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The author has formulated a qualitative method to determine the effective thermal conductivity variation in nanomaterials with respect to their dimension and size. The model includes the impact of shape, size, dimension and increased phonon scattering in nanomaterial due to the thermal resistance. In the present work, Guisbier’s top-down approach is used to obtain the thermal conductivity expression in terms of size and shape factor. The effective thermal conductivity of the nanomaterial is deduced using the effective medium approach that help to find the thermal conductivity in nanomaterial based on Kapitza thermal resistance effect. The model approach predicts the increment in the thermal conductivity of nanomaterial with size increment. The Kapitza thermal resistance in nanosolids results in increase in Phonon scattering in nanosolids with size reduction to nanoregime. The effective thermal conductivity is determined in AlN, GaN, GaAs, InAs and ZnO semiconducting compounds with respect to size in spherical and tetrahedral nanoparticles; cylindrical and parallelopiped nanowires and nanofilms. The model results obtained are compared with available experimental and simulated data. Good consistency between the compared results is observed in graphical representations. The model shows a drastic drop in effective thermal conductivity in nanosolids with their size reduction that increases the figure of merit in nanomaterials for using them in thermoelectric devices. [ABSTRACT FROM AUTHOR]

With the rapid development of high-power-density electronic devices, interface thermal resistance has become a critical barrier for effective heat management in high-performance electronic products. Therefore, there is an urgent demand for advanced thermal interface materials (TIMs) with high cross-plane thermal conductivity and excellent compressibility to withstand increasingly complex operating conditions. To achieve this aim, a promising strategy involves vertically arranging highly thermoconductive graphene on polymers. However, with the currently available methods, achieving a balance between low interfacial thermal resistance, bidirectional high thermal conductivity, and large-scale production is challenging. Herein, we prepared a graphene framework with continuous filler structures in in-plane and cross-plane directions by bonding corrugated graphene to planar graphene paper. The interface interaction between the graphene paper framework and polymer matrix was enhanced via surface functionalization to reduce the interface thermal resistance. The resulting three-dimensional thermal framework endows the polymer composite material with a cross-plane thermal conductivity of 14.4 W·m−1·K−1 and in-plane thermal conductivity of 130 W·m−1·K−1 when the thermal filler loading is 10.1 wt%, with a thermal conductivity enhancement per 1 wt% filler loading of 831%, outperforming various graphene structures as fillers. Given its high thermal conductivity, low contact thermal resistance, and low compressive modulus, the developed highly thermoconductive composite material demonstrates superior performance in TIM testing compared with TFLEX-700, an advanced commercial TIM, effectively solving the interfacial heat transfer issues in electronic systems. This novel filler structure framework also provides a solution for achieving a balance between efficient thermal management and ease of processing. [ABSTRACT FROM AUTHOR]

Lithium metal has been treated as one of the most promising anode materials for next-generation rechargeable batteries due to its extremely high theoretical capacity. However, its practical application is hindered by inhomogeneous lithium deposition and uncontrolled dendrite growth. In this work, we prepared a three-dimensional nickel foam (NF)-based current collector with a lithiophilic interface layer through facile hydrothermal and coating methods. The lithiophilic Ni3S2 array synthesized via a hydrothermal method has been demonstrated to facilitate the nucleation of Li+. Moreover, it has been observed that the outer coating comprising LPP effectively enhances the inward diffusion of Li+. Additionally, this interface layer can serve as an isolating barrier between the electrodes and the electrolyte. The prepared LPP-Ni3S2@Ni shows significant reversibility both in symmetric cells (1200 h, 1 mA cm−2) and half-cells (CE: 99.60%, 500 cycles, 1 mA cm−2) with low interfacial resistance (35 Ω). Full cells with LiFePO4 as a cathode also exhibit promising electrochemical performance with over 76.78% capacity retention over 200 cycles at 1 C. [ABSTRACT FROM AUTHOR]

The effect of high-intensity ultrasonic treatment (which can generate cavitation) on the microstructure of aluminum (Al) ingots has been widely studied. In this work, a stainless steel thin-walled sleeve was placed in a crucible to separate the 2219 Al melt into two parts: inside and outside the sleeve. By applying the ultrasound in the melt inside the sleeve, a low-intensity ultrasonic field (where the acoustic pressure is lower than the cavitation threshold) was introduced into the melt outside the sleeve. The influence of low-intensity ultrasound on the temperature gradient of the pasty melt as well as the refinement efficiency was explored. The result shows that low-intensity ultrasonic can induce high-frequency forced vibration to the grains and reduce the solid–liquid interfacial thermal resistance. In addition, by comparing the microstructure inside and outside the sleeve, it was found that there was no significant difference in the size and morphology of the grains and eutectic phase. This indicates that the cavitation effect is not necessary for grain refinement, and low-intensity ultrasonic can also produce a significant microstructure improvement on Al alloys. [ABSTRACT FROM AUTHOR]

In this work, we have developed ceramicized hybrid solid state electrolytes (SSEs), which consisted of poly (vinylidene fluoride-hexafluoro propylene) (PVDF-HFP), lithium bis (trifluoromethanesulfonyl)imide (LiTFSI) salt, and sodium superionic conductor (NASICON)-type Li1+xAlxTi2‒x(PO4)3 (LATP) powders for lithium-ion batteries (LIBs) utilizing lithium metal anode. Adopting the sol–gel synthesis technique followed by a thermal calcination at 850 °C, we synthesized round-like LATP powders with an average particle size of ~ 30 μm. Engineering the LATP content (~ 45 wt.%) within the hybrid SSEs, we were able to achieve thermal stability along with superior ionic conductivity (i.e., 1.40 × 10−4 S cm−1 at 30 °C). Employing the Arrhenius plot in the temperature range of 30‒70 °C, the activation energy for the ionic conduction was lowered significantly (i.e., 0.21 eV) compared to prior efforts reported in the literature (i.e., 0.27 − 0.35 eV). The application of highly optimized SSE within a LIB with lithium metal anode resulted in the maximal capacity of ~ 162 mAh g−1 at 0.1 C. The cyclic performance of the battery utilizing such an optimized SSE configuration was very robust with a highly stable coulombic efficiency (~ 96.7%) after 100 cycles. Indeed, the ceramicized LATP-based SSEs developed in this work, can be employed for boosting the ionic conductivity, specific capacity, and cycle life while mitigating the interfacial resistance of the electrolyte/electrode layer for LIBs with lithium metal anode. [ABSTRACT FROM AUTHOR]

The shrinking size of integrated chips poses thermal management challenges. Understanding the size effect of chemical heterogeneity on solid–liquid interfacial thermal transfer is essential for heterogeneous chip design, yet the underlying mechanisms remain lacking. The present work used the liquid n-alkanes as the thermal interface material between solid platinum substrates. To characterize chemical heterogeneity, periodic solid surface patterns composed of patches with alternating solid–liquid affinities were constructed. By using non-equilibrium molecular dynamics simulations, we investigated the size effect of chemically heterogeneous patterns on interfacial thermal resistance (ITR) at the nanoscale. At larger heterogeneity sizes, i.e., larger patch sizes, most alkane molecules directly in contact weak interaction patches cannot interact with strong interaction patches due to long atomic distances. In the case of alkanes in contact a cold substrate, alkanes in contact weak interaction patches transferred thermal energy to the substrate at a lower rate than those in contact strong interaction patches. The different rates resulted in the higher temperature of alkanes in contact weak interaction patches than those in contact strong interaction patches and, therefore, a larger disparity between temperature jump at the strong interaction areas and that at the weak interaction areas. The non-uniformity of temperature jump distribution increased ITR when compared to the heterogeneous surface system characterized by a smaller patch size with a more uniform temperature distribution in the plane perpendicular to the heat flux direction. In addition, the classical parallel thermal resistance model predicted ITR accurately for the heterogeneous surface systems with small size patches but overestimated overall thermal resistance. [ABSTRACT FROM AUTHOR]

The radio frequency (RF) power and noise temperature dependency of buffer-free layer AlGaN/GaN on the 6 in. SiC substrate high electron mobility transistor were studied. The buffer-free structure has improved 3% characteristics of the current collapse and pulse measurement at a 30 V drain quiescent voltage. Compared with the conventional thick buffer layer (1.5–2 μm) structure design, the buffer-free layer with high structural quality AlN nucleation layers can reduce self-heating and thermal boundary resistance effect when the devices operate at a high DC power. The buffer-free device exhibits lower surface temperatures and higher powers at the same VGS and VDS than the standard device in thermal imaging measurements. In addition, traditional iron- or carbon-doped buffers were avoided in this design; thus, the buffer-induced microwave noise and thermal noise can be improved simultaneously. Without Fe- or C-doped buffer-induced trap behavior, the buffer-free structure improves the device DC characteristics and reduces the current collapse effect from the conventional buffer; thus, the device shows better linearity, noise figure, and RF small-signal characteristics. [ABSTRACT FROM AUTHOR]

Solid‐state lithium batteries (SSLBs) with high safety have emerged to meet the increasing energy density demands of electric vehicles, hybrid electric vehicles, and portable electronic devices. However, the dendrite formation, high interfacial resistance, and deleterious interfacial reactions caused by solid–solid contact between electrode and electrolyte have hindered the commercialization of SSLBs. Thus, in this review, the state‐of‐the‐art developments in the rational design of solid‐state electrolyte and their progression toward practical applications are reviewed. First, the origin of interface instability and the sluggish charge carrier transportation in solid–solid interface are presented. Second, various strategies toward stabilizing interfacial stability (reducing interfacial resistance, suppressing lithium dendrites, and side reactions) are summarized from the physical and chemical perspective, including building protective layer, constructing 3D and gradient structures, etc. Finally, the remaining challenges and future development trends of solid‐state electrolyte are prospected. This review provides a deep insight into solving the interfacial instability issues and promising solutions to enable practical high‐energy‐density lithium metal batteries. [ABSTRACT FROM AUTHOR]

The coal-based direct reduction process has been coupled with the magnetic field-enhanced reduction technique. The effects of the magnetic field intensity on reduction efficiency, phase changes of the iron-bearing minerals, and reduction kinetic behavior have been investigated. The results showed that the reduction efficiency of Bayan Obo iron ore increased with the increase of the magnetic field intensity and extending the reduction time. Under the conditions of magnetic field intensity, B = 1.0 T, reduction time t = 60 min, and reduction temperature T = 950°C, the metallization rate of Bayan Obo iron ore was 93.42%. The relationship between reduction efficiency and magnetic field intensity and reduction time was revealed by a response surface method. In all stages of reduction, the effect of magnetic field intensity on the reduction efficiency of Bayan Obo iron ore was greater than that of reduction time. The relationship between the three was: M 0 ∼ 60 B , t = - 17.31 + 2.35 t + 28.72 B + 0.6 t B - 0.02 t 2 - 14.76 B 2 . The magnetic field made the reaction material looser, which not only reduced the diffusion resistance of the reducing gas CO but also increased the adsorption potential of CO at the reaction interface. Compared with B = 0.0 T, for B = 1.0 T, the internal diffusion resistance and the interfacial chemical reaction rate were 5.08 times and 0.79 times higher, respectively. [ABSTRACT FROM AUTHOR]

High‐power‐density rechargeable batteries are highly indispensable for power‐intensive application scenarios, such as vehicle start‐stop system and grid‐level frequency regulation. However, realizing high‐power‐density alkali‐ion batteries is challenging especially at low temperatures, as undesirable alkali metal plating tends to occur more easily on the anode surface due to the increased electrochemical impedance and polarization. Herein, a low‐temperature, high‐power‐density rechargeable Na3V2(PO4)3 ||hard carbon (HC) sodium‐ion full battery without Na plating is realized by electrolyte regulation. The designed high‐solvation‐entropy electrolyte enables a high ionic conductivity of 13.87 mS cm−1 at −40 °C. More importantly, the enhanced contact‐ion pairs solvation structure induces an anion‐derived, thin, NaF‐rich solid electrolyte interface (SEI) on HC anodes with low interfacial resistance to ensure facile Na+ diffusion through the SEI. Consequently, the assembled sodium‐ion full battery demonstrates a record‐high power density of 1132.31 W kg−1 (with an energy density of 61.94 Wh kg−1) at −40 °C and 13372.56 W kg−1 (132.83 Wh kg−1) at 25 °C (based on total mass of the active materials on anode and cathode). This work will expedite the development of sodium‐ion batteries for power‐intensive applications in extreme environments. [ABSTRACT FROM AUTHOR]

The polymer electrolyte membrane fuel cells are proven to be clean renewable energy conversion systems; however, the cylindrical structures have numerous potentials in low-power applications owing to their higher gravimetric and volumetric power densities. In this study, a three-dimensional axisymmetric computational fluid dynamics model is developed for a cylindrical structure and is further validated for cell performance at different clamping pressures (0.5–2.5 MPa). The optimum contact resistance for the cell is observed to be 0.40 Ω-cm2 for a clamping pressure of 1.5 MPa at the interface of the cathode gas diffusion layer and cathode current collector. In addition, a structural model is developed with the variation in thickness of the cathode current collector (0.25–1.5 mm) and gas pressure (0.5–3.0 bar) for different clamping systems. The results indicate an enhancement in the cell performance (58.58 W/m2 to 138.96 W/m2 at 0.6 V) with optimum clamping (1.5 MPa) and gas pressure (1 bar) due to better contact pressure distribution at the interface. The thickness of the cathode current collector is also optimized to 1.0 mm for a new (spring) clamping system owing to ∼1.6 times better contact and 66% less resistance to that of conventional (strap) clamping mechanism. • A cylindrical polymer electrolyte membrane fuel cell is modelled using an axisymmetric approach. • Effect of thickness of cathode current collector with strap and spring clamping method is analysed. • Interfacial contact resistance and its effect on cell performance due to clamping and gas pressure are estimated [ABSTRACT FROM AUTHOR]

Incorporating lithium metal anodes in next‐generation batteries promises enhanced energy densities. However, lithium's reactivity results in the formation of a native surface film, affecting battery performance. Therefore, precisely controlling the chemical and morphological surface condition of lithium metal anodes is imperative for producing high‐performance lithium metal batteries. This study demonstrates the efficacy of laser treatment for removing superficial contaminants from lithium metal substrates. To this end, picosecond‐pulsed laser radiation is proposed for modifying the surface of lithium metal substrates. Scanning electron microscopy (SEM) revealed that different laser process regimes can be exploited to achieve a wide spectrum of surface morphologies. Energy‐dispersive X‐ray spectroscopy (EDX) confirmed substantial reductions of ≈80% in oxidic and carbonaceous surface species. The contamination layer removal translated into interfacial resistance reductions of 35% and 44% when testing laser‐cleaned lithium metal anodes in symmetric all‐solid‐state batteries (ASSBs) with lithium phosphorus sulfur chloride (LPSCl) and lithium lanthanum zirconium oxide (LLZO) solid electrolytes, respectively. Finally, a framework for integrating laser cleaning into industrial battery production is suggested, evidencing the industrial feasibility of the approach. In summary, this work advances the understanding of lithium metal surface treatments and serves as proof of principle for its industrial applicability. [ABSTRACT FROM AUTHOR]

Aqueous zinc (Zn)‐based structural batteries capable of both electrochemical energy storage and mechanical load‐bearing capabilities are attractive for next‐generation energy storage for future electric vehicles due to their eco‐friendliness, non‐toxic, and safe nature. However, parasitic free water activities plague aqueous Zn‐based batteries, detrimental to the electrochemical performance and longevity of the cell. Developing polymer gel electrolytes is a notable potential solution, but they usually have poor electrode interfacial interactions and inadequate mechanical properties. This article introduces a novel non‐fibrous highly amorphous cellulose polymer electrolyte "Cellyte" for aqueous structural Zn‐based batteries. Cellyte exhibits a high strength of ≈24 MPa and Young's modulus of ≈380 MPa, along with the ability to suppress parasitic water activity. The symmetric Zn||Cellyte||Zn cell therefore demonstrates excellent cycling stability of over ≈3000 h. Cellyte can also serve as the binder for the structural cathode material, creating a continuous polymer electrolyte–cathode interface, thereby increasing mechanical robustness and decreasing interfacial resistances of the battery, allowing the structural Zn||Cellyte||LMO‐CF battery to achieve high electrochemical performance with excellent cycling stability over 1200 h with ≈91.5% capacity retention. This provides a pathway to design mechanically robust, electrochemically performing, and safe structural batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing surface structuring of Al current collectors for battery application. • Developing crack formation on the electrodes to enhance electrolyte diffusion. • Improving electrode adhesion using structured Al current collectors. • Crack formation enabling fast charging-rates and battery cycle life. Today's society and economy demand high-performance energy storage systems with large battery capacities and super-fast charging. However, a common problematic consequence is the delamination of the mass loading (including, active materials, binder and conductive carbon) from the current collector at high C-rates and also after certain cycle tests. In this work, surface structuring of aluminum (Al) foils (as a current collector) is developed to overcome the aforementioned delamination process for sulfur (S)/carbon composite cathodes of Li-S batteries (LSBs). The structuring process allows a mechanical interlocking of the loaded mass with the structured current collector, thus increasing its electrode adhesion and its general stability. Through directed crack formation within the mass loading, this also allows an enhanced electrolyte wetting in deeper layers, which in turn improves ion transport at increased areal loadings. Moreover, the interfacial resistance of this composite is reduced leading to an improved battery performance. In addition, surface structuring improves the wettability of water-based pastes, eliminating the need for additional primer coatings and simplifying the electrode fabrication process. Compared to the cells made with untreated current collectors, the cells made with structured current collectors significantly improved rate capability and cycling stability with a capacity of over 1000 mAh g−1. At the same time, the concept of mechanical interlocking offers the potential of transfer to other battery and supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

The plateau‐type sodium titanate with suitable sodiation potential is a promising anode candidate for high safe and high energy density of sodium‐ion batteries (SIBs). However, the poor initial Coulombic efficiency (ICE) and cyclic instability of sodium titanate are attributed to the unstable interfacial structure along with the decomposition of electrolytes, resulting in the continuous formation of solid electrolyte interface (SEI) film. To address this issue, a chemical grafting method is developed to fabricate a highly stable interface layer of inert Al2O3 on the sodium titanate anode, rendering the high ICE and excellent cycling stability. Based on theoretical calculations, NaPF6 are more likely adsorption on the Al2O3 surface and produce sodium fluoride. The formation of a thin and dense SEI film with rich sodium fluoride achieves the low interfacial resistances and charge‐transfer resistances. Benefitting from our design, the obtained sodium titanate exhibits a high ICE from 67.7 % to 79.4 % and an enhanced reversible capacity from 151 mAh g−1 to 181 mAh g−1 at 20 mA g−1, along with an increase in capacity retention from 56.5 % to 80.6 % after 500 cycles. This work heralds a promising paradigm for rational regulation of interfacial stability to achieve high‐performance anodes for SIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • CNTs-related composite PCMs are categorized in a new way: CNTs are usd as nanoadditives, porous supporters, and secondary network. • The research progress in the mechanism of heat transfer and phase transition of CNTs-related composite PCMs is introduced in detail. • In-depth insights into the micro-mechanism of heterogeneous interactions induced by CNTs are revealed. • The current challenges of designing CNTs-related composite PCMs are summarized. With the merits of inherent physicochemical properties of hollow structure, high mechanical strength, thermal stability, ultrahigh light absorption capacity, and ultrahigh thermal conductivity, carbon nanotubes (CNTs) are extensively used to enhance the thermal storage capabilities of solid–liquid phase change materials (PCMs). Interestingly, CNTs can act as thermally conductive additives and supporting skeletons when marring with PCMs. The state-of-the-art reviews on PCMs pay attention to carbon-based porous composite PCMs or nanoparticle dispersed PCMs, CNTs-derived PCMs only share a small part, lacking of a comprehensive review for multifunctional CNTs compounded PCMs. Herein, focusing on the enhancement effects of CNTs on PCMs, we retrospectively describe composite PCMs with a novel category way, by using CNTs as nanoadditives, porous supporters, and secondary network. We emphasize the micro-mechanism of heterogeneous interactions induced by CNTs: crystallization behavior, interfacial thermal resistance, thermal conductivity, phonon transport. Simultaneously, we provide in-depth insight into relationship between micro structural and thermal properties of CNT-derived PCMs. As a result, some different pathways of modern utilization based on the improved PCMs are presented. Finally, we outline the current challenges of designing CNTs to enable advanced functional thermal storage materials. The review aims to inspire clever use of CNTs into PCMs for targeted applications. [ABSTRACT FROM AUTHOR]

Composite materials and structural optimization are important research topics in heat transfer enhancement. The current evaluation parameter for the conductive heat transfer capability of composites is effective thermal conductivity (ETC); however, this parameter has not been studied or analyzed for its applicability to different heat transfer models and composite structures. In addition, the optimized composite structures of a specific object will vary when different optimization methods and criteria are employed. Therefore, it is necessary to investigate a suitable method and parameter for evaluating the heat transfer capability of optimized composites under different heat transfer models. Therefore, this study analyzes and summarizes three typical conductive heat transfer models: surface-to-surface (S-to-S), volume-to-surface (V-to-S), and volume-to-volume (V-to-V) models. The equivalent thermal conductivity ( k eq ) is proposed to evaluate the conductive heat transfer capability of topology-optimized composite structures under the three models. A validated simulation method is used to obtain the key parameters for calculating k eq . The influences of the interfacial thermal resistance and size effect on k eq are considered. The results show that the composite structure optimized for the V-to-S and V-to-V models has a k eq value of only 79.4 W m−1 K−1 under the S-to-S model. However, the k eq values are 233.4 W m−1 K−1 and 240.3 W m−1 K−1 under the V-to-S and V-to-V models, respectively, which are approximately 41% greater than those of the in-parallel structure. It can be demonstrated that k eq is more suitable than the ETC for evaluating the V-to-S and V-to-V heat transfer capabilities of composite structures. The proposed k eq can serve as a characteristic parameter that is beneficial for heat transfer analysis and composite structural optimization. [ABSTRACT FROM AUTHOR]

A crucial problem in the design of heat exchangers (HEx) for dilution refrigerators is thermal boundary resistances between liquid helium and substances rapidly increasing at low temperatures. In addition, thermal resistivity of liquid helium in restricted geometries also increases with decreasing temperature. To solve these problems, recently we developed the nanopore heat exchanger (NHEx), where nanoporous silicate and 75000-nm silver powder are used. Nanoporous materials have huge specific area about of 1000 m 2 /g, which is 3 orders larger compared with conventional fine silver powder sinters widely used for HExs. We have measured the Kapitza resistance of NHEx down to 22 mK and found that it is nearly 10 times smaller than that of conventional sinters with the same size. Use of 75000-nm silver powder instead of 70 nm also allows to reduce thermal resistivity of the liquid. In order to examine performance of the NHEx, quantitative evaluation is performed using numerical simulations. The result shows 3–10 times better performance of NHEx, compared with conventional HExs. [ABSTRACT FROM AUTHOR]

As an emerging wide-bandgap semiconductor material, β-Ga 2 O 3 has extensive application prospect in high power operating environments due to its excellent electrical properties, but low thermal conductivity and anisotropy bring challenges in device heat dissipation. Heterogeneous integration of β-Ga 2 O 3 with high thermal conductivity substrates might improve thermal dissipation efficiency and device operational stability. However, heterogeneous integration introduces thermal boundary resistance (TBR) between the β-Ga 2 O 3 and the substrate, and it is necessary to investigate proper heterogeneous integration processes to reduce the TBR. In this work, we compare the thermal boundary conductance (TBC) between Ga 2 O 3 and different semiconductors with the Acoustic Mismatch Model (AMM) and Diffusion Mismatch Model (DMM). Molecular dynamics (MD) simulations show that the [010] crystallographic direction of β-Ga 2 O 3 exhibited the highest thermal conductivity and higher TBC with most semiconductors except BN and Diamond. To enhance the thermal transport between β-Ga 2 O 3 and the most widely used SiC substrate, SiO 2 thin film is introduced as an interlayer, and the TBC is enhanced by 3.7 folds. The SiO 2 interlayer can bridge the vibration between β-Ga 2 O 3 and SiC by improving the overlap energy and phonon participation ratio. These research findings provide guides for the selection of substrates and interlayers in heterogeneous integration for β-Ga 2 O 3 device thermal management. [ABSTRACT FROM AUTHOR]

Employing quasi-solid-state gel polymer electrolyte (GPE) instead of the liquid counterpart has been regarded as a promising strategy for improving the electrochemical performance of Li metal batteries. However, the poor and uneven interfacial contact between Li metal anode and GPE could cause large interfacial resistance and electrochemical Li stripping/plating inhomogeneity, deteriorating the electrochemical performance. Herein, we proposed that the functional component of composite anode could work as the catalyst to promote the in situ polymerization reaction, and we experimentally realized the integration of polymerized-dioxolane electrolyte and Li/Li22Sn5/LiF composite electrode with low interfacial resistance and good stability by in situ catalyzation polymerization. Thus, the reaction kinetics and stability of metallic Li anode were significantly enhanced. As a demonstration, symmetric cell using such a GPE-Li/Li22Sn5/LiF integration achieved stable cycling beyond 250 cycles with small potential hysteresis of 25 mV at 1 mA·cm−2 and 1 mAh·cm−2, far outperforming the counterpart regular GPE on pure Li. Paired with LiNi0.5Co0.3Mn0.2O2, the full cell with the GPE-Li/Li22Sn5/LiF integration maintained 85.7% of the original capacity after 100 cycles at 0.5 C (1 C = 200 mA·g−1). Our research provides a promising strategy for reducing the resistance between GPE and Li metal anode, and realizes Li metal batteries with enhance electrochemical performance. [ABSTRACT FROM AUTHOR]

Developing flexible thermal management materials is quite urgent for emerging flexible electronics and wearable devices. Here, a novel strategy is used to prepare hydroxyl-functionalized boron nitride@polyurethane (BNOH@PU) composites with desired BN orientation in the in-plane direction through the foaming process of PU and hot-pressing. BNOH flakes can react with isocyanates to form amido linkages, which is beneficial for reducing interfacial thermal resistance (ITR) between BNOH and PU. In addition, BNOH flakes will be rearranged along the direction of PU backbones through the volume compression of the foaming process and trend to be oriented in the in-plane direction after hot-pressing. The out-of-plane or in-plane thermal conductivities of the composites are 1.69 and 3.19 W m−1 K−1 at 30 wt% BNOH content, and the corresponding thermal conductivity enhancement (TCE) is 1986% and 3838%, respectively. Meanwhile, BNOH@PU exhibited low ITR between BNOH flakes (1.252 × 10−7 K m2/W), good flexibility and stretchability, which was a promising thermal management material for wearable devices. The interfacial thermal resistance (ITR) and the phonon scattering between fillers and polymer matrix could be reduced significantly via the hydroxyl functionalization of BN. In-plane thermal conductivity enhanced BNOH@PU composites with desired BN orientation in the in-plane direction through the foaming process of PU and hot-pressing. [ABSTRACT FROM AUTHOR]

Highlights: A composite thermal interface material with three-dimensional hybrid carbon network-reinforced polydimethylsiloxane was proposed. The cooperative regulation of thermal conductivity and mechanical properties was achieved by controlling the assembly process of micro-nano scale unit carbon materials. The orthotropic continuous carbon structure endowed the composites with in-plane and out-of-plane thermal conductivities of up to 113.61 and 24.37 W m−1 K−1, respectively. The excellent compressibility and adhesion properties cooperatively improved the effective thermal conductivity by more than an order of magnitude. Vertically oriented carbon structures constructed from low-dimensional carbon materials are ideal frameworks for high-performance thermal interface materials (TIMs). However, improving the interfacial heat-transfer efficiency of vertically oriented carbon structures is a challenging task. Herein, an orthotropic three-dimensional (3D) hybrid carbon network (VSCG) is fabricated by depositing vertically aligned carbon nanotubes (VACNTs) on the surface of a horizontally oriented graphene film (HOGF). The interfacial interaction between the VACNTs and HOGF is then optimized through an annealing strategy. After regulating the orientation structure of the VACNTs and filling the VSCG with polydimethylsiloxane (PDMS), VSCG/PDMS composites with excellent 3D thermal conductive properties are obtained. The highest in-plane and through-plane thermal conductivities of the composites are 113.61 and 24.37 W m−1 K−1, respectively. The high contact area of HOGF and good compressibility of VACNTs imbue the VSCG/PDMS composite with low thermal resistance. In addition, the interfacial heat-transfer efficiency of VSCG/PDMS composite in the TIM performance was improved by 71.3% compared to that of a state-of-the-art thermal pad. This new structural design can potentially realize high-performance TIMs that meet the need for high thermal conductivity and low contact thermal resistance in interfacial heat-transfer processes. [ABSTRACT FROM AUTHOR]

Here, the sodium storage mechanism in commercial grade hard carbon with a low surface area is comprehensively investigated using electrochemical impedance spectroscopy (EIS), the galvanostatic intermittent titration technique, and in situ Raman spectroscopy for fresh and cycled electrodes. The reversible shift of the carbon G‐band peak on Raman spectra and substantial change of the charge‐transfer resistance in the sloping region of the voltage profile indicates the intercalation of sodium ions into hard carbon, whereas the low‐voltage plateau is associated with the pore‐filling process. In situ Raman analysis at low frequencies reveals that the pore filling is progressed via formation of small sodium clusters in closed pores. Prolonged cycling demonstrates that intercalation is stable and consistent throughout multiple charge–discharge cycles. The transition from intercalation to pore filling strongly affects the diffusion behavior, leading to considerably slower diffusivity at low voltage. The EIS effectively differentiates the contribution of adsorption to charge storage. The gradual growth of the solid‐electrolyte interphase layer affects the rise of the interfacial resistance as cycling progresses. In combination with the slower diffusivity, the low‐voltage plateau region strictly impedes fast de/sodiation and eventually causes capacity fade. [ABSTRACT FROM AUTHOR]

Adding additives (e.g., carbon dots, CDs) to liquid lubricants is an effective method for enhancing their load‐bearing capacity and friction reduction. However, it is challenging to simultaneously impart high load‐bearing capacity and superlubricity for them (e.g., ionic liquid analogs, ILAs) through this strategy due to strong Coulombic interactions. With CDs as a competing ligand operon, the cluster size distribution can be expanded, conferring superlubricity with ultrahigh load‐bearing capacity (>705 MPa, the highest value of CDs‐based superlubricious materials thus far) for CDs/ILAs. In particular, methodologies such as Raman, 1H‐NMR, fourier transform infrared spectroscopy, and laser particle size analysis are employed to characterize the evolution of their H‐bonding interactions and particle size distribution. CDs can act as competing ligands and enable CDs/ILAs to form systems with ultra‐low coefficient of friction and wear consisting of a mixture of large and small clusters. The mixed and expanded size clusters facilitate the reduction of the viscosity for CDs/ILAs under shear, thereby reducing the interfacial shear resistance during superlubricity, while the CDs within them efficiently transfer the normal bearing loads. The progress is made from the perspective of cluster particle size distribution rather than individual additive properties, providing a new avenue for designing ILAs‐based superlubricious materials. [ABSTRACT FROM AUTHOR]

Featuring high theoretical capacity, low cost, and low preparation temperature, Li‐free cathodes are considered promising for all‐solid‐state thin‐film lithium microbatteries (TFBs). In this work, a Li‐free cathode of amorphous FeOxSy film is prepared, followed by the fabrication and investigation of FeOxSy/LiPON/Li TFBs. It is found that the structural degradation at both the LiPON/Li and FeOxSy/LiPON interfaces results in a rapid capacity loss for the TFB during electrochemical cycling. To achieve both high rate capability and long cycle life for the TFB, a dual‐interface modification approach using amorphous Al2O3 as an interlayer is proposed. During the TFB cycling, the Al2O3 interlayer not only enables robust LiPON/Li contact by preventing the formation of Li voids but also blocks the diffusion of Fe element from FeOxSy to LiPON electrolyte, effectively suppressing the interfacial resistance growth. Consequently, the dual‐interface modified TFB achieves greatly improved rate capability (194.3 mAh g−1 at 5 A g−1) and cycle performance (71% capacity retention after 800 cycles), which are superior to the pristine TFB and single‐interface modified TFB. This work advances the fundamental understanding of the failure mechanisms at the solid‐solid electrode/electrolyte interfaces, offering a feasible interfacial modulation strategy to develop advanced all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

The inherent structural properties and elevated processing temperatures of thermoplastic resins present new challenges in the realm of carbon fiber (CF) sizing agents. Consequently, a water‐based cross‐linkable nitro‐phthalonitrile capped polyfluorenyl ether ketone sizing agent was meticulously designed. The sizing agent exhibits superior storage stability, encapsulating particles spanning dimensions from 66.51 to 87.71 nm. The inherent mechanism during the hot‐pressing stage involves a self‐crosslinking of nitrile groups toward stable structures with unparalleled resistance to solvents. The crosslinked sizing agent boasts a remarkable glass‐transition temperature of 290°C. Noteworthy, significance is the consequential 40.1% augmentation in maximum flexural strength, along with a commendable 35% increase in interlaminar shear strength for CF‐1.5/PEEK composites in contrast to their unsized CF/PEEK counterparts. In summary, the focal aspiration of this research endeavor lies in offering a straightforward and viable methodology for the exploration of cross‐linkable sizing agents, strategically catering to both "thermoplastic processing" and "thermosetting applications." Highlights: Bulky fluorenyl unit increases the intermolecular volume of copolymer poly(fluorenyl ether ketone).The introduction of the BPF unit to the molecular elevates the thermal stability of the copolymer.Unique electron‐donating proclivity of the fluorenyl group drastically improved its reactivity.The polymerization was accomplished at a relatively low temperature of 150°C for practical applications.The ILSS, IFSS, and bending strength were noteworthy increased by 35%, 74.02%, and 40.1% [ABSTRACT FROM AUTHOR]

The mechanical performance of parts produced by fused filament fabrication (FFF) has been limited due to the presence of voids and poor interlayer welding. Recent advancements in FFF have enabled the fabrication of void‐free objects with strong interlayer welding through the use of semicrystalline polymer shells such as high‐density polyethylene (HDPE) along with a high viscosity core polymer like acrylonitrile‐butadiene‐styrene (ABS). The zero‐shear viscosity (η0) of ABS is three orders of magnitude higher than HDPE making the ABS‐HDPE core‐shell configuration preferable. ABS holds the shape by preventing bulk flow and part bending while HDPE promotes full surface contact across the layers. Most polymers, however, are immiscible which causes a weak weld line along the core‐shell interface. Herein, maleic anhydride (MAH) is grafted to the butadiene segment of the ABS core thereby compatibilizing the interface with HDPE, improving the interfacial adhesion. Attenuated total reflectance‐Fourier transform infrared spectroscopy was employed to confirm successful grafting. Using a custom‐made die affording the core‐shell structure, the ABS‐g‐MAH is shown to improve the impact resistance by 253% and 16% compared to neat HDPE and ABS specimens, respectively. Additionally, a 10% increase compared to the unmodified ABS‐HDPE core‐shell configuration is observed. [ABSTRACT FROM AUTHOR]

This study reports five types of metal-doped (Co, Cu, Sn, V, and Zr) NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP)/polymer composite solid electrolytes (CSEs) enabling Li4Ti5O12 (LTO) anodes to have high rate capability and excellent cycling performance. The high Li+-conductivity LATP samples are successfully synthesized through a modified sol–gel method followed by thermal calcination. We find that the cation dopants clearly influence the substitution of Al for Ti, with the type of dopant serving as a crucial factor in determining the ionic conductivity and interfacial resistance of the solid electrolyte. The CSE containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Sn-LATP shows an ionic conductivity of 1.88 × 10−4 S cm−1 at ambient temperature. The optimum conductivity can be attributed to alterations in the lattice parameters and Li+ transport pathways owing to Sn doping. The solid-state cell equipped with the LTO-supported CSE containing Sn-LATP fillers demonstrates both excellent high rate capability at 5 C (with a capacity retention of 86% compared to the value measured at 0.2 C) and superior cycling stability, maintaining high Coulombic efficiency (>99.0%) over 510 cycles. These findings indicate that the proposed CSE is highly promising for use in solid-state lithium batteries with desirable charge–discharge properties and high durability. [ABSTRACT FROM AUTHOR]

The fundamental solution describing non-stationary elastic wave scattering on an isotopic defect in a one-dimensional harmonic chain is obtained in an asymptotic form. The chain is subjected to unit impulse point loading applied to a particle far enough from the defect. The solution is a large-time asymptotics at a moving point of observation, and it is in excellent agreement with the corresponding numerical calculations. At the next step, we assume that the applied point impulse excitation has random amplitude. This allows one to model the heat transport in the chain and across the defect as the transport of the mathematical expectation for the kinetic energy and to use the conception of the kinetic temperature. To provide a simplified continuum description for this process, we separate the slow in time component of the kinetic temperature. This quantity can be calculated using the asymptotics of the fundamental solution for the deterministic problem. We demonstrate that there is a thermal shadow behind the defect: the order of vanishing for the slow temperature is larger for the particles behind the defect than for the particles between the loading and the defect. The presence of the thermal shadow is related to a non-stationary wave phenomenon, which we call the anti-localization of non-stationary waves. Due to the presence of the shadow, the continuum slow kinetic temperature has a jump discontinuity at the defect. Thus, the system under consideration can be a simple model for the non-stationary phenomenon, analogous to one characterized by the Kapitza thermal resistance. Finally, we analytically calculate the non-stationary transmission function, which describes the distortion (caused by the defect) of the slow kinetic temperature profile at a far zone behind the defect. [ABSTRACT FROM AUTHOR]

With the rapid development of nanotechnology, using the applied electric field to regulate interfacial heat transfer has become increasingly important. In the present work, the relationship between the thermal resistance of Kapitza and the direction of the applied electric field is explored with nonequilibrium molecular dynamics method at a solid–liquid interface consisting of CU (0, 0, 1) and liquid water. It found that the electric field orientation induces the ordering of water molecules near the solid, which affects the magnitude of the Kapitza thermal resistance. In addition, the electric field orientation affects the degree of mismatch between solid and liquid vibrational dynamical density (VDOS), which affects the phonon transport at the solid–liquid interface, and ultimately affects the process of interfacial heat transfer. Furthermore, it's found that there is a weak correlation between the interfacial thermal resistance and the dimension of the copper-water model. [ABSTRACT FROM AUTHOR]

A novel DC-assisted fast hot-pressing (FHP) powder sintering technique was utilized to prepare Al/Diamond composites. Three series of orthogonal experiments were designed and conducted to explore the effects of sintering temperature, sintering pressure, and holding time on the thermal conductivity (TC) and sintering mechanism of an Al-50Diamond composite. Improper sintering temperatures dramatically degraded the TC, as relatively low temperatures (≤520 °C) led to the retention of a large number of pores, while higher temperatures (≥600 °C) caused unavoidable debonding cracks. Excessive pressure (≥100 MPa) induced lattice distortion and the accumulation of dislocations, whereas a prolonged holding time (≥20 min) would most likely cause the Al phase to aggregate into clusters due to surface tension. The optimal process parameters for the preparation of Al-50diamond composites by the FHP method were 560 °C-80 MPa-10 min, corresponding to a density and TC of 3.09 g cm−3 and 527.8 W m−1 K−1, respectively. Structural defects such as pores, dislocations, debonding cracks, and agglomerations within the composite strongly enhance the interfacial thermal resistance (ITR), thereby deteriorating TC performance. Considering the ITR of the binary solid-phase composite, the Hasselman–Johnson model can more accurately predict the TC of Al-50diamond composites for FHP technology under an optimal process with a 3.4% error rate (509.6 W m−1 K−1 to 527.8 W m−1 K−1). The theoretical thermal conductivity of the binary composites estimated by data modeling (Hasselman–Johnson Model, etc.) matches well with the actual thermal conductivity of the sintered samples using the FHP method. [ABSTRACT FROM AUTHOR]

The global environmental crisis necessitates reliable, sustainable, and safe energy storage solutions. The current systems are nearing their capacity limits due to the reliance on conventional liquid electrolytes, which are fraught with stability and safety concerns, prompting the exploration of solid-state electrolytes, which enable the integration of metal electrodes. Solid-state sodium-ion batteries emerge as an appealing option by leveraging the abundance, low cost, and sustainability of sodium. However, low ionic conductivity and high interfacial resistance currently prevent their widespread adoption. This study explores polyvinyl-based polymers as wetting agents for the NASICON-type NZSP (Na3Zr2Si2PO12) solid electrolyte, resulting in a combined system with enhanced ionic conductivity suitable for Na-ion solid-state full cells. Electrochemical impedance spectroscopy (EIS) performed on symmetric cells employing NZSP paired with different wetting agent compositions demonstrates a significant reduction in interfacial resistance with the use of poly(vinyl acetate)—(PVAc-) based polymers, achieving an impressive ionic conductivity of 1.31 mS cm−1 at room temperature, 63.8% higher than the pristine material, notably reaching 7.36 mS cm−1 at 90 °C. These results offer valuable insights into the potential of PVAc-based polymers for advancing high-performance solid-state sodium-ion batteries by reducing their total internal resistance. [ABSTRACT FROM AUTHOR]

Li metal is a promising negative-electrode material for high-energy-density all-solid-state batteries. However, the surface of Li metal is prone to oxidation, which results in the formation of a contamination layer at the Li metal–solid electrolyte interface. This interfacial contamination layer is the root cause of short-circuiting and poor cycle stability, thus hindering the development of all-solid-state batteries. Prior studies have not quantitatively assessed the effect of the above layer on battery performance. Herein, the degradation mechanisms affecting the interface are investigated using alternating-current impedance measurements and Li plating–stripping cycle tests for a symmetric cell. A thin contamination layer results in a Li–electrolyte interface with a low resistance of 0.20 kΩ cm2 and stable Li plating–stripping behavior at a current density of 3 mA cm−2, whereas a thick contamination layer results in a high interfacial resistance of 2.0 kΩ cm2. The thinning of the contamination layer on Li metal enhances the stability of the Li–electrolyte interface and Li plating–stripping kinetics. [ABSTRACT FROM AUTHOR]

The construction of semiconductor heterojunctions had been proven a promising strategy for improving the efficiency of photo-induced charge separation, maximizing the utilization of spectral energy, and improving redox activity for efficient environmental treatment. In this work, the PCN/BiVO4 composites were constructed by coupling nano-layered g-C3N4(PCN) with co-exposed {010} and {110} planes of BiVO4 crystals. Morphology analysis demonstrated that PCN tightly wrapped around the co-exposed {010} and {110} planes of BiVO4 crystals. The FTIR and XPS analysis confirmed that there was interfacial interaction between PCN and BiVO4. The PCN/BiVO4 composites exhibited enhanced photocatalytic degradation properties for methylene blue dyes as compared to pristine PCN and BiVO4, which was attributable to the surface and interface heterojunctions, effectively suppressing the recombination of photogenerated electro-holes pairs. Moreover, the 10-PCN/BiVO4 composite exhibited the most efficient MB degradation removal rate and the reaction constant rate was 0.0412 min−1, which reached 3.62 and 2.08 times higher than that of pure PCN and BiVO4, respectively. EIS, i-t and PL measurements demonstrated that the 10-PCN/BiVO4 composite presented the smallest interfacial charge-transfer resistance and extraordinary photogenerated charge separation efficiency. The present study indicated that the synergistic effect of surface heterojunction of BiVO4 crystals and interface heterojunction between PCN and BiVO4 was conducive to facilitating the migration and separation of photogenerated charges, thus improving the photocatalytic degradation activity. [ABSTRACT FROM AUTHOR]

Because of their excellent insulation performance and processing properties, polymers are widely used in electrical and electronic applications. However, their further applications are severely constrained by their extremely low intrinsic thermal conductivity. Boron nitride (BN), which has high thermal conductivity and ideal insulation properties, is commonly used as a filler for improving the thermal conductivity of polymers. However, the high chemical inertia of the surface of BN makes it difficult to achieve an interconnection of BN sheets when building a three-dimensional (3D) BN skeleton in a polymer. In this study, urea melt pore preparation (UMPP) was used to fabricate a 3D BN skeleton. Urea was infiltrated into the BN skeleton to minimize the interfacial thermal resistance among the BN flakes and to join BNs. When the volume of a BN is 10 %, the thermal conductivity of the BN/epoxy composites is 3.15 W/(m·K). When the BN volume is 80 %, the thermal conductivity of BN/epoxy can reach 13.65 W/(m·K), which is 6500 % of pure epoxy resin. Additionally, the skeleton exhibits a remarkable mechanical strength capable of supporting weights up to 50,000 times its own, which facilitates easier handling and operation. The electrical resistivity volume of the UMPP composite is as high as that of the pure epoxy, whereas the dielectric loss is lower than that of pure epoxy. This study provides a new method for reducing internal interface thermal resistance of a skeleton formed by thermal conductive fillers with high chemical inertia such as boron nitride. [ABSTRACT FROM AUTHOR]

[AMIm]Cl@GNP/SBR composites were prepared by blending ionic liquid 1‐allyl‐3‐methylimidazolium chloride salt([AMIm]Cl) modified graphene nanoplatelets (GNP) and styrene‐butadiene rubber (SBR). The mechanical and thermal properties as well as the structure–activity relationship of the obtained composites based on the modified filler were investigated under the synergistic effect of non‐covalent and covalent bonding. The experimental results indicated that the modification of GNP by [AMIm]Cl occurred under mild conditions. The dispersibility of [AMIm]Cl@GNP in SBR was enhanced by its participation in vulcanization and the synergistic effect of non‐covalent and covalent cross‐linking networks such as cation‐π, π‐π, and hydrogen bonds. This improvement led to an increase in the interfacial bond strength of the composites and a reduction in the interfacial thermal resistance. These effects resulted in both reinforcement and thermal conductivity properties. The tensile strength and elongation at break of [AMIm]Cl@GNP/SBR composites increased from 18.2 to 22.9 MPa and from 737.9% to 923.5%, respectively, when the modification ratio of [AMIm]Cl was 1% and the loading of [AMIm]Cl@GNP was only 4 phr (mass ratio). At the same time, the thermal conductivity in the vertical direction of the composites increased from 0.25 to 0.44 W/(m·K), and the thermal conductivity in the horizontal direction increased from 0.27 to 0.81 W/(m·K). Highlights: Modified powder [AMIm]Cl@graphene nanoplatelets were prepared;[AMIm]Cl@graphene nanoplatelet/styrene‐butadiene rubber blend was prepared;Mechanical properties of blends significantly improved over blank;The horizontal thermal conductivity of the blends increases obviously;The vertical thermal conductivity of the blends was improved. [ABSTRACT FROM AUTHOR]

The corrosion resistance, conductivity, and cost of the metallic bipolar plates are the main limitations for the Proton Exchange Membrane Water Electrolysis (PEMWE) commercialization. In the present study, Ta, Nb, and Ti non-precious metallic coatings were deposited by closed-field unbalanced magnetron sputtering to increase the corrosion resistance and conductivity of titanium bipolar plates in PEMWE, respectively. The coating samples suffer from corrosion in a simulated extreme anode operating environment of PEMWE (0.5 M H 2 SO 4 + 5 ppm HF, 80 °C, O 2). The surface of the Ti coating forms the micropores due to the high dissolution rate in initial formation stage of the passivation film, resulting in a higher current density (1.41 × 10−6 A cm−2). The hydrolysis reaction of Ta coating causes the adsorption of sulfide ions, thereby affecting the density of the passivation film. Despite the Ta coating exhibiting a favorable current density (4.82 × 10−7 A cm−2), ICR (463.11 mΩ cm2) is lamentably poor. The surface of Nb coating has been completely covered by Nb 2 O 5 and NbO 2 in the simulated PEMWE environment. The reoxidation process of NbO 2 promotes the rate of passivation film formation and provides excellent conductivity. Therefore, Nb coating exhibits the lowest current density and interfacial contact resistance of 2.23 × 10−8 A cm−2 and 119.78 mΩ cm2, respectively, which is very low compared to the bare titanium bipolar plates. • The corrosion resistance and conductivity of three different metallic coatings (Nb, Ta, Ti) are investigated. • The corrosion mechanism of Ta and Nb coatings are revealed in a simulated PEM water electrolyzer environment. • The reoxidation process of NbO 2 promotes the rate of passivation film formation and provides excellent conductivity. [ABSTRACT FROM AUTHOR]

Halide solid electrolytes, known for their high ionic conductivity at room temperature and good oxidative stability, face notable challenges in all–solid–state Li–ion batteries (ASSBs), especially with unstable cathode/solid electrolyte (SE) interface and increasing interfacial resistance during cycling. In this work, we have developed an Al3+–doped, cation–disordered epitaxial nanolayer on the LiCoO2 surface by reacting it with an artificially constructed AlPO4 nanoshell; this lithium–deficient layer featuring a rock–salt–like phase effectively suppresses oxidative decomposition of Li3InCl6 electrolyte and stabilizes the cathode/SE interface at 4.5 V. The ASSBs with the halide electrolyte Li3InCl6 and a high–loading LiCoO2 cathode demonstrated high discharge capacity and long cycling life from 3 to 4.5 V. Our findings emphasize the importance of specialized cathode surface modification in preventing SE degradation and achieving stable cycling of halide–based ASSBs at high voltages. [ABSTRACT FROM AUTHOR]

The garnet‐type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) is a widely studied solid‐state electrolytes (SSEs) due to its high ionic conductivity and electrochemical stability. However, the conventional preparation process of LLZTO electrolyte tablets has encountered several issues such as powder embedment in the mold gaps and inadequate bonding between powders, leading to fragile electrolyte tablets that are prone to cracking. In this study, the effects of LLZTO electrolyte tablet pressing process parameters, including mixed powder content, polyvinyl alcohol (PVA) content and cold pressing pressure, on the electrochemical properties of button cells were investigated. The results indicated that the produced solid‐state electrolyte tablets with high quality, low interfacial resistance and low surface passivation layer (Li2CO3) content was obtained by using 0.8 g of mixed powder content, 0.7 g of PVA content and 20Mpa pressure. The interface resistance decreased from 2927.1 Ω to 1069.7 Ω under these conditions. Additionally, the Li symmetric cell treated with adhesive exhibited stable cycling for over 400 hours at 25 °C under a current density of 0.1 mA ⋅ cm−2. [ABSTRACT FROM AUTHOR]

Interfacial thermal resistance has often been attributed to the mismatch of phonon spectra between two materials and resulting phonon-interface scattering. However, we use the solution of Peierls–Boltzmann transport equation to reveal a substantial nonequilibrium thermal resistance across the interfaces of Si and SiGe alloys at room temperature, despite their nearly identical phonon dispersion and negligible phonon-interface scattering. The Kapitza length of the Si–Si0.99Ge0.01 interface is approximately 600 nm of Si. This originates from the mismatch in phonon distribution between Si and SiGe alloys due to their distinct scattering rates. The mismatch is relaxed by phonon scattering over a region of 1 μm around the interface, corresponding to the upper bound of mean free path Λ x of heat-carrying phonons. The relaxation process leads to the significant entropy generation and increased thermal resistance. Introducing a gradual variation in Ge concentration near the interface markedly reduces thermal resistance when implemented over the 1 μm period. Our finding demonstrates that the interfacial thermal resistance can be significant due to the nonequilibrium phonon distribution, even in the absence of phonon-interface scattering. In addition, among various phonon modes with a wide range of Λ x , the relaxation of the nonequilibrium is predominantly governed by the phonons with long Λ x . [ABSTRACT FROM AUTHOR]

The effective thermal characteristics of composite materials used in the theory of solid-state cooling are studied. Two classes of composites are considered: layered structures consisting of a large number of nano-sized layers and two-phase granular composites. It is assumed that the interfaces between media are imperfect. The Kapitza temperature jump occurs at the interfaces. The effective characteristics of layered structures are obtained using the matrix homogenization method. The homogenization of the characteristics of granular composites is based on the Bruggeman approach. Formulas taking into account the influence of the interlayer Kapitza resistance on the homogenized thermal characteristics of the structure are obtained. Expressions for average values of heat sources are derived. [ABSTRACT FROM AUTHOR]

While g‐C3N4 gains increasing attention as a polymeric semiconductor material for photo(electrochemical)applications, various strategies are deployed for enhancing the performance of g‐C3N4, among which heterojunction engineering remains the most preferred due to its high simplicity and efficiency. This work uses a facile wet impregnation to obtain a synergistic g‐C3N4/CuO heterojunction with reduced interfacial resistance. Maximum performance is exhibited at a CuO loading of 5% (by weight). The photocatalytic efficiency can be established by assessing ciprofloxacin degradation under visible light irradiation. A photocurrent density of −3.5 mA cm−2 at −0.67 V is observed when the material is used as a photocathode in a neutral medium, and integration with g‐C3N4 can address the stability issues associated with bare CuO photocathodes. [ABSTRACT FROM AUTHOR]

The current commercially used anode material, graphite, has a theoretical capacity of only 372 mAh/g, leading to a relatively low energy density. Lithium (Li) metal is a promising candidate as an anode for enhancing energy density; however, challenges related to safety and performance arise due to Li's dendritic growth, which needs to be addressed. Owing to these critical issues in Li metal batteries, all-solid-state lithium-ion batteries (ASSLIBs) have attracted considerable interest due to their superior energy density and enhanced safety features. Among the key components of ASSLIBs, solid-state electrolytes (SSEs) play a vital role in determining their overall performance. Various types of SSEs, including sulfides, oxides, and polymers, have been extensively investigated for Li metal anodes. Sulfide SSEs have demonstrated high ion conductivity; however, dendrite formation and a limited electrochemical window hinder the commercialization of ASSLIBs due to safety concerns. Conversely, oxide SSEs exhibit a wide electrochemical window, but compatibility issues with Li metal lead to interfacial resistance problems. Polymer SSEs have the advantage of flexibility; however their limited ion conductivity poses challenges for commercialization. This review aims to provide an overview of the distinctive characteristics and inherent challenges associated with each SSE type for Li metal anodes while also proposing potential pathways for future enhancements based on prior research findings. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) have attracted great interest due to their promising energy density and strong safety. However, the interface issues, including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes, have restricted the development of high-voltage ASSLBs. Herein, we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li64La3Zr14Ta0.6O12 (LLZTO)–cathode interfaces. The polymer can perfectly fill the voids and create a stable interface contact between LLZTO and cathodes. In addition, the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte (SPE), which facilitates the electrochemical stability with high-voltage cathode. The all-solid-state Li∣LLZTO-SPE∣LiFe0.4Mn0.6PO4 (LMFP) cells achieve a low interface impedance, high specific capacity, and excellent cycling performance. This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs. [ABSTRACT FROM AUTHOR]