In proton exchange membrane fuel cells(PEMFC), carbon paper is demanded to possess robust mechanical strength, high electrical and thermal conductivity, and optimized porosity for gas/water transportation. Conventional materials frequently fall short of meeting these requirements. Herein, multi-walled carbon nanotubes (MWCNTs) were integrated into the carbon paper by pre-impregnation to enwrap carbon fibers, thereby enhancing the fiber-resin bonding and mechanical properties of the carbon paper. Simultaneously, the MWCNTs form additional branching networks within the conductive and thermal skeleton established by the carbon fibers, strengthening both electrical and thermal pathways. At an optimal MWCNTs impregnation concentration of 3 wt %, the modified carbon paper achieved tensile and flexural strengths of 26.54 MPa (a 38.2 % increase) and 25.12 MPa (a 289.5 % increase), respectively, compared to conventional carbon paper (19.21 MPa, 6.45 MPa). Its in-plane and through-plane thermal conductivities improved to 19.14 W/(m center dot K) and 0.81 W/(m center dot K), surpassing conventional values (12.96 W/(m center dot K), 0.11 W/(m center dot K)). PEMFC simulations confirmed that the enhanced thermal conductivity reduces the peak operating temperature and improves temperature uniformity across the membrane. The modified carbon paper also exhibited lower resistivity (5.8 m Omega center dot cm) and increased the peak power density of the fuel cell by 112.9 % (1255.9 vs. 589.8 mW/cm2). These advancements enhance the efficiency, stability, and lifespan of the fuel cell, demonstrating significant application potential in the practical fuel cells systems.

As electronics shrink and power density rises, effective heat dissipation becomes critical. Thermal interface materials (TIMs) are vital for ensuring the reliability and sustainable operation of next-generation devices. Conventional research typically prioritizes high thermal conductivity as the primary objective. However, the thickness, compressibility, and deformability of TIMs also critically influence heat transfer performance. Here, a novel strategy is reported for fabricating an ultralight 3D porous graphene TIM with high compressibility and low thermal resistance via pore structure control achieved by regulating pressure during foaming. The prepared reduced graphene oxide (rGO) foam combines ultrahigh compressibility (94.85%) and low density with low thermal resistance (0.151 cm2 center dot K/W under 100 psi) and excellent in-plane temperature uniformity performance, while offering superior conformability to complex mating interfaces. A significant reduction in chip temperature (8.83-13.3 degrees C) is achieved compared to commercial thermal pads (5 W/mK) at heat dissipation powers of 20-30 W. Furthermore, the manufacturability of these TIMs showcases a promising new approach to TIM fabrication for next-generation, high-power-density electronic devices.

The field of flexible electronics has flourished in recent years. Among its key elements, the flexible printed circuit (FPC) stands out as a fundamental building block, forming a circuit system. However, as power density continues to increase, issues related to heat dissipation and electromagnetic interference become increasingly prominent. Together, these factors pose growing challenges to the reliability of FPCs. In this paper, we introduce a method for preparing a flexible printed circuit using hexagonal boron nitride (h-BN) and polyurethane (PU). The resulting h-BN/PU-based flexible printed circuit (hBP-FPC) achieves high thermal conductivity, low dielectric loss, and robust bending resistance. The BN filler endows hBP-FPC with significant thermal conductivity anisotropy. The in-plane thermal conductivity of the prepared hBP-FPC material reaches 4.1 W (m K)-1, and the cross-plane thermal conductivity is 1.4 W (m K)-1. A significant temperature reduction (7.1-19.2 degrees C) is achieved in the hBP-FPC compared to commercial FPC over the power density range of 0.125-0.375 W/cm2. This study provides a promising strategy for developing high-performance substrates for next-generation high-power-density flexible electronics.

As the primary gas diffusion layer (GDL) substrate in proton exchange membrane fuel cells (PEMFCs), carbon paper must provide mechanical support, efficient thermal and electrical conduction, and effective mass transport. However, conventional carbon paper often exhibits limited mechanical strength and inadequate electrical and thermal conductivities, which restricts overall cell performance, ultimately making modification essential. Herein, we fabricated a modified carbon paper consisting of an interwoven skeleton of mesophase pitch-based carbon fibers (MPCFs) and polyacrylonitrile-based carbon fibers (PAN-CFs), with graphite nanoplates (GNPs) anchored onto the fiber surfaces. The hybrid carbon felt was prepared by rapid filtration, in which MPCFs bridged adjacent PAN-CFs or penetrated vertically into interlayer voids, establishing additional pathways that enhanced both electrical and thermal conduction. GNPs were subsequently introduced through impregnation with a GNP dispersion, adhering to both fiber types and forming nanoscale protrusions. These protrusions increased fiber surface roughness, strengthened the fiber/resin carbon interface, and improved the mechanical properties of the carbon paper. Moreover, GNPs filled interstitial voids within the skeleton, forming finer branched networks that further augmented electrical and thermal conductivity. When loaded with 24 g/m2 of MPCFs and impregnated with a 2 wt% GNP dispersion, the modified carbon paper exhibited a flexural strength of 22.91 MPa and a tensile strength of 25.99 MPa, representing increases of 67 % and 89 %, respectively, over the unmodified material. The in-plane and through-plane thermal conductivities reached 37.09 W/(m center dot K) and 8.83 W/(m center dot K), respectively, while the in-plane electrical resistivity was reduced to 3.74 mS2 cm. These values signify a notable improvement compared to the unmodified carbon paper, which exhibited an in-plane thermal conductivity of 12.20 W/(m center dot K), through-plane thermal conductivity of 0.04 W/(m center dot K), and in-plane electrical resistivity of 8.80 mS2 cm. In fuel cell tests, the modified carbon paper achieved a peak power density of 1.33 W/cm2, outperforming the unmodified reference by 125 %. This work demonstrates a synergistic modification strategy using MPCFs and GNPs to simultaneously enhance the mechanical, thermal, and electrical properties of carbon paper. The proposed approach offers a promising pathway toward developing high-performance GDLs for advanced PEMFC applications.

Low-temperature environments substantially degrade lithium-ion battery performance, underscoring the need for efficient heating strategies. Carbon-based heating films offer considerable potential for vehicular low-temperature thermal management due to their favorable material properties, yet research has largely centered on feasibility rather than on key influencing factors or heating-induced long-term degradation. This study systematically evaluates three critical factors governing the performance of carbon-film-based heating methods and compares the short- and long-term effects of four vehicle-representative heating configurations. In short-term tests, the double-sided external heating configuration achieves charging efficiency more than twice that of the unheated battery, while the double-sided composite self-heating configuration provides superior capacity enhancement of up to 77%. Long-term cycling results show that double-sided external heating induces minimal capacity fade, whereas single-sided composite self-heating produces more significant degradation and structural damage. Overall, the findings highlight the distinct advantages of each heating configuration under low-temperature conditions and emphasize the importance of aligning heating architecture with operational requirements for safe and efficient battery heating. This work establishes an integrated framework for selecting short- and long-term heating strategies across diverse low-temperature scenarios and provides a comprehensive evaluation of their performance and degradation pathways.

In this work, we fabricated the graphite nanoplatelets (GNPs)-based thermal conductive materials (TCMs) via the gap-coating method. Remarkably, the TCMs have a prominent heat conduction coefficient of 36.44 W/mK, which is attributed to the aligned graphite nanoplatelets. Viscosity is a key factor for the alignment of the fabricated composite. Polarized Raman spectroscopy was performed on the transverse sections of the composite to detect the orientation degree, and the intensity of the 2D Raman peak is sensitive to these anisotropic properties. Furthermore, Polarized Raman spectroscopy is initially employed for calculating interfacial thermal resistance (ITR) in samples with different viscosities. The orientation factors were 0.35 and 0.23, while the ITR values were 5.20 x 10-6 m2 K W- 1 and 5.91 x 10-6 m2 K W- 1 respectively. These values correspond to an increase in viscosity from 223 mPa center dot s to 559 mPa center dot s, confirming the effect of viscosity on both orientation degree and interfacial thermal resistance. This approach also provides a promising new method for detailed ITR determination in well-dispersed thermal conductive materials.

Microporous layers (MPLs) play a pivotal role in proton exchange membrane fuel cells (PEMFCs) by regulating water management and reactant transport. However, conventional MPLs with single-sized pores lack the structural versatility to simultaneously meet the requirements for efficient gas transport and water removal, which severely limits the performance improvement of PEMFCs. This study fabricates an MPL with a graded pore structure through solvent-controlled differentiation and a stepwise coating-sintering process, which synergistically enhances capillary-driven gas supply and liquid water removal. Multiphysics simulations confirm that the gradient structure improves water drainage and gas diffusion, and this improvement is reflected in the superior performance of the graded MPL compared with conventional single-layer structures under varying backpressure conditions. The MPL with a graded pore structure exhibits the highest output performance of 1860 mW cm-2 under hydrogen/air operation at a high relative humidity of 100%, representing an improvement of approximately 36.8% over the commercial MPL, and still delivers a 10.4% enhancement under 75% relative humidity. The notable performance gains achieved underscore the practical potential of the fabrication method, while our findings establish critical structure-transport correlations for MPL optimization in advanced PEMFCs.

Enhancing the overall performance of lead-free solders remains a critical challenge in materials engineering. In this study, composite solders were fabricated by incorporating nano-sized silicon carbide (SiC) particles (0.3-1 wt.%) into Sn58Bi eutectic powder to refine the microstructure and enhance the mechanical properties of solder joints. The effects of SiC nanoparticle addition on the wettability and mechanical behavior of the Sn-58Bi eutectic alloy were systematically investigated. The shear strength and interfacial evolution of the SnBi-SiC/Cu joints under multiple reflow cycles were characterized.

Silicon nitride (Si3N4) and copper (Cu) were brazed using Ag-Cu-Ti filler alloys to investigate the effects of brazing parameters on the evolution of interfacial microstructure and mechanical performance. The typical interfacial microstructure was Cu/Cu(Ag) solid solution/eutectic alloy with CuTi precipitates/Ti5Si3/TiN/ beta-Si3N4. Ti5Si3 nucleated on TiN before developing into discrete clusters that eventually connected to create a near-continuous layer. Increasing the brazing temperature and Ti content in the filler alloy initially enhanced the thickness of the reaction layer, resulting in improved joint strength. However, beyond a certain threshold, the thickness reached saturation, and the shear strength began to decline. Ti-promoted interdiffusion between the Ag and Cu substrates accelerated the plasticity loss of the filler alloy. At 930 degrees C, the formation of a brittle CuTi/Ag composite layer further compromised joint strength. Additionally, prolonged holding times degraded shear strength due to excessive thickening of the reaction layer and the development of an extended penetration zone, both of which elevated interfacial stresses. Optimal joint performance was achieved at 840 degrees C using AgCu-2Ti filler with a 10 min holding time, resulting in a maximum shear strength of 37 MPa through balanced interfacial reaction control and minimal formation of detrimental phases.

Wearable heaters are essential for people living in cold regions, but creating heaters that are low-cost, lightweight, and high air permeability poses challenges. In this study, we developed a wearable heater using carbon nanotube/water polyurethane (CNT/WPU) nanocomposite fibers that achieve high extension rate and conductivity. We produced low-cost and mass-produced fibers using the wet spinning. With heat treatment, we increased the elongation rate of the fibers to 1893.8% and decreased the resistivity to 0.07 omega*m. then wove the fibers into a heating fabric using warp knitting, that resistance is 493 omega. Achieved a uniform temperature of 58 degrees C at voltage of 36 V, with a thermal stability fluctuation of -5.0 degrees C to +6.3 degrees C when bent from 0 degrees to 360 degrees. Our results show that wearable heaters have excellent flexibility and stretchability, due to nanocomposite fibers and special braided structure, which offer a novel idea for wearable heaters.

Stretchable conductors (SCs) have shown promising potential in the field of stretchable electronic devices for their lightweight, high flexibility, stable performance, and easy integration. However, the conductivity of most reported stretchable conductive composites is sensitive to deformation, and it is still unsatisfactory due to their poor recoverability and low reliability under large strain. In this paper, we have fabricated a serpentine stretchable conductor (SSC) with high conductivity, stretchability, and ultra-stability by spontaneously wrapping elastic waterborne polyurethane (WPU) sheath on the surface of the multi-walled carbon nanotube (MWCNT)/ WPU nanocomposite conductive yarn, which was prepared by a simple wet-spinning method. The WPU elastic sheath endows SSC with long-term tensile durability and recoverability. Remarkably, benefiting from the sharing effect of the serpentine structure on the tensile strain energy, SSC shows distinctive strain-insensitive behavior (Delta R/R0 less than 1.6%) up to 100% strain and ultra-high quality factor (Q = 105) at 80% strain. Furthermore, SSC also has temperature resistance, waterproof ability, and self-healing capability, making it capable of being used in harsh circumstances. The combination of high conductivity, stretchability, and super reliability renders many potential applications for SSC, such as stretchable interconnects and wearable heaters. Such serpentine stretchable device with distinctive strain-insensitive behavior provides a novel design idea for stretchy electronics.

Hexagonal BCN (h-BCN) is considered to be a promising dielectric ceramic material with a hybrid B-C-N structure and an electromagnetic wave (EMW) absorbing material with tenable properties. H-BCN bulk and microtube architectures are simultaneously synthesized by precursor pyrolysis method using BCl3, aniline (AN) and diethylenetriamine (DETA) as the raw material. By analyzing its electromagnetic parameters, the effective absorption bandwidth of the sample cracking at 900 degrees C with the proportion of raw materials (DETA:AN = 1:1) can be up to 7.2 GHz, and the minimum reflection loss can reach -43.6 dB at 7.92 GHz with a thickness of 3.5 mm. Moreover, the EMW absorbing property of the ceramic can be tuned by adjusting the ratio of monomers, pyrolysis temperature, and cooling rates.

Black phosphorus has important applications in many fields such as optics, optoelectronics and thermals. Many of its excellent properties are related to its special anisotropy. In this work, we adopted Raman spectroscopy, which can obtain fast response optical signals without destroying the structure of the sample, to identify its crystal orientation and explore its thermal and SERS properties. We successfully distinguished the armchair and zigzag directions of black phosphorus by angle-resolved polarized Raman spectroscopy of Ag mode in a less studied orthogonal polarization configuration. Then we used temperature dependent Raman spectroscopy to study its thermal properties. It is found that the first order temperature coefficients of its three Raman vibration modes Ag1, B2g, and Ag2 are -0.0133 cm-1 K-1, -0.0232 cm-1 K-1 and -0.0229 cm-1 K-1, respectively for the 3.2 nm sample. Furthermore, we studied the surface enhancement effect of black phosphorus with different thicknesses as SERS substrates. We found that few-layer black phosphorus has better enhancement effects and its limit of detection for MB and CV are both 10-6M. The analytical enhancement factor of black phosphorus substrates on CV can achieve 1.2 × 103 by calculation. These methods can be extended to other similar two-dimensional materials.

In recent years, artificial muscle is of great research interest due to its promising application. However, low deformation, complicated fabrication process, and high cost hinder their development. Herein, electro-thermally driven biaxial bending artificial muscle based on oriented graphite nanoplate nanocomposite (GN)/polyimide (PI) complex structure is successfully fabricated by cost-effective process utilizing coefficient of thermal expansion difference between them. GN/PI bi-layer films were further assembled and packaged into multi-unit biaxial bending actuator, which could extend and contract like artificial muscle. The unique characteristics of large deformation, easy control, low cost and simple fabrication process distinguish the GN/PI bi-layer based artificial muscle from others. Driven by the voltage of 10 V, the artificial muscle could reversibly reach a shrinkage rate of 11% and a maximum lifting height of 2.5 cm with the object weight of 5.0 g. Moreover, a walking robot has also been designed to achieve a large displacement.

Electrothermal materials have been widely used due to controllable heat energy in our life. With the development of wearable technology, a flexible, safe and waterproof heater with the good ability to endure repeated bending is required in future. In this paper, we have developed a novel wearable heater based on flexible, stretchable graphite nanoplates and polyurethane (GNP/PU) nanocomposite films. Firstly, the GNP/PU thin films with a thickness of 30-200 mu m were fabricated in mass production by the method of gap-coating, which can be bent 180 degrees repeatedly, or even knotted for their excellent flexibility, and has a maximum elongation up to 387.8%, due to the homogenous distribution of GNP in PU matrix. By the control on the amount of GNP and the thickness of the film, the minimum resistivity and square resistance of the GNP/PU films can be 80 m Omega.cm and 4 Omega/square, respectively. Through a further flexible structure designing and waterproof electronic packaging process, the fabricated wearable heaters are able to withstand 100,000 180-degrees bending with the resistance changes of only 3.24%, and have a IPX7 waterproof ability to work continuously for 120 min under 1.30 m water. Interestingly, as-prepared bare GNP/PU films have a good resistence to water and salt erosion, with the light 2.1%, 2.4% and 3.1% increasing in electrical resistance, and without obvious change in heating performance, even after the immersion in pure water, 0.5% and 5% salt water and dried completely. Furthermore, the wearable heaters can generate heat uniformly under the safe voltage of 5-24 V to achieve rapid heating and cooling rate of 25 degrees C/min and 13 degrees C/min, respectively. Lastly, a heating full-body vest mode of as-prepared wearable heaters was fabricated, which can work well with hand raising, bending and walking. The results showed that as-prepared wearable heaters were very suitable for wearable electronics, due to the excellent flexibility and stretchability of GNP/PU films and their special packaging structure, which provides a new choice for wearable heating products.

High efficiency and broad bandwidth wave absorption materials are urgent need in daily life for human health. Carbon material (graphene, etc.) is widely used in electromagnetic wave (EMW) absorption field for light weight, high surface area, and excellent electrical conductivity. However, the immoderate conductivity of the carbon will also cause the impedance mismatch and need more consideration. We have synthesized sucrose-derived carbon-based hybrid absorbers, and a series of Ni-based alloys (Ni, Fe–Ni, Co–Ni) are decorated on the surface of the carbon. Consequently, the Ni/C composite shows a maximum attenuation constant, and an ultra-broad wide effective bandwidth of 6.24 GHz with an optimal reflection loss (RL) value of − 20.5 dB located at thickness of only 1.7 mm. The Co–Ni/C composite has an improved impedance matching level, and shows the optimal RL of − 34.3 dB located at a thickness of 3.3 mm with an effective bandwidth of 4.24 GHz. The Fe–Ni/C composite shows an optimal RL among all the samples of − 42.3 dB located at a thickness of 5.7 mm with the effective bandwidth of 2.8 GHz. The Ni-based alloys decorated sucrose-derived carbon hybrid can be a proper candidate for microwave absorption as its light-weight outstanding EMW absorption property. The Ni-based alloys decorated sucrose-derived carbon hybrid for microwave absorption

Since the "net-zero " goal was proposed, wind power has been developed rapidly in recent years. Due to its largescale installations in cold regions, the icing of wind turbine blades is currently one of the main limitations for efficient operation. In response to this issue, a highly reliable, flexible, stretchable, and lightweight in-situ deicing heating system based on the CNT/WPU nanocomposite films was developed. The CNT/WPU thin films were fabricated by the roll-to-roll gap-coating and hot-pressing process leading to as-prepared CNT/WPU film heaters have so outstanding reliability that they can withstand 100,000 times 240 bending with the resistance fluctuation of 3.17 %, and the repeated stretching of 2.0 % strain in the length direction without any impact on their temperature distribution, and even the weak impact with 10 % strain. The films may have promising potential applications in various curved surface heating with strict requirements on reliability in the future.

Desired to improve the capacity and cycle stability of lithium sulfur batteries, it is urgent to solve the insulating nature of sulfur cathode, sluggish electrochemical kinetics, and severe shuttle effect associated with polysulfide intermediates. Here single manganese (Mn) atoms implanted in oxygen and nitrogen double-doped hollow carbon sphere frameworks (Mn/C-(N, O)) are prepared as electrocatalyst and anchoring sites for lithium sulfur batteries. O, N-coordinated single Mn atoms can rich in atomic active sites, anchor polysulfides through strong Lewis acid-base interactions. Meanwhile, Mn cofactors show high catalytic activity on the conversion reaction of polysulfides. Moreover, the abundant pores in conductive carbon frameworks can facilitate electrolyte diffusion while simultaneously promote the dynamic protection of the cathode structure during cycling. Consequently, S@Mn/C-(N, O) exhibits an excellent cycling stability with an initial capacity of similar to 900 mAh g(-1) at 1 C with only 0.05% capacity decay per cycle after 1000 cycles. The theoretical simulation results and the enhanced electrochemical performance show the important role of single atom in accelerating polysulfides transformation and suppressing the "shuttle effect".

CoCO 3 with high theoretical capacity has been considered as a candidate anode for the next generation of lithium-ion batteries (LIBs). However, the electrochemical performance of CoCO 3 itself, especially the cyclic stability at high current density, hinders its application. Herein, pure phase CoCO 3 particles with different particle and pore sizes were prepared by adjusting the solvents (diethylene glycol, ethylene glycol, and deionized water). Among them, CoCO 3 synthesized with diethylene glycol (DG-CC) as the solvent shows the best electrochemical performance owing to the smaller particle size and abundant mesoporous structure to maintain robust structural stability. A high specific capacity of 690.7 mAh/g after 1000 cycles was achieved, and an excellent capacity retention was presented. The capacity was contributed by diverse electrochemical reactions and the impedance of DG-CC under different cycles was further compared. Those results provide an important reference for the structural design and stable cycle performance of pure CoCO 3 .

The large capacity fading and short lifespan of SnO2-based anodes originate from the serious coarsening of Sn nanoparticles caused by structural reorganization of SnO2 during repeated cycling. Herein, a hybrid structure composed of SnO2 supported on orderly stacked graphene sheets (SnO2@OS-rGO) is constructed by freeze casting method to address the above issues. The orderly stacked graphene anchors SnO2 firmly depending on the 7C-7C interactions, thus improves the discharge capacity and cycling stability of SnO2. Besides, the ordered graphene promotes the reaction kinetics of SnO2@OS-rGO by shorten the transmission path of lithium ions. As a result, the obtained SnO2@OS-rGO delivers an unconventional discharge capacity up to 1080 mAh g(-1) at 0.2 A g(-1) for over 500 cycles, which increased by similar to 200% compared with the 1st cycle. The gradually increasing capacity originates from the improvement of the conversion reaction. This study provides a new strategy for developing long cycle stable SnO2 anodes by introducing orderly stacked graphene.