Polymer composite electrolytes must exhibit multifunctional stability, maintaining mechanical, thermal, and electrochemical properties, while also achieving high ionic conductivity. A composite polymer electrolyte (CPE) incorporates a highly conductive, flexible polymer matrix combined with ceramic loading to enhance ionic conductivity and specific capacity in LiFePO4 (LFP)/Li solid-state battery (SSB) cells. Characterizing the effect of ceramic loading has on multifunctional stability provides insights into CPE design and optimization.In this work, we examined a series of CPEs, synthesized by blending polyethylene oxide (PEO), polyethylene glycol dimethyl ether (PEGDME) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) at 10, 20, and 30 wt.%. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis reveal that LiTFSI, PEGDME, and LLZTO each The electrochemical impedance spectroscopy (EIS) results show a marked reduction in both interfacial and bulk resistances with increasing LLZTO content, leading to an improvement in ionic conductivity. In particular, the 30 wt.% LLZTO CPE exhibited a conductivity of 2.25×10−4 S/cm at 40°C, representing a 70.23% improvement over the 20 wt.% LLZTO CPE, which exhibited a conductivity of 1.38×10−4 S/cm at 40°C. The baseline PEO-PEGDGME-LiTFSI polymer electrolyte, without any LLZTO, exhibited an ionic conductivity 0.97x10-4 S/cm at 40°C. Long-term cycling performance in Li/CPE/Li symmetric cells demonstrated operation for up to 1,000 cycles without failure for 0, 10 and 20 wt.% LLZTO CPE. For instance, the 20 wt.% LLZTO CPE maintained a total resistance less than 1 kΩ after 1000 cycles, measured at room temperature. However, the 30 wt.% LLZTO CPE showed signs of short-circuiting after 550 cycles. Its severe LLZTO agglomeration and the presence of uncoated LLZTO at the solid electrolyte interface, as confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), may promote Li dendrite growth along the grain boundaries of LLZTO.Our results suggest that the 20 wt.% LLZTO CPE offers optimal long-term mechanical, thermal and electrochemical stability while maintaining low total resistance, compared to other compositions tested, delivering a specific capacity of 150.87 mAh/g at C/5 charging rate in a LFP/Li SSB cell. The effect of LLZTO CPE compositions on capacity retention and Coulombic efficiency of SSB cells and key design parameters for stable CPEs will be discussed, with an emphasis on enhancing the Li/CPE interfacial stability, thereby improving the performance of SSBs.

Growing application of magnetic thin films and inductor chips for analog circuits in voltage regulators, mobile phones, MEMS and defense sector technologies rise need for new alloys and structures with low energy losses during electromagnetic induction process. Miniaturization of the new thin film inductor devices requires that these alloys and structures have the highest possible magnetic moment and resistivity to achieve high specific inductance and minimum permeability loses related to Eddy currents.We present work on development of electrodeposition process for 2.2-2.4 T CoFeX alloys and CoFeX/X laminated structures from single solution chemistry. They show no permeability decrease over the wide frequency range up to 0.5 GHz. This is achieved by alloy bulk resistivity control adding a resistivity controlling element in the alloy X (X=O, P, C) and introducing a resistive barrier layer with electrochemical lamination to control the alloy laminate thickness to be below the alloy skin depth. Therefore, achieving the structures with complete suppression of Eddy currents for inductor devices with lossless induction process. The schematics of the deposition process is shown in Figure 1A. The one-laminate deposition includes a cycle consisting of two stages: (a)-CoFeX-alloy deposition (t1, j1) and (b)-electro-polymerization stage (PPY resistive barrier, t2, E=-0.75 V). The process is repeated arbitrary number of times to create laminated structure with desired thickness. The representative data are shown in Figure 1B. The permeability and quality spectra from cavity induction measurements illustrate advantage of laminated structures over the bulk thin film alloy. Figure 1. (A) Schematics of the laminate synthesis via electrodeposition and electro- polymerization steps. (B) Permeability and Q spectra from cavity measurements for thin film CoFeX alloy and CoFeX/X laminated structure. Insets show surface morphology of electrodeposits. Figure 1

Copper (Cu) interconnects are an increasingly important bottleneck in integrated circuits due to energy consumption and latency caused by the notable increase in Cu resistivity as dimensions decrease, primarily due to electron scattering at surfaces. Here, we showcase the potential of two classes of metals for scaled interconnects 1) directional conductors that have low bulk resistivity and anisotropic structures that mitigate electron surface scattering, and 2) topological semimetals that utilize topologically protected surface states to suppress electron scattering. We will highlight thin films of PtCoO2 of various thicknesses, synthesized by molecular beam epitaxy (MBE) coupled with a post-deposition annealing process and the superior quality of PtCoO2 films is demonstrated by multiple characterization techniques. We will also discuss CoSi and GaPd, topological semimetals that exhibit reduced resistivity with decreasing wire dimensions, including a novel single-crystal synthesis technique. The thickness-dependent resistivity curves illustrate that PtCoO2 significantly outperforms effective Cu (Cu with TaN barriers) and Ru in resistivity below 20.0 nm with a more than 6x reduction compared to effective Cu below 6.0 nm, having a value of only 6.32 μΩ∙cm at 3.3 nm. CoSi exhibits a marked reduction in resistivity from its bulk values, but is still not competitive with Cu.

Research on high-frequency electrochemical impedance spectroscopy (HF-EIS), focusing on frequency band exceeding 1 MHz, has attracted much attention in recent years. For example, Nakajima et al. reported a spectral change in HF-EIS during the first ten charge and discharge cycles of lithium-ion batteries1. In another study, Ishigaki et al. developed a method to detect metallic lithium deposited on the electrode surface by using the skin effect characteristics of HF-EIS2.However, several issues need to be solved. First, it is necessary to use an experimental apparatus which are not typically used in the field of electrochemistry such as impedance analyzers and network analyzers, since the upper frequency limit of most commercially available potentio/galvanostats with frequency response analyzer is about 1 MHz. Additionally, due to the specifications of most apparatus, coupling capacitors are required to be inserted into the circuit to block the DC current when measuring samples which has an electromotive force. Furthermore, it is important to ensure that the inductive reactance of the wires is sufficiently lower in order to discuss the bulk resistance of the samples.In this study, we developed fixtures for HF-EIS measurements of 2032-type coin cells using a commercially available impedance analyzer and discussed measurement-related challenges.References Nakajima, N. Yamamoto, and Y. Tanaka, Proceeding of the 65th Battery Symposium in Japan, (2022), 3C17. Ishigaki, K. Ishikawa, T. Usuki, H. Kondo, S. Komagata, and T. Sasaki, Nature Communications 14, (2023), 7275.

ABSTRACT Flexible pressure sensors hold transformative potential in personalized healthcare and motion‐aware electronics. However, constrained by a single conduction mechanism, current sensors still face significant challenges in simultaneously achieving high sensitivity, wide range, and robust stability. Herein, a gradient doping hierarchical microstructure flexible piezoresistive sensor with multi‐path conduction mechanisms is developed. The synergistic combination of micro‐engineered surfaces and spatially graded doping enables significant resistance variation at low pressures, yielding a high sensitivity of 101.1 kPa −1 . Multi‐path conduction mechanisms (including surface resistance, interlayer electrode resistance, interlayer contact resistance, interlayer tunneling resistance, and bulk resistance) enable tunable resistivity under high loads, extending the sensing range from 0.32 Pa to 3.6 MPa (a span of seven orders of magnitude). Moreover, the integrated full‐carbon nanotubes/polydimethylsiloxane design shows high stability, durability (over 5000 cycles), and fast response/recovery time (10/58 ms). As a proof of concept, the sensor's application for broad‐range biomechanical monitoring has been validated, spanning from subtle pulse waveform detection to high‐intensity plantar pressure monitoring. This work advances next‐generation wearables for simultaneous high‐fidelity physiological tracking and extreme‐force kinematic analysis.

Silver-based electrically conductive adhesives (ECAs) are widely used in the connection, conduction, and packaging of electronic components. However, commercial ECAs typically contain more than 90 wt % Ag fillers, creating an urgent demand for low-Ag-content alternatives that maintain excellent performance. To address this issue, Ag with 3D structures has significant low-content and structural advantages in efficiently constructing 3D conductive networks in the ECAs system. Herein, three types of Ag-based fractal flowers with 3D branched structures (Ag FW-I, Ag FW-II, and Ag FW-III) were successfully synthesized using a novel, facile, and efficient chemical reduction method. The Ag FW-II particles served as the primary conductive framework, while Ag FW-I and Ag FW-III acted as auxiliary fillers, bridging gaps and connecting isolated regions. When the Ag FW-I, Ag FW-II, and Ag FW-III contents were optimized to 17.5, 50, and 12.5 wt %, respectively, the resulting ternary ECAs can deliver the lowest bulk resistivity of 1.15 × 10-4 Ω·cm and a high adhesion strength of 12.88 MPa. These Ag FWs-based ECAs demonstrate the best balance of conductivity and adhesion strength, offering a promising solution for the electronic packaging industry.

ABSTRACT Biopolymer electrolytes have emerged as promising materials for energy storage and electrochemical applications due to their eco‐friendliness, flexibility, and ionic conductivity. This study investigates xanthan gum (XG) complexed with sodium chloride (NaCl) as a sustainable, flexible solid biopolymer electrolyte (SBEs) for energy storage applications. SBE films were fabricated via solution casting and characterized using X‐ray diffraction (XRD), impedance spectroscopy, and dielectric analysis. XRD confirmed the amorphous nature of the XG: NaCl system, promoting ion transport. Impedance spectroscopy revealed a significant decrease in bulk resistance with NaCl doping, leading to enhanced ionic conductivity, reaching a maximum of 8.83 × 10 −6 S/cm at 30°C for 80XG: 20NaCl system. Dielectric analysis revealed significantly low‐frequency polarization, indicating excellent charge storage capabilities. These findings demonstrate that XG: NaCl SBEs are a highly promising, cost‐efficient solution for next‐generation electrochemical energy storage devices.

Sodium rare earth silicate is regarded as a novel and promising solid electrolyte (SE) for solid-state sodium metal batteries (SSSMBs) because the merits of high ionic conductivity, low sintering temperature, and excellent chemical stability. However, impurity phases and voids induced by sintering always cause weak ion conduction and large electron conduction at grain boundaries, resulting in the growth of Na dendrites. Herein, a facile grain boundary modification strategy is conducted by introducing a second phase of Na1.5Y2.5F9 into the grain boundaries of Na5YSi4O12. The Na1.5Y2.5F9 phase can not only effectively impede the migration of electrons and reduce the bulk resistance and grain boundary resistance, but also improve the densification and mechanical strength of SE. Consequently, the Na/Na symmetric cell delivers a large critical current density of 0.7mA cm-2 and an ultra-long cycle life of 9000h at 0.1mA cm-2 and 0.05 mAh cm-2 without dendrite formation. Moreover, the assembled full cell achieves excellent cycling stability at 1 C for 750 cycles with a capacity retention of 70.2% and enhanced rate capability of 113.5 mAh g-1 at 2 C. This work lays a foundation to develop high-performance sodium rare earth silicate-based SE for ultra-durable SSSMBs.

Abstract Conductive ink development is vital for advancing flexible, lightweight, and cost-effective electronic devices. Flexography printing, known for its high-speed and roll-to-roll capabilities, offers a scalable method for producing such electronic components. However, achieving optimal printability and electrical conductivity in nickel (Ni) nanoparticle inks remains a significant challenge, primarily due to the complex interplay between binder selection, ink formulation and substrate interaction. This study aims to enhance both the printability and electrical performance of Ni nanoparticle inks printed on paper by systematically optimizing the formulation by the binder choice and its content in the ink. Spherical Ni nanoparticles (~ 40 nm) were combined with a range of binders to evaluate their influence on print quality and electrical performance. Post-printing processes, including photonic curing and calendering, were employed to enhance film uniformity and electrical performance, resulting in a notable 99% decrease in resistivity. Notably, the formulation utilized a carboxylated styrene-butadiene binder that achieved a bulk resistivity as low as 3 × 10-3 Ω·cm. The findings underscore the importance of binder chemistry in developing Ni nanoparticle inks with superior printability and electrical performance. The results show that Ni inks are well-suited for a range of printed electronics applications where moderate conductivity meets performance requirements, such as RFID antennas, touch interfaces, flexible circuit interconnects, temperature detectors, and EMI shielding for flexible electronics.

Laser‐enhanced metal contact technology has recently emerged as an effective approach to reducing contact recombination in silicon solar cells, particularly in tunneling oxide passivating contacts cells with a front boron‐doped emitter and rear phosphorus‐doped polysilicon based passivating contact. This technique enables superior front‐side surface passivation and open‐circuit voltages comparable to those of silicon heterojunction counterparts. In this study, we conducted a comprehensive simulation‐based analysis comparing the devices with laser‐enhanced contacts (LASER) to conventional devices with selective emitters, using experimentally extracted bulk defect parameters across a range of bulk resistivities. Additionally, we evaluated the low‐light illumination response of the devices and conducted energy yield simulations under various solar conditions. High‐resistivity wafers consistently enhance efficiency when bulk defect levels are low but may degrade performance when defect densities are high, especially in devices with laser‐enhanced contacts. Under low‐light conditions, the benefits of high‐resistivity wafers are further diminished in the presence of significant bulk defects, resulting in reduced energy yields in regions with poor or variable solar resources, despite gains in areas with abundant sunlight. The findings provide valuable insights into the impacts of bulk resistivity, bulk defect density, and illumination intensity on the device performance as well as energy yield.

Abstract The effect of a synthesized waterproofing and accelerating admixture on the properties of Ordinary Portland Cement (OPC) mortar cube was investigated, focusing on compressive strength, setting time, bulk density, apparent porosity, and water absorption. The study employed advanced characterization techniques such as FT-IR, XRF, XRD, TG/DTG, and DSC to analyze the chemical and structural changes within the cement matrix. It was demonstrated that the admixture significantly enhances compressive strength, with a 25% increase observed within the first three days of curing. Additionally, the admixture reduces setting time and apparent porosity while increasing bulk density and resistance to water absorption. The most effective concentration was found to be 2%, which provided optimal improvements in mechanical properties and durability. The results show a 25% increase in compressive strength after 3 days, a 35% increase after 7 days, and a 37% increase after 28 days with an optimized combined 2% admixture. XRD confirmed enhanced C–S–H formation and reduced portlandite at the optimal 2% admixture. TG/DTG and DSC results indicated increased bound water and accelerated hydration. These findings correlate with higher compressive strength, reduced porosity, and increased bulk density, confirming the admixture’s role in refining the microstructure and improving cement mortar performance.

Microstructure, mechanical properties and oxidation resistance of bulk W-B-Fe-Cr for fusion shielding

As a critical component in high-voltage cable accessories, ethylene-propylene-diene monomer (EPDM) reinforced insulation faces severe issues of surface discharge and bulk breakdown at the insulation interface. To enhance the electrical resistance of EPDM bulk and insulation interfaces, the 4-allyloxy-2-hydroxybenzophenone was employed as a voltage stabilizer to modify EPDM. A systematic study was conducted on the influence of the voltage stabilizer on the DC breakdown strength of EPDM, the anti-migration properties of the voltage stabilizer, and its effect on the surface breakdown voltage of EPDM. Additionally, pressure and surface breakdown test setups were designed. The results indicate that the DC breakdown strength of EPDM decreases with increasing external pressure, and this decline is more pronounced in EPDM modified with the voltage stabilizer. Surface breakdown experiments demonstrate that the voltage stabilizer has a positive effect on improving the surface breakdown voltage of EPDM, with a more significant enhancement observed at the EPDM/XLPE bilayer dielectric interface. Surface potential tests reveal that the grafted voltage stabilizer introduces numerous shallow traps, inhibiting surface charge accumulation and thereby increasing the surface breakdown voltage.

This work involved the development of polymer blends consisting of polymethacrylate (PMMA)/polyvinyl acetate (PVAc)/tetrabutylammonium iodide (TBAI)/milled multiwalled carbon nanotubes (MWCNTs), PMMA/PVAc/TBAI/x wt % milled MWCNTs employing the casting methodology as promising blends for use in numerous optoelectronics applications. The impact of milled MWCNTs on the structure and morphology of the resultant blends was considered. Except for the blend with x = 0, all the other samples exhibited a significant rise in energy density values relative to the pure sample. The conductive mechanisms in numerous samples were also studied. The activation energies of diverse blends were determined. A non-Debye-type ionic relaxation process was observed in all blends. According to the amount of MWCNTs doping, the bulk resistivity and ionic conductivity fluctuated, going up or down. A rise in temperature led to an enhancement in the ionic conductivity for all blends. A reduction in DC conductivity was found in the doped samples relative to the unfilled sample, and this decrease became more pronounced with the higher quantities of MWCNTs.

Efficient fabrication of flexible electrodes based on cellulose nanofiber-reinforced polyaniline and nanobiochar for Mg-ion battery.

This study aims to enhance the dielectric and electrical properties of PVC/PMMA polymer blends by incorporating graphene nanoplatelets (GNPs) for potential use in energy storage devices. Nanocomposites were prepared via the solution casting method and characterized using various analytical techniques such as XRD, HR-TEM, FTIR, UV-Vis spectroscopy, dielectric measurements, AC conductivity, and impedance spectroscopy. X-ray diffraction (XRD) analysis revealed the emergence of a sharp crystalline peak at 2θ = 26.48°, corresponding to the (002) plane of GNPs, while the overall crystallinity of the polymer nanocomposites decreased due to disrupted polymer chain packing. HR-TEM imaging confirmed the layered morphology of GNPs, emphasizing 2D nanostructure with high surface area. FTIR spectroscopy indicated strong interfacial interactions, including π-π stacking and hydrogen bonding. UV-Vis. absorption spectra exhibited a redshift and increased intensity with higher GNP content, correlating with band gap narrowing due to charge carrier delocalization. Dielectric measurements demonstrated a remarkable increase in the dielectric constant (ε′), reaching 1.6 × 103 at 10 Hz for the 0.25 wt.% GNP composite, attributed to Maxwell-Wagner-Sillars polarization. AC conductivity analysis revealed a transition from insulating to conductive behavior with increasing GNP concentration, supported by impedance spectroscopy, which showed a reduction in bulk resistance. These findings highlight the potential of GNP-reinforced PVC/PMMA composites for capacitive energy storage applications.

This study investigates the significant factors on weld quality in the resistance spot welding of quench and partitioning advanced high-strength steel. Attention is laid emphasis on nugget formation and growth, weldability range (lobe curve), nugget size and shape (macrostructural features), coating effects, mechanical properties, and fracture behavior of resistance spot welds. As zinc-coated steel sheets are widely applied in body-in-white in automotive industry, coating’s effect on weld quality is particularly significant. The research establishes correlations of nugget macrostructure, coating effects, and the following mechanical properties and fracture characteristics of the welds. Key conclusions recognize that Zn coating significantly alters the nugget formation mechanism by reducing the electrical contact resistance. Compared with uncoated samples, Zn-coated steels require a larger welding current for nugget formation because the major heat generation transforms from contact resistance to bulk resistance within the steel sheet. This reduction in contact resistance heating leads to larger nuggets for the same weld conditions. The uncoated samples show greater hardness of fusion zone and tensile-shear strength than coated samples, recording peak load-bearing capacities of 28 kN and 24 kN for medium heat input conditions, respectively. The critical welding current to transition into pullout failure mode was 9.5 kA for uncoated samples and 9.0 kA for coated samples. These findings highlight the complex interplay among coating presence, process conditions, and nugget shape attributes, all of which are crucial for predicting the mechanical performance and failure mode of resistance spot welds in Zn-coated QP980 steel.

This study explores the synergistic role of glycerol in enhancing the ionic conductivity and dielectric properties of a novel methylcellulose (MC)–chitosan (CS) polymer composite doped with sorbitol and TiO2 nanoparticles (NPs), complexed with NaSCN salt. Glycerol was incorporated at varying concentrations (8–40 wt.%) to investigate its influence on polymer flexibility, ion mobility, and charge transport mechanisms. The films were synthesized via solution casting and characterized using FTIR, XRD, and UV-Vis spectroscopy. Electrochemical impedance spectroscopy (EIS) was utilized to analyze ionic conductivity, while dielectric performance was assessed via frequency-dependent dielectric studies. Results indicate that increasing glycerol content significantly reduced bulk resistance (Rb), from 10 kΩ (at 8% glycerol) to 343 Ω (at 40% glycerol), accompanied by an impressive rise in ionic conductivity from 0.414 µS/cm to 16.333 µS/cm a 39.45-fold enhancement. Dielectric relaxation analysis showed a shift in tan δ peaks toward higher frequencies and reduced relaxation times, suggesting enhanced segmental motion and faster ion dynamics. However, excessive glycerol slightly hindered performance due to possible ion clustering and increased viscosity. The optimal glycerol incorporation enhances polymer flexibility, ion dissociation, and charge carrier mobility, establishing the CS:MC:Sorbitol:TiO2–NaSCN–glycerol system as a promising candidate for flexible solid-state batteries and supercapacitors.

In resistance spot welding (RSW), the total electrical resistance (dynamic resistance) as the sum of bulk and contact resistance is a key variable. Both of these respective resistances influence the welding result, but the exact ratio to the total resistance of a real existing sheet is not known. Due to the high scatter in the RSW of aluminum alloys compared to steel, it is of interest to be able to explicitly determine the individual resistance components in order to gain a better understanding of the relationship between the initial state and the lower reproducibility of aluminum welding in the future. So far, only the total resistance and the bulk resistance could be determined experimentally. Due to the different sample shapes, it was not possible to consistently determine the contact resistance from the measurements. In order to realize this, a method was developed that contains the following innovations with the aid of simulation: determination of the absolute bulk resistance at room temperature (RT), determination of the absolute contact resistance at RT and determination of the ratio of bulk and contact resistance. This method makes it possible to compare the resistances of the bulk material and the surface in the initial state quantitatively. This now allows the comparison of batches regarding the surface resistance, especially for welding processes. For the aluminum sheets (EN AW-5182-O, EN AW-6014-T4) investigated, the method showed that the contact resistance dominates and the bulk resistance is less than 20%. These data can also be used to make predictions about the weldability of the alloy using artificial intelligence (AI). If experimental data are available, the method can also be applied to higher temperatures.

In this study, a novel multi‐core–dual‐shell strategy is employed to synthesize 3D porous microspheres. These microspheres consist of Si armed with CoSi2 nanoplates multi‐cores encapsulated within dual protective shells of metallic‐Co nanocrystals embedded nitrogen‐doped graphitic carbon (NGC) and polydopamine‐derived carbon (PDA‐C), denoted as Si@CoSi2‐Co/NGC@PDA‐C, through a multistep synthesis process involving facile spray pyrolysis and post‐heat‐treatment. The Si as an active material is surrounded by an inactive buffer material of CoSi2 with intrinsic low bulk resistivity and high chemical stability, enhancing the electrical interconnectivity and mechanical integrity of the nanostructure. The metallic‐Co embedded porous NGC shell facilitates rapid electron transfer by providing primary transport pathways due to its high conductivity, while improving structural robustness by partially restraining the volume expansion of Si. Finally, an additional PDA‐derived C protective shell provides secondary transport pathways while mitigating volume expansion, preventing complete detachment from the current collector or pulverization. Correspondingly, the Si@CoSi2‐Co/NGC@PDA‐C anode exhibits considerable rate capability (up to 10 A g−1) and remarkable cycling stability (88% capacity retention after 600 cycles; average capacity loss of 0.02% per cycle at 1.0 A g−1). Moreover, full‐cells paired with a Li(Ni0.8Co0.1Mn0.1)O2 cathode are evaluated to confirm the practical viability of the nanostructures.