The research, published in the journal Advanced Composites and Hybrid Materials, was led by Nayeong Kim and Inseok Baek, who contributed equally, along with colleagues at the Korea Institute of Materials Science in Changwon, Pusan National University, and Oak Ridge National Laboratory in Tennessee. Corresponding authors Youngseok Oh and Jinsu Kim of KIMS guided the study, which was supported by the National Research Foundation of Korea and the Korea Institute of Materials Science, with additional authorship under the U.S. Department of Energy’s contract with UT-Battelle at Oak Ridge. The work addresses a fundamental tension in induction welding of carbon fiber-reinforced thermoplastics, known as CFRTPs: effective joining demands both a rapid temperature rise at the weld line and a temperature field that is spatially uniform across the entire bond area.

The difficulty stems from the physics of induction heating itself. When an alternating magnetic field passes through an electrically conductive material, it induces eddy currents that dissipate energy as Joule heat. In a carbon fiber composite, however, the conductive network is formed by fibers that may not create continuous current loops in the right places, and the magnetic field generated by the induction coil is inherently non-uniform, strongest near the coil and weaker farther away. The result is localized hot spots and cold zones, which translate directly into incomplete melting, poor polymer impregnation, and weak welds. Achieving both rapid heating and uniform heating simultaneously has therefore been a persistent challenge, because the strategies that accelerate heating often intensify the non-uniformity.

The Korean-American team’s answer is a synergistic heating medium: a powdered aerogel composed of carbon nanotubes, iron oxide (Fe3O4) nanoparticles, and polyamide 6. Each component plays a distinct role. The carbon nanotubes form continuous conductive pathways throughout the aerogel, enabling efficient Joule heating when eddy currents are induced, and they also improve heat transfer through the weld interface. The Fe3O4 particles, meanwhile, respond rapidly to the alternating magnetic field through magnetic loss mechanisms, including hysteresis loss, acting as countless nanoscale heat sources distributed throughout the material. Because these magnetic heat sources are dispersed rather than concentrated, they compensate for the non-uniformity of the external field, warming regions that eddy-current heating alone would leave cold.

The aerogel architecture is central to the design. Aerogels are ultralight, highly porous solids, and in this powdered form the nanocomposite can be sprinkled or placed at the weld interface between two CFRTP parts. The porosity and the interconnected CNT network maximize the material’s interaction with the electromagnetic field while allowing the molten polymer to flow and impregnate the layer during welding. Crucially, the carbon nanotubes do more than generate heat: they also act as nanoscale mechanical pins that bridge the two composite surfaces, reinforcing the joint at the molecular level and enhancing interfacial weld strength beyond what thermal fusion alone can achieve.

The researchers fabricated nanocomposites with varying ratios of CNTs to Fe3O4 and experimentally identified the optimal composition, systematically balancing electrical conductivity against magnetic loss. The performance gains were striking. The nanocomposite-enabled welding system exhibited an initial heating rate of 148.7 degrees Celsius per second, which is 94.6 percent higher than that achieved with carbon fiber composite alone. That figure demonstrates that the dual heating mechanism does not merely redistribute heat; it dramatically accelerates the entire process, a property that matters enormously in industrial settings where cycle time determines economic viability.

Speed, however, would mean little without joint quality, and here too the results were compelling. The interfacial shear strength of welds made with the nanocomposite interlayer increased by 30.8 percent compared with conventional induction welding. Fracture-surface analysis of the broken joints revealed why: the weld areas showed more uniform melting and more effective impregnation of the polymer across the full bond area, rather than the patchy fusion characteristic of overheated-and-underheated regions. In a well-made thermoplastic weld, the polymer chains from each surface interdiffuse and entangle as the interface melts; uniform melting maximizes the area over which this healing occurs, and the CNT pinning adds mechanical interlocking on top.

The implications for manufacturing are considerable. Thermoplastic composites are prized because, unlike thermoset composites, they can be remelted, reshaped, and welded, opening the door to faster production of aircraft structures, automotive body panels, battery enclosures, and hydrogen storage vessels. Induction welding is already used to join thermoplastic aircraft components, but its reliability has been limited by temperature non-uniformity, forcing manufacturers to weld slowly or accept weaker joints. A consumable interlayer material that guarantees rapid, even heating could reduce energy consumption, shorten cycle times, and improve the structural integrity of welded assemblies, all without requiring changes to the induction equipment itself.

The study also highlights a broader trend in materials science: the deliberate combination of multiple physical mechanisms within a single nanostructured material to overcome the limitations of each. Joule heating and magnetic loss heating are complementary responses to the same electromagnetic field, and by embedding both in one aerogel, the researchers created a system in which the weaknesses of one mechanism are offset by the strengths of the other. The mechanical reinforcement provided by the CNT network is a bonus that no purely thermal approach could offer. The authors suggest that this nanocomposite represents a promising strategy for achieving both rapid and spatially uniform interfacial heating, leading to improved mechanical performance in the induction welding of CFRTPs.

Published as an open-access article on 2 September 2026, the paper invites further exploration of composition optimization, scalability of aerogel production, and long-term durability of the welded joints under fatigue and environmental exposure. For now, it stands as a vivid demonstration that sometimes the key to a better industrial process is not a new machine but a smarter material placed precisely where it is needed, a whisper-thin layer of nanotubes and magnetic particles that turns a patchy, uneven weld into a fast, strong, and uniform bond.

Subject of Research: Nanocomposite aerogel interlayers for rapid and uniform induction welding of carbon fiber-reinforced thermoplastic composites

Article Title: Synergistic heating effect via CNT/Fe3O4 nanocomposite aerogels enabling uniform and rapid induction welding with high bond strength in CFRTPs

Article References: Kim, N., Baek, I., Park, B., Kim, D., Jeong, C., Lee, J., Kim, J.-S., Joo, G., Kim, S., Kumar, V., Oh, Y., & Kim, J. (2026). Synergistic heating effect via CNT/Fe3O4 nanocomposite aerogels enabling uniform and rapid induction welding with high bond strength in CFRTPs. Advanced Composites and Hybrid Materials. https://doi.org/10.1007/s42114-026-02040-x

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02040-x

Keywords: induction welding, CFRTP, carbon nanotubes, Fe3O4, nanocomposite aerogel, Joule heating, magnetic loss, hysteresis loss, interfacial shear strength, thermoplastic composites, polyamide 6, aerogels

Phase change materials are deceptively simple in concept. When a paraffin wax, a salt hydrate, or a polyethylene glycol melts, it absorbs a large quantity of latent heat at a nearly constant temperature; when it solidifies again, that heat is released. This makes PCMs ideal for banking thermal energy and for passively regulating temperature in buildings, electronics, and batteries. Yet the classic formulations suffer from three chronic weaknesses. First, once molten, they leak, which means they must be contained or encapsulated before they can be deployed. Second, most organic PCMs conduct heat poorly, so charging and discharging the store is slow and temperature gradients build up inside the material. Third, conventional PCMs merely store heat; they do not convert other forms of energy into it, limiting their usefulness in systems that need to harvest sunlight or electricity directly.

MXenes, first reported in 2011 when researchers exfoliated the layered ceramic Ti3AlC2 into two-dimensional titanium carbide sheets, have rapidly become one of the most versatile nanomaterial platforms in materials science. These transition metal carbides and nitrides carry a chemically tunable surface terminated with functional groups, and they combine metallic electrical conductivity with strong in-plane thermal transport. The review emphasizes that this combination is precisely what leaky, sluggish PCMs need. Dispersed or structured within a phase change matrix, MXene nanosheets act simultaneously as a thermal bridge that accelerates heat distribution, an absorbent scaffold that locks the molten PCM in place by capillary forces and surface interactions, and in many designs as the actual energy converter that turns sunlight or electricity into stored heat.

The authors devote considerable attention to how these composites are made, beginning with MXene synthesis itself. The dominant route remains selective etching of the aluminum layers from MAX phase precursors, typically using hydrofluoric acid or gentler fluoride salt mixtures such as hydrochloric acid combined with lithium fluoride, followed by delamination into single-layer sheets. Newer protocols, including electrochemical etching, dry selective extraction guided by computation, and even ultrafast laser synthesis of MAX phases, are expanding the toolkit and reducing the environmental burden of the fluoride chemistry. The review notes that etching conditions directly control the surface terminations, defect density, and flake size of the resulting MXene, which in turn govern how well the nanosheets disperse in a PCM, how strongly they bind the melt, and how efficiently they conduct heat through the composite.

Encapsulation strategies form the second pillar of the review. The simplest approach is the form-stable composite, in which a porous MXene aerogel or hydrogel-derived framework is infiltrated with molten paraffin or polyethylene glycol, producing a monolith that holds its shape even above the melting point. Binderless MXene aerogels assembled without polymeric binders have achieved ultrahigh energy storage densities alongside exceptional electromagnetic interference shielding, a bonus property that stems from the electrical conductivity of the percolating nanosheet network. Hybrid frameworks that pair MXene with graphene or with copper nanowires exploit synergistic conduction pathways, while polymer partners such as polyvinyl alcohol, gelatin, cellulose nanofibers, and polyurethane add mechanical flexibility, producing composite films that can be bent, wrapped around pipes, or integrated into fabrics. Microencapsulation, in which PCM droplets are shelled in silica or polymer with MXene incorporated into the shell or coating, offers another route to leakage-proof, supercooling-suppressed particles suitable for slurries and coatings.

Solar photothermal conversion is where MXene composites deliver their most eye-catching performance. Broad absorption across the solar spectrum, combined with efficient conversion of absorbed photons into heat, allows MXene-loaded PCMs to charge rapidly under illumination. Paraffin infiltrated into Ti3C2Tx MXene and gelatin aerogels, MXene aerogel monoliths, diatomite ceramics coated with MXene, kapok fibers modified with the nanosheets, and composites decorated with gold nanorods or nano copper have all demonstrated high solar-thermal conversion efficiencies and strong shape stability. The review highlights designs that pair MXene with polydopamine for synergistic photothermal enhancement, with biochar from sorghum straw for sustainable scaffolds, and with liquid metal gallium modified on blackbody-inspired principles, extending the concept to interfacial evaporation and desalination where stored heat drives water purification after sunset.

Electrothermal applications form a complementary frontier. Because MXenes conduct electricity, a composite PCM can be charged simply by passing current through it, converting electrical energy into latent heat with near-total efficiency. Flexible films based on polyethylene glycol with two-dimensional MXene, aramid nanofiber composites, cellulose nanofiber materials, and sandwich-structured MXene and polyvinyl alcohol systems with barium sulfate have demonstrated dual-mode solar and electrothermal charging. Such films are candidates for wearable thermal management, defrosting surfaces, and electrically rechargeable heat packs, and the review notes that molecular dynamics studies of lauric acid in polylactic acid and MXene matrices are now providing atomistic insight into how the filler alters crystallization and heat transport.

Perhaps the most consequential application is thermal safety in batteries and electronics. Lithium-ion cells can enter catastrophic thermal runaway when heat accumulates faster than it is removed, and the review cites extensive work on MXene-based composite PCMs for passive battery cooling. Composites pairing MXene with carbon nanotubes, expanded graphite, hexagonal boron nitride nanosheets for electrical insulation, or VO2 for thermally triggered tunable conductivity can absorb heat spikes during fast charging or high discharge, delay the onset of runaway, and in flame-retardant formulations actively suppress fire propagation. Similar composites protect power electronics and LED systems, and some add electromagnetic interference shielding and even radiation protection, turning a simple heat sink into a multifunctional protective layer.

The review closes with a candid assessment of obstacles and a striking glimpse of the future. MXenes are vulnerable to oxidative degradation, which erodes their conductivity over time, and surface and edge passivation strategies are being developed to extend operational lifetimes. Large-scale, low-cost synthesis remains a hurdle, as does the long-term cycling stability of composites exposed to repeated melting. Yet the authors see these materials converging toward integrated platforms that convert, store, and manage energy in a single component: fabrics that harvest sunlight by day, warm the wearer at night, and hide the wearer’s infrared signature; battery packs that cool themselves and shield electronics; and building panels that smooth the intermittency of renewable power. Infrared camouflage, achieved by tuning emissivity and buffering surface temperature with phase change layers, illustrates how far the concept has traveled from simple heat storage. For a field racing to decarbonize, MXene-based composite PCMs, the review concludes, offer a rare combination of high latent heat, fast charging, and multifunctional intelligence that could define the next generation of thermal energy technologies.

Subject of Research: MXene-based composite phase change materials for thermal energy storage and management

Article Title: Review: MXene-based composite phase change materials for preparation, encapsulation, and thermal management

Article References: Wu, Y., Huang, Y., & Li, L. (2026). Review: MXene-based composite phase change materials for preparation, encapsulation, and thermal management. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13844-z

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13844-z

Keywords: MXene, phase change materials, thermal energy storage, encapsulation, photothermal conversion, electrothermal conversion, battery thermal management, infrared camouflage, two-dimensional materials, thermal conductivity, aerogels, renewable energy

The new composite, designated CNGA, is described in the journal Advanced Composites and Hybrid Materials. Rather than packing conductive carbon into a block, the team assembled the material through heterogeneous ice-templated freeze casting, a process in which growing ice crystals sculpt the internal architecture as the suspension solidifies. The result is a hierarchical porous structure in which double-shell hollow microspheres are spatially segmented and joined by controllable bridges of nitrogen-doped carbon nanosheets. Each microsphere and each bridge plays a distinct electromagnetic role, and because the geometry is imposed during assembly rather than left to chance, the balance between attenuation and impedance matching can be tuned deliberately.

The physics behind the approach is subtle but crucial. When an electromagnetic wave strikes a material, two things must happen for effective absorption. First, the wave has to enter rather than reflect away, which requires the material’s impedance to match that of free space. Second, once inside, the wave’s energy has to be dissipated, typically through dielectric polarization, conduction losses, and magnetic losses. Highly conductive fillers are excellent dissipators but terrible reflectors, bouncing incoming waves off the surface. The distributed RLC framework tackles this by separating the two jobs: the carbon nanosheet bridges provide continuous conductive pathways for energy dissipation, while the spatially distributed hollow microspheres introduce a wealth of heterogeneous interfaces that localize electromagnetic loss without overloading the material with conductivity.

The microspheres themselves are engineered for complexity. Each carries a double shell, and their hollow interiors lower the overall density while multiplying the number of internal boundaries at which electromagnetic waves can be reflected, scattered, and attenuated. Nitrogen doping, in the form of pyridinic and pyrrolic nitrogen sites within the carbon lattice, enhances polarization losses by creating defect-rich sites that trap charge under an oscillating electromagnetic field. Meanwhile, nickel-induced graphitization converts regions of amorphous carbon into more ordered graphitic domains, boosting conduction losses. The two mechanisms act in concert, giving the material multiple channels through which microwave energy can be converted into heat.

The measured performance is striking by any standard. The optimized aerogel achieves a reflection loss of –54.86 decibels, meaning that at the absorption peak, only a vanishingly small fraction of the incoming microwave energy is reflected back toward the source. In practical terms, that is deep into the regime prized for radar absorption, where the power of a returned signal is cut by many orders of magnitude. Equally important, the effective absorption bandwidth—the frequency range over which the material reflects at least 90 percent of incident energy—spans 6.56 gigahertz, covering a broad swath of the microwave spectrum rather than a single narrow band.

What makes these numbers especially notable is the filler loading at which they are achieved: only 8 weight percent. In conventional microwave absorbers, achieving comparable performance often requires loading a matrix with 40 to 70 percent functional filler, which drives up weight and can embrittle the composite. A low loading is essential for aerospace platforms, where every gram matters, and for electronics, where thick or heavy shielding layers are unwelcome. The lightweight aerogel also delivers thermal insulation, with a thermal conductivity of just 0.0605 watts per meter-kelvin, comparable to some of the best commercial insulating foams, and an infrared absorptivity exceeding 95 percent.

The thermal behavior is a direct consequence of the architecture. The hollow interiors and hierarchical porosity mean that heat must navigate a tortuous, largely air-filled path through the material, and air is a notoriously poor thermal conductor. Infrared radiation, meanwhile, is absorbed efficiently across the extended surfaces of the carbon components. This combination means the aerogel can simultaneously suppress heat flow and swallow radiant heat, which matters for applications ranging from protecting sensitive electronics from thermal gradients to managing temperature in aircraft structures where hot and cold zones sit close together.

Mechanical robustness, often the weak point of ultralight aerogels, received its own fix. As-synthesized porous carbon architectures tend to be fragile, but the team found that infiltrating the aerogel with resin raised its compressive strength to 45.70 megapascals without degrading electromagnetic performance. The resin fills the load-bearing framework without disrupting the conductive pathways or the interface density that underpins the wave absorption, turning an admittedly delicate laboratory material into something with realistic prospects for structural use. That step matters because a multifunctional material is only useful if it can survive handling, vibration, and compression in service.

The broader significance of the work lies in its structural philosophy. Instead of optimizing one property at a time and accepting compromises elsewhere, the researchers treated the composite as a spatially regulated system in which geometry, composition, and connectivity are co-designed. The segmentation of the microspheres controls where heterogeneous interfaces appear; the controllable connection of the carbon bridges sets the conductivity of the network; and the ice-templating process allows both to be patterned simultaneously. This structure–property strategy offers a template that other teams can apply to different material chemistries, potentially extending the distributed RLC concept to absorbers that operate in other frequency bands or that combine additional functions such as sensing or mechanical damping.

The work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and two state key laboratories, reflecting the strategic weight placed on electromagnetic compatibility and thermal management in next-generation technology. As wireless devices proliferate and stealth, radar-cross-section management, and high-frequency electronics demand ever better absorbers, materials that swallow microwaves, block heat, and carry mechanical load in a single lightweight layer will only grow more valuable. The CNGA aerogel is a demonstration that, with the right architecture, the classic trade-off between dissipation and impedance matching can be engineered away rather than merely tolerated.

Subject of Research: Hierarchical hollow microsphere-carbon composite aerogels for electromagnetic wave absorption and thermal regulation

Article Title: Spatial segmentation and controllable connection enabled hollow microsphere-carbon distributed RLC networks for multifunctional EM/thermal regulation

Article References: Spatial segmentation and controllable connection enabled hollow microsphere-carbon distributed RLC networks for multifunctional EM/thermal regulation. (n.d.). https://doi.org/10.1007/s42114-026-02073-2

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02073-2

Keywords: electromagnetic wave absorption, microwave absorbers, hollow microspheres, carbon nanosheets, aerogels, thermal insulation, impedance matching, nitrogen doping, ice-templated assembly, RLC networks, lightweight composites, mechanical reinforcement