Hybrid Layer Research Articles

Contemporary Concepts of Adhesive Cementation of Glass-Fiber Posts: A Narrative Review.

(1) Background: Cementation of glass fiber posts to root canals has been associated with various failures, especially debonding. This narrative review aims to present the contemporary concepts concerning the adhesive cementation of glass fiber post and to discuss the optimal management of these factors. (2) Methods: Electronic search was performed in MEDLINE/Pub Med and Google Scholar using selected keywords examining the parameters post length, surface treatment of glass fiber posts, post space preparation and dentin pretreatment, resin cement selection, adhesive systems and hybrid layer formation, and clinical techniques. (3) Results: The search led to the selection of 44 articles. Epoxy resin-based endodontic sealers are recommended and the use of temporary cement in the root canal should be avoided. The minimum length of a glass fiber post adhesively cemented to a root canal is 5 mm. Irrigating the root canals with chlorhexidine, MTAD, or EDTA (alone or in combination with NaOCl) after post space preparation seems to enhance the bond strength. Silane application on the surface of the post seems to be beneficial. Concerning resin cements and adhesive systems, the results were rather inconclusive. Finally, resin cement should be applied inside the root canal with an elongation tip and photoactivation should be delayed. (4) Conclusions: Contemporary concepts of adhesive cementation of glass fiber posts can indeed improve the bond between glass fiber posts, resin cement, and root canal dentin, however, evidence coming from long-term randomized prospective clinical trials is needed in order to obtain safer conclusions.

New Monomer Capable of Dual Chemical Binding with Dentin to Improve Bonding Durability.

The water-rich nature of the dentin bonding microenvironment, coupled with the stresses on the bonding interface, contributes to the hydrolytic degradation of the hybrid layer, resulting in a decline in bonding durability and, ultimately, restoration failure. Currently, the 3-step etch-and-rinse technique remains the gold standard for dentin bonding, and the bonding mechanism mainly involves a physical interaction with little chemical bonding. In this study, we have developed a siloxane-modified polyurethane monomer (SPU) with acrylate and siloxane modifications that chemically binds to both collagen and hydroxyapatite in dentin. Formulated as a bisphenol A-glycidyl methacrylate alternative, the SPU monomer-based adhesive was designed to improve dentin bonding quality and durability. Attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, and hydroxyproline release assays were performed on SPU-treated collagen, hydroxyapatite, and acid-etched dentin slices to dentin. The physicochemical properties of the configured SPU adhesives were profiled for polymerization behavior, water contact angle, and tensile strain and strength. The bonding effectiveness was assessed through micro-tensile strength, nano-leakage tests conducted on the bonded samples before and after thermal cycle aging. Finally, we further conducted in vivo and in vitro experiments to assess the biocompatibility of adhesives. The results showed that the siloxane groups of SPU monomer could covalently bind to dentin collagen and hydroxyapatite. The incorporation of SPU in the adhesive led to a significant increase in adhesive polymerization (P < 0.05) and tensile strain at break up to 134.11%. Furthermore, the SPU adhesive significantly improved dentin bond strength (P < 0.05), reduced interfacial nano-leakage (P < 0.05), and displayed good biocompatibility. In conclusion, the application of SPU, which achieves dual chemical bonding with dentin, can improve the quality of the hybrid layer, buffer the interfacial stresses, enhance the interfacial resistance to hydrolysis, and provide a feasible strategy to extend the service life of adhesive restorations.

Boosting magnetic loss and impedance matching based on laminated structure for balancing low-/high-frequency broadband microwave absorption

Balancing low-/high-frequency broadband absorption is significantly essential for realizing ultra-wideband microwave absorption but mains challenging. In this work, laminated dielectric@magnetic FePO4/CrPO4@FeSiCr flakes have been created using facile vertical ball milling technique and subsequent phosphate passivation process. The flaky morphology provides the strong magnetic loss ability for boosting a lower-frequency microwave absorption. The dielectric@magnetic structure contributes good impedance matching and sufficient double loss mechanism for ensuring a wideband higher-frequency microwave absorption. The unique laminated structure is benefit for multi-scattering and reflection, which can balance the low-/high-frequency broadband absorption. With 6 h ball milling, FePO4/CrPO4 hybrid layer covers FeSiCr flakes deliver effective absorption bandwidth (EAB) of 1.6 GHz covering 2.4–4.0 GHz (S-band) with 3.2 mm, EAB of 3.52 GHz covering 4.40–7.92 GHz (C-band) with 1.9 mm and EAB of 8.24 GHz covering 9.36–17.6 GHz (X+Ku band) with 1.1 mm. Generally, an easy pathway is provided in this work for developing ultra-wide microwave absorbers that balance low-/high- frequencies.

A Highly Sensitive Plasmonic Graphene-Based Structure for Deoxyribonucleic Acid Detection

In this study, a Kretschmann structure with a hybrid layer of graphene–WS2 is designed to develop a sensitive biosensor for deoxyribonucleic acid detection. The biosensor incorporates a 45 nm gold layer as the active layer and a thin film of chrome as the adhesive layer. Through the optimization of the graphene and WS2 layers, combined with the implementation of a silicon layer, we can enhance the nano-sensor’s sensitivity. The thin silicon layer acts as a protective barrier for the metal, while also increasing the volume of interaction. Consequently, by adjusting the thickness of the active metal and adding a silicon layer, we achieve higher sensitivity and a lower full width at half maximum, leading to sensitivity of 333.33°/RIU. The designed structure is analyzed using numerical techniques and the finite difference time domain method, allowing us to obtain the optical characteristics of the surface plasmon polariton sensor. Various parameters are calculated and evaluated to determine the optimal conditions for the sensor. Furthermore, the total size of the sensor is 2.228 µm2.

Enhancing the stability of Li2NiO2 cathode additive with polyborosiloxane coating for high-energy lithium-ion batteries

Li2NiO2 has garnered considerable interest as a Li-excess cathode additive for high-energy lithium-ion batteries (LIBs), attributed to its high irreversible capacity during the initial cycle and an operating voltage comparable with that of commercial cathode materials. However, its integration into practical applications is limited by its suboptimal cycling performance owing to moisture instability and gas evolution. To surmount these obstacles, we developed a hybrid surface coating strategy employing polyborosiloxane (PBS)—a structural derivative of polydimethylsiloxane (PDMS) synthesized with boric acid (H3BO3)—applied to a Li2NiO2 cathode additive. The bi-functional of the PBS layer enhances moisture resistance and ionic conductivity on the Li2NiO2 surface. A hydrophobic, elastic PDMS matrix offers conformal coverage, forestalling adverse moisture-induced side reactions. The introduction of H3BO3 into the PDMS matrix on the Li2NiO2 surface fosters the formation of Li–B–O bonds, thus augmenting the ionic conductivity of the coating. This innovative approach with the PBS layer significantly diminishes the interfacial resistance and improves the cycling performance of Li2NiO2 while preventing substantial structural degradation. In a full-cell configuration incorporating a PBS-coated Li2NiO2 cathode additive with a LiNi0.8Co0.1Mn0.1O2 cathode and a SiOx/Graphite anode, the enhanced energy density and sustained stable cycling performance exceed 300 cycles. This hybrid layer can aid in producing longer-lasting, more efficient LIBs that can fulfill the requirements for use in high-energy storage solutions.

Matrix metalloproteinase inhibitors in restorative dentistry.

Matrix metalloproteinases (MMPs) have been identified as agents that disintegrate the collagen structures of dental hybrid layers, resulting in reduced restorative bond strength. Multiple MMP inhibitors (MMPIs) are known to counteract this degenerative mechanism, thereby preserving bond strength and promoting the longevity of resin-based restorations. Additionally, literature suggests that certain MMPI materials possess antimicrobial/anticariogenic properties, potentially reducing the risk of secondary caries development. Therefore, this review article aims to narrate on the integration of matrix metalloproteinase inhibitors into adhesive systems and their impact on bond strength.

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth’s marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Water/ethanol and water/acetone proanthocyanidin solutions enhance the mechanical stability and sealing ability of resin-dentin bonds produced by the cross-linked dry bonding technique

ObjectivesTo evaluate the influence of solvents on the mechanical stability and dentin sealing ability of adhesive interfaces produced on dry dentin after collagen biomodification with a proanthocyanidin-rich grape seed extract (GSE). MethodsFlat dentin surfaces (N = 120) were initially divided into 10 groups. After phosphoric acid etching for 15s, the etched dentin was treated with: water (control), 5 % ethanol, 90 % ethanol, 5 % acetone, 90 % acetone, and the same groups added with 5 % GSE. The treatments were kept on the etched dentin for 60s. Then, the teeth of each treatment were further divided into two groups. Thus, after rinsing, the dentin was kept moist (wet bonding) or air-dried for 60 s (dry bonding). A water-free two-step etch-and-rinse adhesive system (Optibond S, Kerr) was applied, and composite blocks were built up. The teeth were tested for bond strength (μTBS) immediately or after 12 months of aging. Considering the μTBS results, additional teeth were prepared for qualitative analysis of nanoleakage (NL; SEM) and hybrid layer permeability (CLSM). The μTBS data were analyzed with three-way RM ANOVA and Tukey (α = 0.05). ResultsThe immediate μTBS did not differ among treatments for wet dentin. For dry dentin, GSE in 5 % ethanol or acetone presented the highest μTBS values, the latter similar to wet control. After 12 months, μTBS of GSE in 5 % ethanol or acetone were comparable to the immediate results for wet and dry techniques. These reduced NL and improved dentin sealing for both dentin wetness conditions like the immediate wet control. ConclusionsThe application of 5 % GSE to etched dentin, either in 5 % ethanol or 5 % acetone, resulted in enhanced mechanical stability and dentin sealing of interfaces produced on dry dentin. SignificanceDentin biomodification with proanthocyanidin in the presence of ethanol or acetone makes bonding procedures less sensitive by eliminating the need to keep dentin wet and increasing the quality and stability of hybrid layers produced on dry etched dentin.

Effects of structural parameters on radial crashworthiness of 3D braided hybrid tubes with Janus structure

Hybrid fiber reinforced plastic (HFRP) composites have been widely used in various fields, but delamination is a fatal damage mode in laminated hybrid tubes. In the current paper, carbon fibers/Kevlar fibers hybrid tubes with Janus structure were fabricated by three-dimensional (3D) tubular braiding technique. The radial crushing performances of 3D braided Janus hybrid tubes were analyzed while hybrid layer ratio and yarn type were both considered. With the increase of hybrid layer ratio from 1:3 to 2:2 to 3:1, the specific energy absorption (SEA) increased 149 % and 21.39 % for specimens with carbon fibers placed on the skin region, and that decreased 12.46 % and 10.66 % for samples with Kevlar fibers arranged on the skin region. Furthermore, samples with Kevlar fibers arranged on the skin region presented excellent radial crashworthiness. The current work could be helpful for the design, fabrication and application of HFRP tubes.

Transmission/reflection mode switchable ultra-broadband terahertz vanadium dioxide (VO2) metasurface filter for electromagnetic shielding application

In this paper, we present an ultra-broadband terahertz (THz) vanadium dioxides (VO2) metasurface (MS) filter with switchable transmission/reflection modes for electromagnetic (EM) shielding application. The MS filter is composed of a three-layer periodic composite structure, consisting of two VO2/metallic hybrid layers and a metal mesh layer, which are separated by two benzocyclobutene (BCB) dielectric layers. The transmission property of the proposed MS filter is illustrated by the numerical simulation based on the finite element method (FEM) and equivalent circuit model (ECM). When VO2 is in insulating state, the designed composite structure acts as a filter with ultra-broadband bandpass response (BPR), exhibiting that the transmission coefficient exceeds 90 % from 1.07 THz to 3.78 THz, with a relative bandwidth of 112 %. However, owing to thermal excitation, the VO2 converts from an insulating to a metallic state, the composite structure can be functioned as a filter with ultra-broadband bandstop response (BSR) with a transmission coefficient less than 6 % spanning the range of 0.1 to 4.5 THz. In addition, the physical mechanism of the designed MS filter is investigated utilizing impedance matching theory and electric field distribution analysis. Furthermore, the MS filter has good polarization insensitivity and angular stability. Finally, we quantify the shielding effectiveness (SE) in two states and evaluate the impact structural parameters of the unit-cell, resulting in a SE of more than 25 dB in reflection mode across the entire operating frequency range. Our proposed MS filter with its exquisite performance has the potential to be widely applied in EM shielding.

Bond Strength of Resin Cement Following Biomimetic Remineralization: An in vitro Study

Objectives This research assessed the efficacy of self-assembling peptide P11-4 (Curodont protect) in promoting biomimetic remineralization of dentin, thereby stabilizing the hybrid layer and enhancing the long-lasting of the resin-dentin bond. Methods Five premolar teeth were longitudinally sectioned to assess dentin microhardness before and after demineralization, as well as after the application of P11-4 (Curodont protect). For the microtensile test, ten premolar teeth were sectioned perpendicular to their long axes. The teeth were assigned to different groups. Following acid etching and rinsing, samples in control group I received no pretreatment, while the prepared dentin surface of group II was treated with 0.1 mL of P11-4 before the placement of the adhesive restoration. All specimens were stored in distilled water at 37 ± 2 °C for 24 hours and then underwent thermocycling. The microtensile test was measured, and the type of bond failure was evaluated. The obtained information, expressed in megapascals, was analyzed using a one-way analysis of variance (ANOVA), followed by Tukey’s multiple post hoc test. Results There was a statistically significant difference in hardness values after demineralization, followed by a significant increase in hardness after the application of P11-4 (Curodont protect) (p &lt; 0.001, effect size = 0.985). No statistically significant difference was found in the microtensile bond strength between the two groups (p = 0.384, effect size = 0.582). Adhesive-type failure was more commonly observed. Conclusion The use of self-assembling peptide P11-4 (Curodont protect) on dentin resulted in higher microhardness than the control group without adversely affecting resin cement bond strength.

Sealing of pulp chamber dentin in endodontics: Influence of bond strategy and time-point application

Context: Seal the dentin of the pulp chamber during endodontic treatment to avoid interfering with the restorative treatment performed afterward. Aims: The aim was to evaluate the effect of three adhesive systems applied in different bonding strategies (etch-and-rinse, self-etch, and universal adhesive) and time-point application (immediately after the cavity access preparation or after endodontic obturation) on the hybrid layer formation and dentinal penetrability. Materials and Methods: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used and the time-point application: Adper Scotchbond Multi-purpose (AS), Clearfil SE (CF) and Scotchbond Universal (SU) in strategy of immediate endodontic sealing (IES) or delayed endodontic sealing (DES). In IES-AS, IES-CF, and IES-SU groups, dentin sealing was performed immediately after the cavity access, while in DES-AS, DES-CF, and DES-SU, after root canal obturation. The specimens were sectioned in the long axis, in a buccal-lingual direction, and the dentinal penetrability of the adhesive systems was evaluated using confocal microscopy images. Hybrid layer formation was analyzed by scanning electron microscopy images. Statistical Analysis Used: Dentinal penetrability data were analyzed with the ANOVA test and the Kruskal–Wallis test was performed for hybrid layer data (α = 0.05). Results: IES-CF showed the lowest dentinal penetrability (P &lt; 0.05), while the other protocols were similar to each other (P &gt; 0.05). No significant differences were found between groups regarding the hybrid layer formation (P &gt; 0.05). Immediate and DES protocols do not influence the hybrid layer formation, regardless of the bond strategy used. Conclusions: Sealing the pulp chamber dentin before endodontic treatment can improve the bond strength of the final restoration but the formation of the hybrid layer was not influenced by the bond strategy.

The first composite increment: Dependency on placement technique for interaction behavior with maturing dentin-adhesive bond at pulpal floors in deep occlusal cavities – A comprehensive review

Abstract Introduction: When the traditional incremental technique is used for direct placement of composite resin in a deep occlusal cavity, each increment (2 mm or thicker) is individually cured where it undergoes hardening and shrinkage. As increments are bonded to all cavity walls, a constrained shrinkage develops in tooth, composite, and/or interfaces. In the first composite increment, this constrained shrinkage generates tensile stresses which are distributed in a nonuniform pattern within that increment, resulting in premature stressing of the dentin bond of the hybrid layer at the pulpal floor before it reaches full maturation. This premature stressing leads to initiation of interfacial debonding and propagation to form a microgap. This behavior is associated with persistent postoperative sensitivity and tooth pain, over the time, which subsequently results in restoration failure. Aims: This paper provides a comprehensive review on the first composite increment and its dependency on placement technique for the interaction behavior with the maturing dentin-adhesive bond at pulpal floors in deep occlusal cavities. Materials and Methods: The dental database was searched, and 59 articles were collected and included in this review, spanning the years from 1984 to 2023. Results and Discussion: Three biomimetic direct restorative techniques were reported in the literature for incrementally restoring large occlusal cavities. These techniques are the decoupling with time, the decoupling with fiber, and the decoupling with split-increment. They all aim at minimizing the generated shrinkage stresses in the first composite increment for protecting the developing dentin bond of the hybrid layer until it reaches full maturation and thus preventing the initiation and propagation of interfacial defects at pulpal floors of deep occlusal cavities. Finally, the restoration is completed by placing and curing successive increments of 1.5 mm each to fill the cavity; their number depends on the cavity depth. These increments can each be cured immediately following placement. Conclusions: In deep occlusal cavities, the interaction behavior between the first composite increment and the maturing dentin-adhesive bond at the pulpal floor depends on the technique used for the increment placement. This behavior is either favorable with the direct biomimetic techniques or unfavorable with the traditional incremental technique. With the direct biomimetic techniques, no premature shrinkage stressing of the dentin bond is induced at the pulpal floor. This prevents the initiation of interfacial debonding and propagation to form microgaps and results in the absence of postoperative sensitivity and persistent tooth pain.

Post-failure analysis of model resin-composite restorations subjected to different chemomechanical challenges

ObjectiveThe current study aimed to evaluate the effects of different combinations of chemical and mechanical challenges on the failure load, failure mode and composition of the resulting fracture surfaces of resin-composite restorations. MethodsThree resin composites were used to fill dentin disks (2 mm inner diameter, 5 mm outer diameter, and 2 mm thick) made from bovine incisor roots. The model restorations, half of which were preconditioned with a low-pH buffer (48 h under pH 4.5), were subjected to diametral compression with either a monotonically increasing load (fast fracture) or a cyclic load with a continuously increasing amplitude (accelerated fatigue). The load or number of cycles to failure was noted. SEM was performed on the fracture surfaces to determine the proportions of dentin, adhesive, and resin composite. ResultsBoth cyclic fatigue and acid preconditioning significantly reduced the failure load and increased the proportion of interfacial failure in almost all the cases, with cyclic fatigue having a more pronounced effect. Cyclic fatigue also increased the amount of adhesive/hybrid layer present on the fracture surfaces, but the effect of acid preconditioning on the composition of the fracture surfaces varied among the resin composites. SignificanceThe adhesive or hybrid layer was found to be the least resistant against the chemomechanical challenges among the components forming the model restoration. Increasing such resistance of the tooth-restoration interface, or its ability to combat the bacterial actions that lead to secondary caries following interfacial debonding, can enhance the longevity of resin-composite restorations.

Tunable polymer-peptide hybrids for dentin tissue repair

ObjectivesThis study targets to assess the remineralization capability of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). MethodsDentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanohardness, Masson's trichrome staining microscopy, and Raman analysis. ResultsDentin surfaces treated with TDg-NPs and load cycled produced higher nanohardness than the rest of the groups at the hybrid layer. At the bottom of the hybrid layer, all samples treated with TDg-NPs showed higher nanohardness than the rest of the groups. Active remineralization underneath the hybrid layer was detected in all groups after TDg application and load cycling, inducting new dentinal tubuli formation. After thermocycling, remineralization at the hybrid layer was not evidenced in the absence of NPs. Raman analysis showed increase mineralization, enriched carbonate apatite formation, and improved crosslinking and scaffolding of the collagen. ConclusionsMechanical loading on the specimens obtained after TDg-NPs dentin infiltration inducts an increase of mineralization at the resin/dentin interface, indicating remineralization of peritubular and intertubular dentin with augmented crystallographic maturity in crystals. Enriched collagen quality was produced, generating an adequate matrix organization to promote apatite nucleation, after tideglusib infiltration. Clinical significanceAt the present research, it has been proved the creation of reparative dentin, at the resin-dentin interface, after tideglusib dentin infiltration. Chemical stability, to favor integrity of the resin-dentin interface, is warranted in the presence of the TDg-NPs in the demineralized dentin collagen.

Influence of titanium dioxide nanotubes with alkyl ammonium alkyl bromide on the physicochemical properties and adhesion of experimental adhesive resins to dentin

ObjectiveThis study evaluated the effect of the incorporation of titanium dioxide nanotubes with alkyl trimethyl ammonium bromide (ntTiO2/ATAB) into experimental adhesive resins on their physicochemical properties and adhesion to dentin. Materials & methodsThe experimental adhesive resins were formulated with 66.66 wt% Bis-GMA and 33.33 wt% HEMA, photoinitiator with addition of ntTiO2/ATAB (1:1) in different concentrations: G1%, G2.5%, and G5%. One groups with no ntTiO2/ATAB addition was used as control (G0%). An optical tensiometer was used to analyze the contact angle (COA) by the sessile drop method (distilled water and α-bromonaphthalene) (n = 5), while the surface free energy (SFE) was calculated using Owens-Wendt-Rabel-Kaelble method. Flexural strength (FS) test (three-point bending) of polymerized adhesive samples was performed according to ISO 4049:2019 (n = 10) after 24 h or one year of water storage at 37 °C, as well as for the microtensile bond strength (μTBS) test, in which a commercial adhesive (GSBMP) was also used as control (n = 10). The adhesive-dentin interfaces were evaluated by scanning electron microscopy and X-ray spectrometry (n = 5). Data were analyzed by one-way (COA and SFE), two-way (FLE and μTBS) ANOVA and Tukey's test (α = 0.05). ResultsG5% showed the highest COA with nonpolar liquid and higher SFE than G0%. The G5% showed decreased FS compared to G0%. The μTBS of both controls (G0% and GSBMP) decreased after one year. TiO2/ATAB-containing adhesives to dentin showed no significant decrease after one year. All adhesives formed hybrid layer and the resin tags inside the dentinal tubules. ConclusionsThe incorporation of 1 and 2.5% of ntTiO2/ATAB into experimental adhesive resins did not impar the SFE. After one year, any concentration of ntTiO2/ATAB reduced the FS compared with control, but did not impair the μTBS.

Energy absorption and piezoresistive characteristics of 3D printed honeycomb composites with hybrid cell architecture

ABSTRACT This paper introduces a novel hybrid honeycomb (HC) design achieved by continuously blending non-auxetic hexagonal and auxetic re-entrant cell geometries along the out-of-plane direction. These novel hybrid HCs are additively manufactured via fused deposition modelling (FDM) using PA12 polymer reinforced with 15 wt.% of discontinuous carbon fibres. We study the mechanical and piezoresistive performance of hybrid HCs under quasi-static in-plane and out-of-plane loading performed at temperatures ranging between 25-125°C. The results demonstrate significant in-plane compression performance enhancements in the hybrid configuration, achieving up to 43% increase in the collapse strength and 119% in absorbed energy. The incorporation of multiple hybrid layers in the honeycomb structure further enhanced the in-plane properties, ultimately achieving a 181% enhancement in energy absorption. The hybrid honeycombs also showed a pronounced piezoresistive response with gauge factors in the range of 18–37 within the elastic regime, making them suitable for a wide range of multifunctional applications.

In Situ Construction of a Lithiophilic and Electronically Insulating Multifunctional Hybrid Layer Based on the Principle of Hydrolysis for a Stable Garnet/Li Interface

AbstractAdapting solid‐state Li‐metal batteries is an attractive way to pursue higher energy density and safety compared to liquid‐based ones. With high ionic conductivity and excellent stability with Li, Ta‐doped Li7La3Zr2O12 (LLZTO) is an effective option. However, the poor solid–solid interface contact induced by the lithiophobic Li2CO3 layer hinder its practical application. Herein, a versatile strategy is proposed based on the hydrolysis of sodium tetrafluoroborate (NaBF4), aiming to convert the Li2CO3 into multifunctional hybrid layer containing LiF, LiBO2, and NaF. Among them, LiF and LiBO2 serve as the primary Li ion conductors, the introduction of NaF with high surface energy not only enhances the interface wettability, but also further elevates the critical dendrite strength against Li dendrites. All three components serve as excellent electronic insulators, suppressing electron invasion at the interface and preventing Li dendrite growth in the solid electrolyte. As expected, the interfacial impedance of the NaBF4 treated symmetric cell is reduced to 6.0 Ω cm2, the critical current density (CCD) comes to 2.0 mA cm−2, and cycles over 3000 h at 0.3 mA cm−2 and 1500 h at 0.5 mA cm−2 respectively. Besides, the modified SSBs matched with LiFePO4 or LiNi0.6Co0.2Mn0.2O2 cathode show great long‐term cycling and rate performance.

Unveiling dendrite-suppressing potential of alkali metal-based alloys in lithium metal batteries

We reveal a concept of adding K and Na to dual-cation systems and investigate their effects on dendrite growth morphology and electrolyte decomposition reactivity in lithium metal batteries (LMBs). We analyze the effects of Li/K- and Li/Na-alloyed surfaces on Li ion diffusion along the deposition direction, as well as the reactivity of the electrolytes and the composition of the solid electrolyte interface (SEI) resulting from electrolyte decomposition. Compared with the Li/K system, the Li/Na-alloyed surface can significantly reduce Li diffusion along the z-direction and effectively prevent the formation of dendrite-like morphologies. Furthermore, the Li/Na-alloyed surface substantially mitigates the reactivity of the bis(fluorosulfonyl)imide (FSI−) anion and fluorinated ether (TTE) solvent, thus inhibiting the generation of excessive SEI species. Additionally, the regulated and simplified components of a hybrid LiF/NaF SEI layer in the Li/Na system are observed. This hybrid layer is expected to promote the uniform deposition of Li and exhibit excellent electrical insulating properties, thereby effectively preventing electron transfer to the electrolytes and enhancing the Coulombic efficiency of LMBs. This study presents new insights into the dendrite-suppressing potential of alkali-metal alloys for improving the stability and safety of LMBs.

Transforming Residual Lithium Compounds on the LiNi0.8Mn0.1Co0.1O2 Surface into a Li-Mn-P-O-Based Composite Coating for Multifaceted Improvements.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for next-generation lithium-ion batteries (LIBs). However, the chemical instability of the material during air exposure leads to the formation of residual lithium compounds (RLCs: LiOH and Li2CO3) on the surface and inhibits its practical application. Here, we propose a chemical conversion process to remove RLCs by utilizing them and forming a hybrid coating layer on the surface of NMC811 that contains Li3PO4, LiMn2O4, and LiMnPO4 phases, yielding multifaceted benefits. The hybrid layer on the surface protects the material from undesirable side reactions. It improves the cycle life of NMC811 by retaining 80% of its initial capacity after 300 cycles and 66% after 500 cycles at a 0.5C rate in the operating voltage of 3.0-4.3 V. The process enables high-voltage (4.7 V vs Li+/Li) operation by stabilizing the electrode-electrolyte interface, reduces the degree of cationic disorder and the voltage polarization for phase transitions, improves Coulombic efficiency and ion diffusion kinetics, and minimizes the secondary particle crack formation over long-term cycling. In fact, the coating reduces the detrimental effects of RLCs, leaves the surface for better Li+ transport, and hence significantly improves the electrochemical performance of NMC811.