the stability of nanosized precipitates and grains; thus, the alloy facilitated numerous nanoprecipitate-matrix interfaces and grain boundaries to annihilate irradiation-induced defects. The alloy contained dislocation loops as major defect structures and showed no observable presence of significant voids. The void swelling resistance is due to the absorption of mobile stacking fault tetrahedra at the grain boundaries and Shockley dislocation dominant chains. Thus, the findings reveal the high-temperature radiation resistance of the novel ODS-NiCoFe and present a state-of-the-art strategy for designing structural materials.

For the past decade, silicon (Si) as a material for negative electrodes of Li-ion batteries has been considered among the most promising candidates for replacing commonly used graphite. However, Si-based electrodes suffer from severe degradation, which depends on the type of Si materials used. Generally, the degradation of Si is mainly viewed in terms of particle fracturing during lithiation accompanied by constant growth of the solid electrolyte interphase (SEI). At the same time, the reversed process, delithiation, has received little attention. The present work demonstrates the morphological changes of the Si components of electrodes occurring during electrochemical cycling through electron microscopy analyses. These changes are rationalized through the migration of Si, resulting in the formation of Si dendrites embedded in SEI. With the assistance of ReaxFF modeling, we demonstrate that the delithiation predominantly drives this process. The present study reveals that fracturing of Si particles is not the only cause for degradation, as the Si surfaces dramatically change after prolonged cycling, resulting in the formation of Si dendrites.

Layered oxides exhibit high ionic mobility and chemical flexibility, attracting interest as cathode materials for lithium-ion batteries and the pairing of hydrogen production and carbon capture. Recently, layered oxides emerged as highly tunable semiconductors. For example, by introducing anti-Frenkel defects, the electronic hopping conductance in hexagonal manganites was increased locally by orders of magnitude. Here, we demonstrate local acceptor and donor doping in Er(Mn,Ti)O$_3$, facilitated by the splitting of such anti-Frenkel defects under applied d.c. voltage. By combining density functional theory calculations, scanning probe microscopy, atom probe tomography, and scanning transmission electron microscopy, we show that the oxygen defects readily move through the layered crystal structure, leading to nano-sized interstitial-rich (p-type) and vacancy-rich (n-type) regions. The resulting pattern is comparable to dipolar npn-junctions and stable on the timescale of days. Our findings reveal the possibility of temporarily functionalizing oxide semiconductors at the nanoscale, giving additional opportunities for the field of oxide electronics and the development of transient electronics in general.

The current research utilized a unique material design of nanostructured medium-entropy alloys with numerous defect sinks, offering great potential to withstand extreme conditions in advanced nuclear reactors. Hence, this work examined oxide dispersion strengthened (ODS)-NiCoFeCr alloy with nanosized grains after Ni+2 irradiation at 580 °C up to a peak damage of 101 displacements per atom. The alloy showed insignificant hardening and no detectable void formation following irradiation. Also, oxide nanoprecipitates and grains exhibited a limited growth of ~2 and ~5 nm, respectively, with irradiation. The volume-averaged dislocation length density remained on the order of ~1014 m−2, and the mean dislocation length showed a slight increase from 89 to 97 nm, with irradiation. A lower level of radiation-induced segregation was observed at the grain boundaries; however, the extent of RIS depended on the misorientation angles, with a maximum at 45.7° among the grain boundaries analyzed.

Silicon-Graphite (SiGr) blended anodes represent a promising approach for enhancing the energy density of commercial Li-ion batteries (LIBs). However, the ≈300% volume change of the silicon component during lithiation and delithiation induces significant mechanical stress, leading to particle cracking and pulverization that compromise electrode stability. This study presents the first evidence of controlled Si lithiation in Si-rich blended anodes, where a crystalline silicon (c-Si) core remains unreacted while the outer shell undergoes complete amorphization. Operando synchrotron X-ray diffraction analysis of SiGr anodes over five consecutive cycles reveals a reversible lithiation of c-Si, which was not previously reported. Complementary transmission electron microscopy (TEM) analysis of focused ion beam (FIB)-prepared lamellae from cycled electrodes confirms the formation of an amorphous shell and preservation of the c-Si core. These findings validate the feasibility of a partial lithiation strategy for SiGr anodes and provide unprecedented insights for the design of mechanically stable electrodes. Additionally, the interpretation of lithiation/delithiation differential capacity plots is discussed in light of the observed structural evolution, offering both fundamental and practical advancements for the development of robust SiGr anodes for high-energy-density LIBs.

Highly sensitive and energy-efficient gas sensors are essential for real-time environmental monitoring and air quality assessment. In this work, we present an optically programmable gas sensor based on WSe2/hBN heterostructure transistors for NOx detection. The hBN interfacial layer enhances device performance by reducing charge trapping and improving transport, enabling the WSe2/hBN configuration to achieve a higher sensing response and faster recovery than WSe2/SiO2 devices. To understand the sensing mechanism, in situ Kelvin probe force microscopy (KPFM) was used, revealing that NOx adsorption at the metal/semiconductor interface modulates the Schottky barrier height (SBH), which governs charge transport and gas sensitivity. Furthermore, we demonstrate that UV-induced charge modulation allows dynamic control of the sensor response, offering a tunable and reversible method for optimizing gas detection. This study highlights the potential of heterostructure engineering and optoelectronic modulation in developing next-generation, low-power, smart gas sensors for environmental monitoring applications.

Silica (SiO2) anodes are promising candidates for enhancing the energy density of next-generation Li-ion batteries, offering a compelling combination of high storage capacity, stable cycling performance, low cost, and sustainability. This performance stems from SiO2 unique lithiation mechanism, which involves its conversion to electroactive silicon (Si) and electrochemically inactive species. However, widespread adoption of SiO2 anodes is hindered by their slow initial lithiation. To address this, research has focused on developing electrochemical "activation protocols" that involve prolonged low-potential holding steps to promote SiO2 conversion. Despite these efforts, the complex and multi-pathway nature of SiO2 lithiation process remains poorly understood, impeding the rational design of effective activation strategies. By introducing a multi-probe characterization approach, this study reveals that, contrary to the previously proposed reaction mechanism of SiO2 anodes, the lithiation process initiates at low potentials with the direct formation of Li4SiO4 and LixSi. Electrochemical activation potential was found to significantly influence the degree of conversion, with 10 mV identified as the optimal cut-off potential for maximizing SiO2 utilization. These findings provide key enablers to unlock the full potential of SiO2 anodes for battery technology.

The conventional electrolytes for Li-ion batteries are based on the LiPF6 salt and carbonate solvents. Due to challenges with the stability, alternative salts are sought, and lithium bis(fluorosulfonyl)imide (LiFSI) is an interesting candidate. In this work, we investigate the performance of concentrated electrolytes based on LiFSI (range 1-10 M) and carbonate solvents, in combination with low-cost, micron-sized silicon anodes. LiFSI has an excellent solubility, and by use of concentrated electrolytes, corrosion of the aluminium current collector on the cathode side can be avoided, which is otherwise a challenge. The 5 M LiFSI electrolyte (molar salt to solvent ratio of 1:2.5) shows a similar ohmic resistance and rate performance as the 1 M LiFSI electrolyte. The solid electrolyte interphase formed in 5 M LiFSI is thin and dominated by inorganic compounds, in particular LiF. For long-term galvanostatic cycling with a lower cut-off potential of 50 mV, the 1 M LiFSI electrolyte shows the best stability. However, by limiting the lithiation, and thus the expansion of the silicon by increasing the cut-off voltage to 120 mV, the cycling performance is similar for all electrolytes and electrodes deliver >1000 mAh/g for more than 300 cycles.

Cold bonding between dissimilar metals and alloys offers several benefits, such as the absence of soft heat-affected zones and thick intermetallic layers with properties that differ from those of the base metals. At room temperature, thermally driven diffusion processes are negligible, but we demonstrate here that mechanically strong bonds are still feasible through high plastic deformation and high strain rates. If the strain rate is high and the temperature is kept low to avoid significant annihilation of vacancies, mechanically strong bonds involving intermetallic compound formation can still form through vacancy-driven diffusion across the contact interface. In the present investigation, two different experimental setups were employed to demonstrate strong bonding between copper and aluminium at room temperature, using phenomenological equations for excess vacancy formation and diffusion to highlight the underlying bonding mechanisms involved. Transmission electron microscopy is used to verify the bonding mechanisms.

Layered oxides exhibit high ionic mobility and chemical flexibility, attracting interest as cathode materials for lithium-ion batteries and the pairing of hydrogen production and carbon capture. Recently, layered oxides emerged as highly tunable semiconductors. For example, by introducing anti-Frenkel defects, the electronic hopping conductance in hexagonal manganites is increased locally by orders of magnitude. Here, local acceptor and donor doping in Er(Mn,Ti)O3 is demonstrated, facilitated by the controlled splitting of anti-Frenkel defects under applied d.c. voltage. By combining density functional theory calculations, scanning probe microscopy, atom probe tomography, and scanning transmission electron microscopy, it is shown that the oxygen defects can readily be moved through the layered crystal structure, leading to nano-sized interstitial-rich (p-type) and vacancy-rich (n-type) regions. The resulting pattern is comparable to dipolar npn-junctions and stable on the timescale of days. These findings reveal the possibility of temporarily functionalizing oxide semiconductors at the nanoscale, giving additional opportunities for the field of oxide electronics and the development of transient electronics in general.

Microscale cold welding is an efficient method for achieving high-quality joints, particularly in electronic components, as its low-temperature process preserves the mechanical and electrical properties of the base metals. However, the limited fundamental understanding of successful bonding mechanisms for dissimilar metal joining has significantly restricted its industrial adoption. This is especially true at the microscale, where heat-assisted methods are still generally preferred. Therefore, this work presents a test bed procedure for cold welding of dissimilar metals at the microscale. A Focused Ion Beam (FIB) -scanning electron microscope was employed to design, monitor and characterise the technique, allowing complete control over the welding parameters, such as speed, geometry, and superficial oxides. Successful bonding was achieved without preliminary surface preparation by pushing a tapered copper wire into a pre-made hole in a soft aluminium alloy. The copper wire diameter was larger than that of the hole, promoting shear stresses and plastic deformation. Cross-sectional analysis of joints revealed severe grain refinement near the bonded interface. Elemental mapping highlighted that shear forces removed most contaminants mechanically as soon as contact began. Bonding defects originated from microscopic residuals of oxides or contaminants from the FIB, while a uniform interface was observed in their absence. A four-probe setup for in-situ electrical resistance measurement across the Al-Cu interface was tested, and it was indirectly used to testify the bond quality. Transmission electron microscopy investigations revealed that interdiffusion occurred across the joint interface, forming a thin intermetallic Al-Cu layer, even in the presence of a nanoscopic fragmented oxygen layer.

Integrated logic circuits using atomically thin, two‐dimensional (2D) materials offer several potential advantages compared to established silicon technologies such as increased transistor density, circuit complexity, and lower energy dissipation leading to scaling benefits. In this article, a novel approach to achieve tunable doping in 2D semiconductors is explored to achieve complementary transistors and logic integration. By selectively transferring WSe2 onto hBN and SiO2 substrates, complementary transistor behavior (n‐ and p‐type) was achieved using a UV light source and electrostatic activation. Furthermore, advanced characterization techniques, including high‐resolution transmission electron microscopy (HRTEM) and Kelvin probe force microscopy (KPFM), provided insights into the chemical composition and surface potential changes after UV writing. Finally, a logic inverter was successfully implemented using selectively photo‐induced doped WSe2 transistors, showcasing the potential for practical logic applications. This innovative method opens new avenues for designing energy‐efficient and reconfigurable 2D semiconductor circuits, addressing key challenges in modern electronics.