Interfacial Layer Research Articles

Diethylenetriaminepentaacetic Acid-based Conducting Solid Polymer Electrolytes Impede Lithium Dendrites and Impart Antioxidant Capacity in Lithium-Ion Batteries.

In the development of lithium-ion batteries (LIBs), cheaper and safer solid polymer electrolytes are expected to replace combustible organic liquid electrolytes to meet the larger market demand. However, low ionic conductivity and inadequate cycling stability impede their commercial viability. Herein, a novel flexible conducting solid polymer electrolytes (CSPEs) based on polyvinyl alcohol (PVA) and ion-polarized diethylenetriaminepentaacetic acid (P-DETP) is developed for the first time and applied in LIBs. PVA and P-DETP form a compact polymer network through hydrogen bonding, enhancing the thermomechanical stability of CSPE while restricting the migration of larger anions. Furthermore, density functional theory calculations confirm that P-DETP can facilitate the dissociation of Li+-TFSI- via electrostatic attraction, resulting in increased mobility of lithium ions. Additionally, P-DETP contributes to the formation of a stable electrode-electrolyte interface layer, effectively suppressing the growth of lithium dendrites and improving antioxidant capacity. These synergistic effects enable CSPE to exhibit remarkable properties including high ionic conductivity (2.8 × 10-4 S cm-1), elevated electrochemical potential (5.1V), and excellent lithium transference number (0.869). Notably, the P-DETP/LiTFSI CSPE demonstrates stable performance not only in LiFePO4 batteries but also adapts to high-nickel ternary LiNi0.88Co0.06Mn0.06O2 cathode, highlighting its immense potential for application in high energy density LIBs.

Thermal decomposition behavior of ZrO2 barrier layer against Cr/Zr inter-diffusion under high temperature

The Cr/Zr inter-diffusion has been becoming a critical issue for Cr-coated Zr alloys as accident tolerant fuel (ATF) cladding. Here, ZrO2 barrier layers against Cr/Zr inter-diffusion were successfully fabricated between the Cr layer and Zry4 substrate. Thermal decomposition of ZrO2 is confirmed under high temperatures, and ZrO2 is transformed into oxygen-stabilized α-Zr (O), which is effective for mitigating the Cr/Zr inter-diffusion. In-situ transmission electron microscopy (TEM) results indicate that the ZrO2 thermal decomposition process becomes more obvious under 500 ℃. In addition, Cr/α-Zr (O) inter-diffusion leads to the thin Zr(Cr, Fe)2 interface layer due to the high stability of the α-Zr (O) phase.

Multistage rigid and flexible structure-decorated basalt fibers for epoxy resin composites with synergistically enhanced strength and toughness

In this study, we report the construction of a multistage rigid and flexible structure using boron nitride (BN) and MXene (MX, Ti3C2Tx) nanosheets through the conjugation with (3-aminopropyl) triethoxysilane (APTES). The created structure is further utilized to modify basalt fibers (BFs) to obtain BF/epoxy resin (BF/EP) composites via a simple coating process. The rigid two-dimensional materials (2DMs), BN and MX, significantly enhance the roughness of the BF surface, while the silane (APTES) acts as a flexible bridge for linking BFs, BN, and MX. Consequently, the constructed multistage rigid and flexible structure synergistically enhances the strength and toughness of the composite through effective mechanical interlocking, chemical bonding, and multistage energy dissipation. Meanwhile, this complex structure prevents the stress concentration and promotes uniform stress transfer between BFs and EP. This study provides a promising strategy to construct an effective interface layer and achieve high-performance BF/EP composites by introducing 2DMs and a silane linker.

Research and application of joint-constrained inversion of transient electromagnetic multivariate parameter

Due to the phenomena of stratigraphic inclination, complex structure, and lateral discontinuity of resistivity or layer thickness in most of the coal seams, the traditional one-dimensional transient electromagnetic inversion method has limitations in interpretation accuracy. In addition, two- and three-dimensional inversion and artificial intelligence inversion have problems of large computation and large sample size, respectively, which limit their application in small- and medium-sized engineering exploration. To improve the inversion effect, this study proposes a method of joint-constrained inversion of transient electromagnetic multivariate parameters. This method achieves the joint constraint inversion of the transient electromagnetic multi-parameter by making full use of the geological data and a priori information to construct the initial model and adding the constraints such as the resistivity, the thickness, and the layer interface of each layer in the inversion objective function, and at the same time, taking into account the spatial correlation of the stratigraphic structure between the neighboring measurement points, as well as the transverse and vertical constraints between the measurement points along the direction of the survey line and perpendicular to the survey line. First, a series of typical geoelectric models are established and numerically simulated, and the results are compared with those of the traditional inversion method to verify the applicability and effectiveness of the method. Then, the constrained inversion is carried out on the physical simulation and measured data, and the results are in good agreement with the actual geological conditions. The numerical simulation, physical simulation and measured data inversion results consistently prove that this method can effectively reduce the uncertainty of the inversion at the isolated measuring points, improve the spatial continuity of the formation boundary, and better reflect the actual geoelectric characteristics of the formation.

Material removal and damage formation mechanisms induced by periodic indentation during ultrasonic vibration-assisted scratching of SiCf/SiC composites

Fiber-reinforced ceramic matrix composites (CMCs) exhibit high hardness, brittleness, heterogeneity, and anisotropy. This study explores the material removal and damage formation mechanisms during ultrasonic vibration-assisted scratching of SiCf/SiC composites through experimental and micro-finite element simulations. The research reveals that high-frequency periodic indentation-separation of abrasive grain influences stress transfer and crack propagation, which are affected by the interfacial layer and fiber orientation. Crack deflection plays a crucial role in material removal and determines the amplitude of normal scratching force. Stress transfer interference primarily governs damage formation, with more severe damage occurring along the longitudinal and transverse fiber directions due to secondary stress concentration and crack deflection. In contrast, scratching along the perpendicular fiber direction requires higher normal forces due to residual adjacent phase materials, but results in more controlled material removal and less damage. The study provides insights into optimizing the ultrasonic vibration-assisted machining of CMCs to minimize damage.

Functionalized sp2 Carbon-Conjugated Covalent Organic Frameworks for Interfacial Modulation of Inverted Perovskite Solar Cells.

Interfacial modulation utilizing functional materials is proven to be crucial for obtaining high photovoltaic performance in lead halide perovskite solar cells (PSCs). This study investigates, for the first time, the utilization of a pyrene-based sp2 carbon-conjugated covalent organic framework (sp2c-COF) as an interfacial layer in inverted PSCs. Functionalized with cyano (-CN) Lewis base groups, the sp2c-COF exhibits a dual effect, simultaneously passivating both the NiOx and the perovskite layers. Detailed characterization results highlight the role of sp2c-COF in reducing the Ni3+ defect density in NiOx films and forming Lewis acid-base adducts with undercoordinated Pb2+ on the perovskite surfaces, thereby inhibiting interfacial redox reactions and suppressing non-radiative recombination. Moreover, sp2c-COF leads to improved crystallinity of perovskite films. Benefiting from the synergistic effects, sp2c-COF-modified devices delivered a champion efficiency of 17.64%. These findings underscore the potential of sp2c-COF as a functional interface material for PSCs, offering enhanced efficiency and stability. The study contributes to advancing the understanding and application of covalent organic frameworks in photovoltaic technologies.

Achieving photomultiplication in organic-MOF complex via interface and band engineering

This work studies a hybrid broadband photodetector with and without metal–organic framework nanosheets with an inverted structure. It is observed that an inverted structure provides photomultiplication in the devices with both positive and negative biases. This phenomenon is believed to be due to a non-uniform TiO2/active layer interface where the porosity of TiO2 facilitates structural traps, in turn achieving photomultiplication in P3HT: PCBM (1:1) devices. Meanwhile, in photodetectors with an active layer of P3HT:ZnTCPP:PCBM (1:0.5:1), photomultiplication is attributed to interface traps and band alignment due to ZnTCPP nanosheets. The presence of ZnTCPP reduces the dip in EQE at 370–460 and 530–610 nm range, thus improving broadband detection (300–700 nm). Adding ZnTCPP to the devices results in improved rise and fall times. The on–off response is also relatively stable for the devices with ZnTCPP and has high detectivity (1011 Jones). Thus, this study sheds light on the role of a thin interface layer of TiO2 in photomultiplication and improving performance parameters with ZnTCPP nanosheets.

Comparative First-Principles Study of the Y2Ti2O7/Matrix Interface in ODS Alloys

Oxide-dispersion-strengthened (ODS) alloys generally exhibit extraordinary service performance under severe conditions through the formation of ultrafine nano oxides. Y2Ti2O7 has been characterized as the major strengthening oxide in Fe-based ODS alloys. First-principles energetic analyses were performed to investigate the structural, elastic and interface properties of Y2Ti2O7 in either Fe-based or Ni-based ODS alloys. Y2Ti2O7 has comparable elastic constants to bcc-Fe and fcc-Ni and similar elastic deformation compatibility in Y2Ti2O7-strengthened Fe-based and Ni-based ODS alloys is therefore expected. The Ni/oxide interface has generally better thermostability than Fe/oxide across the whole range of the concerned oxygen chemical potential. Further interface bonding and adhesion calculations revealed that Y2Ti2O7 can enhance the bonding strength of Ni/Y2Ti2O7 through d-d orbital interaction between the interfacial YTi layer and Ni layer, while the interface bonding between the Fe layer and YTi layer is weakened compared to the metal matrix. First-principles calculations suggest that Y2Ti2O7 can be a candidate for strengthening nano-oxides in either Fe-based or Ni-based ODS alloys with well-behaved mechanical properties for fourth-generation fission reactors and further experimental validations are encouraged.

The molecular picture of the local environment in a stable model coacervate.

Complex coacervates play essential roles in various biological processes and applications. Although substantial progress has been made in understanding the molecular interactions driving complex coacervation, the mechanisms stabilizing coacervates against coalescence remain experimentally challenging and not fully elucidated. We recently showed that polydiallyldimethylammonium chloride (PDDA) and adenosine triphosphate (ATP) coacervates stabilize upon their transferto deionized (DI) water. Here, we perform molecular dynamics simulations of PDDA-ATP coacervates in supernatant and DI water, to understand the ion dynamics and structure within stable coacervates. We found that transferring the coacervates to DI water results in an immediate ejection of a significant fraction of small ions (Na+ and Cl-) from the surface of the coacervates to DI water. We also observed a notable reduction in the mobility of thesecounterions incoacervates whenin DI water, both in the cluster-forming and slab simulations, together with a lowered displacement of PDDA and ATP. These results suggest that the initial ejection of the ions from the coacervates in DI water may induce an interfacial skin layer formation, inhibiting further mobility of ionsin the skin layer.

Electrical Double Layer and In Situ Polymerization SEI Enables High Reversible Zinc Metal Anode.

Aqueous zinc-ion batteries (AZIBs) stand out among new energy storage devices due to their excellent safety and environmental friendliness. However, the formation of dendrites and side reactions on the zinc metal anode during cycling have become the major obstacles to their commercialization. This study innovatively selected Sodium 4-vinylbenzenesulfonate (VBS) as a multifunctional electrolyte additive to address the issues. The dissociated VBS- anions can not only significantly alter the hydrogen bond network structure of H2O in the electrolyte, but also preferentially adsorb on the surface of the zinc anode before H2O molecules, which will result in the development of organic anion-rich interface and alterations to the electrical double layer (EDL) structure. Furthermore, the ─C═C─ structure in VBS leads to the formation of an in situ polymerized organic anion solid electrolyte interface (SEI) layer that adheres to the surface of the zinc anode. The mechanisms work together to significantly improve the performance of Zn//Zn symmetric batteries, achieving a cycle life of over 1800h at 1mA cm-2 and 1 mAh cm-2. The introduction of VBS also enhances the cycling performance and capacity of Zn//δ-MnO2 full cells. This study provides a low-cost solution for the development of AZIBs.

Engineering the solvent-anion interactions of LiTFSI-based dual-salt electrolytes to sustain high-performance NCM622 cathodes

Electrolytes play a vital role in determining the performances of lithium-ion batteries (LIBs), especially the high-voltage LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode in LiTFSI-based electrolytes. Herein, we report a high-capacity and stable NCM622 cathode that can be realized in LiTFSI-based (named T) carbonate electrolytes by tuning the intermolecular interactions using the added LiDFOB (named D). In the 1 M dual-salt electrolyte, the cathode failure and Al corrosion are suppressed in the 4.5 V-NCM622||Li batteries, because a uniform interfacial layer and weaker Li+-solvent interactions are built to inhibit the parasitic reactions. As a result, the capacity retention reaches 94.68% after 200 cycles and the 10 C-rate capacity is about 160 mA h g-1 in the 1 M T + D dual-salt electrolyte. Unlike the commonly used electrolyte, the FEC additive increases the de-solvation barrier and disturbs the cycle stability in (T + D) dual-salt systems. Density functional theory (DFT) calculation and nuclear magnetic resonance (NMR) spectra reveal that the additive FEC changes the solvent-solvent and solvent-anion interactions in the presence of T + D, which weakens the electrolyte-cathode compatibility. This work indicates that regulating the solvation structure and interfacial chemistry from solvent-solvent/anion interactions is promising for designing high-performance LIBs by using dual‐salt electrolytes.

Electrolyte Solvation Engineering Stabilizing Anode-Free Sodium Metal Battery With 4.0V-Class Layered Oxide Cathode.

Anode-free sodium metal batteries (AFSMBs) are regarded as the "ceiling" for current sodium-based batteries. However, their practical application is hindered by the unstable electrolyte and interfacial chemistry at the high-voltage cathode and anode-free side, especially under extreme temperature conditions. Here, an advanced electrolyte design strategy based on electrolyte solvation engineering is presented, which shapes a weakly solvating anion-stabilized (WSAS) electrolyte by balancing the interaction between the Na+-solvent and Na+-anion. The special interaction constructs rich contact ion pairs (CIPs) /aggregates (AGGs) clusters at the electrode/electrolyte interface during the dynamic solvation process which facilitates the formation of a uniform and stable interfacial layer, enabling highly stable cycling of 4.0V-class layered oxide cathode from -40°C to 60°C and excellent reversibility of Na plating/stripping with an ultrahigh average CE of 99.89%. Ultimately, industrial multi-layer anode-free pouch cells using the WSAS electrolyte achieve 80% capacity remaining after 50 cycles and even deliver 74.3% capacity at -30°C. This work takes a pivotal step for the further development of high-energy-density Na batteries.

Quantitative Measurement of Cooperative Binding in Partially Dissociated Water Dimers at the Hematite "R-Cut" Surface.

Water-solid interfaces pervade the natural environment and modern technology. On some surfaces, water-water interactions induce the formation of partially dissociated interfacial layers; understanding why is important to model processes in catalysis or mineralogy. The complexity of the partially dissociated structures often makes it difficult to probe them quantitatively. Here, we utilize normal incidence X-ray standing waves (NIXSW) to study the structure of partially dissociated water dimers (H2O-OH) at the α-Fe2O3(012) surface (also called the (11̅02) or "R-cut" surface): a system simple enough to be tractable yet complex enough to capture the essential physics. We find the H2O and terminal OH groups to be the same height above the surface within experimental error (1.45 ± 0.04 and 1.47 ± 0.02 Å, respectively), in line with DFT-based calculations that predict comparable Fe-O bond lengths for both water and OH species. This result is understood in the context of cooperative binding, where the formation of the H-bond between adsorbed H2O and OH induces the H2O to bind more strongly and the OH to bind more weakly compared to when these species are isolated on the surface. The surface OH formed by the liberated proton is found to be in plane with a bulk truncated (012) surface (-0.01 ± 0.02 Å). DFT calculations based on various functionals correctly model the cooperative effect but overestimate the water-surface interaction.

Aerogel‐Driven Interface Rapid Self‐Gelation Enables Highly Stable Zn Anode

AbstractThe practical application of Zn metal anodes is currently hindered by uncontrolled dendritic growth and water‐induced parasitic reactions that are closely related to the solvation structure and interfacial transport kinetics of Zn2+. Herein, a facile interface self‐gelation strategy is proposed to stabilize Zn anode by introducing ‐OH‐rich silica aerogel (HSA) on Zn anode surface. The unique interconnected network structure and strong hydrophilia of HSA made the aqueous electrolyte near Zn anode gel rapidly and spontaneously, resulting in the formation of a water‐poor gel interface layer. The interface layer can effectively accelerate the desolvation process and reduce water molecule activity near anode surface through hydrogen bonding interaction, thus achieving rapid Zn migration kinetics and alleviating side reactions. In addition, the well‐defined aerogel nanochannels can provide a fast Zn2+ migration path and homogenize Zn2+ flux, enabling rapid and uniform Zn deposition. As a result, the HSA‐modified Zn (HSA@Zn) anode exhibits excellent long‐term cycling stability (over 6000 h at 4 mA cm−2), and the feasibility for practical application of this HSA@Zn anode is further demonstrate in full cells. The aerogel‐driven interface self‐gelation strategy propose in this work provides new insights into the design of advanced Zn anode for aqueous zinc‐ion batteries.

Influence of interfacial roughness on slot-die coatings for scaling-up high-performance perovskite solar cells

Slot-die coating (SDC) technology is a potential approach to mass produce large-area, high-performance perovskite solar cells (PSCs) at low cost. However, when the interface in contact with the perovskite ink has low wettability, the SDC cannot form a uniform pinhole-free perovskite film, which reduces the performance of the PSC. To address this issue, in this study, the wettability of the hole transport layer (HTL) interface was investigated in depth by analyzing the variation of wettability with process and its correlation with the roughness of the HTL interface. As a result, it was found that SDC could increase the roughness of the HTL interface to improve wettability and form a uniform high-quality perovskite layer without pinholes, and furthermore, SDC-based NiOx/Me-4PACz HTL suppressed energy losses at the HTL/perovskite interface. In addition, a unit cell achieved 19.17% of efficiency with long-term stability and lab cell-sized modules showed up to 17.42%.

Superior role of V2O5 and yttrium interface layers in enhancing MIS radical photodiode performance

In this study, Cu/n-Si Schottky diodes with V2O5–Y insulating interface layer were designed for the fabrication of metal/insulator/semiconductor (MIS) structures. The effects of different Y–V2O5 interface layers placed between metals and semiconductors on the critical electrical parameters of Schottky diodes were examined. Electrical parameters of the prepared sample such as barrier height (ΦB), ideality factor (n), photosensitivity (Ps), photosensitivity (R), quantum efficiency (QE) and detectivity (D∗) were obtained from the expression. Characteristics of I–V The modification in these parameters can be attributed to the use of Schottky diodes as intermediate layers. Additionally, n, ΦB values were calculated using the thermionic emission process and the photodiode parameters Ps, R, QE and D∗ the results were compared with each other. Experiments have shown that the Schottky structure with V2O5–Y interlayer leads to higher values of Ps = 799.70 % and under the light condition of 6 wt% of Y lower value n = 2.01. This provides evidence of the improved performance of MIS models.

Dynamic 3D hydrogen-bond network in siloxene-water system enables efficient moisture-enabled electricity generation

Utilizing ubiquitous moisture as an energy source for moisture-enabled electric generator (MEG) has emerged as a significant technological frontier. The migration process of protons at the water/solid interface is crucial for understanding the mechanism of moisture-to-electricity conversion and efficient energy harvesting. However, the lack of clarity on this scientific question has hindered the substantive development of MEG. Here, a novel dynamic three-dimensional (3D) hydrogen-bond network between the interface of siloxene layers was designed through water molecule intercalation. The spatial bridging effect of this dynamic 3D hydrogen-bond network, formed on the siloxene layers, enhances the load transfer capability of the siloxene-water system, thereby randomizing the direction of proton hopping. Experimental and theoretical calculations demonstrate that the dynamic 3D hydrogen-bond network constructed within and between the siloxene layers facilitates rapid proton conduction. Kinetic simulations further confirm that the strength of the hydrogen-bond network accelerates proton transport rate. The current density of siloxene under high humidity increases significantly, reaching 22.37 µA cm−2, which is 122 times that under low humidity, as well as the open-circuit voltage reaches 0.73 V. This work contributes to understanding the microscopic mechanisms behind efficient moisture-enabled electricity and provides a fresh perspective for enhancing MEG performance.

Molecule-Level Multiscale Design of Nonflammable Gel Polymer Electrolyte to Build Stable SEI/CEI for Lithium Metal Battery

HighlightsNonflammable gel polymer electrolyte (SGPE) is developed by in situ polymerizing trifluoroethyl methacrylate (TFMA) monomers with flame-retardant triethyl phosphate (TEP) solvents and LiTFSI–LiDFOB dual lithium salts.Molecular polarity interaction between TEP and PTFMA mitigates interfacial reactions and changes the solvation of Li+.SGPE forms stable inorganic-rich solid electrolyte interface/cathode electrolyte interface layer, exhibiting well compatibility with Li anode and LiCoO2-type high-voltage cathode.

Numerical Modeling of Water Transport in a Microporous Layer-Coated Porous Transport Layer for a Polymer Electrolyte Membrane Water Electrolyzer with an Interdigitated Flow Field for Internal Gas-Liquid Separation

A novel design for interdigitated flow fields in polymer electrolyte membrane electrolyzers has been developed for both ground and space applications. This design separates oxygen and liquid water internally, eliminating the need for water circulators to remove bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer (MPL) of the anode porous transport layer facilitates internal separation of oxygen gas and pressurized liquid water. A finite element model (COMSOL Multiphysics) simulates water transport in the MPL, while electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model takes into account the oxygen bubble coverage of the cathode, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-cathode layer interface. The vapor from liquid water in the MPL is modeled to mix with oxygen for diffusion. A volumetric water evaporation rate as a linear function of liquid water saturation in the MPL is assumed, where the rate constant is estimated from vapor permeation tests.

The Effects of Contact By the Catalyst Layer and the Gas Diffusion Layer Interface on the Performance of a PEFC with Marimo-like Carbon

When assembling a proton exchange membrane fuel cell (PEMFC), a clamping pressure is applied to all the components. The catalyst layer (CL) and gas diffusion layer (GDL) are compressed to the gasket thickness by the clamping during assembly. This compression increases the conductivity of the protons and electrons while reduces the size of the pores, which are the removal channels for the generated water and the diffusion channels for the fuel and air gases. We evaluated the effect of the CL compression prepared with the Marimo-like carbon (MC) regarding the I-V performance. The MC is a higher order structure of carbon fibers. The maximum power density was the highest (237 mW cm-2) at the 22% compression ratio. The excessive compression was suggested to have a higher effect on blocking the diffusion channels of the fuel and air gases than on improving the conductivity.