Application Of Liquid Metals Research Articles

The Liquid Metal Age: A Transition From Hg to Ga.

This review offers an illuminating journey through the historical evolution and modern-day applications of liquid metals, presenting a comprehensive view of their significance in diverse fields. Tracing the trajectory from mercury applications to contemporary innovations, the paper explores their pivotal role in industry and research. The analysis spans electrical switches, mechanical applications, electrodes, chemical synthesis, energy storage, thermal transport, electronics, and biomedicine. Each section examines the intricacies of liquid metal integration, elucidating their contributions to technological advancements and societal progress. Moreover, the review critically appraises the challenges and prospects inherent in liquid metal applications, addressing issues of recycling, corrosion management, device stability, economic feasibility, translational hurdles, and market dynamics. By delving into these complexities, the paper advances scholarly understanding and offers actionable insights for researchers, engineers, and policymakers. It aims to catalyze innovation, foster interdisciplinary collaboration, and promote liquid metal-enabled solutions for societal needs. Through its comprehensive analysis and forward-looking perspective, this review serves as a guide for navigating the landscape of liquid metal applications, bridging historical legacies with contemporary challenges, and highlighting the transformative potential of liquid metals in shaping future technologies.

Structure effect of wall cooling channel on liquid metal heat transfer in aero-engines

In this study, a model of the cooling channel and an experimental system for heat transfer involving liquid metal are studied, to investigate the influence of the wall cooling channel structure of combustor on the heat transfer process. The error between the experimental and simulated outcomes fall is within 3 %, suggesting that the accuracy of the simulation is satisfactory. The simulation results found that the temperature non-uniformity coefficient can be reduced by 13 % and 7 % through adjusting the aspect ratio under the heat flux of 3 MW/m2 and 1.5 MW/m2 respectively, and the wall temperature of gas side can be reduced by 89 K and 47 K respectively. A smaller aspect ratio is favorable for homogenizing the liquid metal temperature distribution. Longer widths, however, can lead to horizontal thermal stratification, which can be unfavorable for heat transfer. With an aspect ratio and rib thickness of about 0.5 and 0.4 mm, respectively, the cooling channel outlet has the lowest non-uniformity coefficient of temperature and enthalpy, which is conducive to the improvement of the wall energy recovery rate. The optimal cooling channel effectively improves the thermal stratification in channel, and provides theoretical guidance for the suitable application of liquid metal to the combustor wall cooling channel.

Applications of Liquid Metals

Applications of Liquid Metals

Investigation of the spreading of a liquid metal droplet under a vertical magnetic field

In the liquid metal divertor of a magnetic confinement fusion device, the spreading characteristics of the liquid metal are crucial for ensuring the stable operation of the divertor. This study has experimentally investigated the spreading characteristics of a GaInSn alloy droplet on a solid substrate under a strong vertical magnetic field, with the magnetic field intensity ranging from 0 to 2.5 T. First, several parameters of the droplet, such as droplet shape, spreading factor, dynamic contact angle, spreading velocity, and rebound behavior after impacting, were studied without a magnetic field. The fitting relationship between maximum spreading factor βmax and Weber number We was obtained and has been compared with the scaling laws from the literature. Furthermore, the effect of the vertical magnetic field on those parameters has been investigated systematically. Quantitative results on βmax and the maximum spreading time tDmax, varied with the Hartmann number (Ha) and the We number, provide a comprehensive understanding of the spreading dynamics. The specific relationship between βmax and We number under different magnetic field intensities (B) shows that a vertical magnetic field has a great inhibiting effect on liquid metal droplet spreading. Finally, the influence of oxidation on droplet spreading characteristics also has been studied. These basic findings are important for the application of liquid metal on a divertor/limiter in a fusion reactor, offering a theoretical reference engineering design.

Fabrication Aspects and Performance Characterization of α-Al2O3/AlPO4 Based Sandwich Configuration Flow Channel Inserts and Coatings for High Temperature Liquid Metal Applications

Abstract Liquid metals (LMs) exhibit several key characteristics justifying their utilization as coolants and breeders for nuclear fusion reactors and advanced fission reactors. In fusion reactors, the LMs confront an exorbitantly high flow retarding force, due to the magneto-hydro-dynamics (MHD) effect, imposing significant demands on the pumping power and designs of ancillary coolant systems. Corrosion of structural materials leading to activated corrosion products and coolant chemistry control are some of the vital issues common to both fusion and fission reactors employing liquid lead (Pb) and its alloys. To address these concerns, different technological solutions such as flow channel inserts (FCIs) and high temperature compatible corrosion resistant coatings are being investigated to provide a chemical and/or electrical isolation between the LM and structural material for advanced reactors. In this study, three different prototype geometries (circular, square, and 90 deg bend) of steel-insulator-steel sandwich FCIs are fabricated for fusion reactor applications and an extensive characterization of the electrical insulation is performed over an operating temperature range of 100 °C–600 °C. Welding trials and pneumatic pressure tests up to 10 kg/cm2 (g) are performed on the assemblies to validate the electrical and mechanical integrity over typical fusion reactor operational regime. This paper presents detailed fabrication aspects along with quantitative estimations of insulation filling density, electrical insulation performance and, for the first time, a detailed systematic study of insulation degradation resulting from the combined effects of tungsten inert gas (TIG) welding, exposure to pressure and machining operations on these FCIs. The paper also provides critical details derived from the metallurgical examinations and visual observations from the destructive tests executed on the prototypes. Further, from an implementation perspective toward Lead-cooled Fast Reactors (LFRs), a preliminary feasibility assessment of the α-Al2O3/AlPO4 coating is performed through thin film deposition trials on planar and non-planar substrates followed by mechanical characterizations, such as coating thickness, surface roughness, adhesion strength and microhardness. Metallurgical analyses are presented and discussed to assess Pb ingress after 700 h of continuous exposure to molten Pb alloy at 300 °C–400 °C.

Light-Induced Dynamic Manipulation of Liquid Metal Droplets in the Ambient Atmosphere.

Dynamic manipulation of liquid metal (LM) droplets, a material combining metallicity and fluidity, has recently revealed tremendous potential in developing unconstrained microrobots. LM manipulating techniques based on magnetic fields, electric fields, chemical reactions, and ion concentration gradients in liquid environments have advanced considerably, but dynamic manipulation in air remains a challenge. Herein, a photoresponsive pyroelectric superhydrophobic (PPS) platform is proposed for noncontact, flexible, and controllable manipulation in the ambient atmosphere. The PPS can generate additional free charges when illuminated by light, thus generating the driving force to manipulate liquid metal droplets. By using the synergistic effect of dielectrophoretic and electrostatic forces generated under light navigation, liquid metal droplets can achieve a series of complex motion behaviors, such as climbing slopes, going over steps, avoiding obstacles, crossing mazes, etc. We further extend the light control of liquid metal droplets to robots applied in electronic circuits, including circuit switching robots and circuit welding robots. This light strategy for manipulating liquid metal droplets provides insights into the development of intelligent, responsive interfaces and simultaneously provides possibilities for the application of liquid metals.

Printing of liquid metal by electrically modulating of interface tension in liquid environment

In recent years, gallium-based liquid metal has emerged as a prominent research material in the realm of flexible electronics, owing to its exceptional electrical conductivity and deformability. The crux of developing flexible electronic devices using liquid metal as a conductive material lies in the patterning of the liquid metal. Inkjet printing technology possesses the capability to efficiently craft functional patterns by printing any inkable material. However, due to the facile oxidation of the gallium-based liquid metal surface in ambient air, leading to the formation of oxide films and the presence of high surface tension, conventional inkjet printing techniques are incapable of directly rendering liquid metal prints. This manuscript introduces a refined and remarkably efficient approach to inkjet printing utilizing the liquid metal. By deftly adjusting the interfacial tension of the liquid metal at the nozzle with ultra-low potentials, falling within the 2-V range, the achievement of on-demand, micron-scale liquid metal microdroplet ejection printing surpassing 3 kHz is brought to fruition. This article delves into unraveling the mechanisms of potential modulation on the interfacial tension of the liquid metal at the nozzle, as well as the fundamental theories pertaining to the formation and migration of liquid metal microdroplets. These insights establish a theoretical and technical foundation for the application of liquid metals in the field of electronic printing.

Gallium-Based Liquid Metals in Rechargeable Batteries: From Properties to Applications.

Gallium-based (Ga-based) liquid metals have attracted considerable interest due to their low melting points, enabling them to feature both liquid properties and metallic properties at room temperature. In light of this, Ga-based liquid metals also possess excellent deformability, high electrical and thermal conductivity, superior metal affinity, and unique self-limited surface oxide, making them popular functional materials in energy storage. This provides a possibility to construct high-performance rechargeable batteries that are deformable, free of dendrite growth, and so on. This review primarily starts with the property of Ga-based liquid metal, and then focuses on the potential applications in rechargeable batteries by exploiting these advantages, aiming to construct the correlation between properties and structures. The glorious applications contain interface protection, self-healing electrode construction, thermal management, and flexible batteries. Finally, the opportunities and obstacles for the applications of liquid metal in batteries are presented.

A liquid metal based, integrated parallel electroosmotic micropump cluster drive system.

The application of liquid metal in a microfluidic system enables the fabrication of highly integrated on-chip electroosmotic micropumps (EOPs). In this work, a low-voltage driveable integrated parallel EOP cluster drive system is proposed. This system consists of two layers, a branch-channel layer and a trunk-channel layer. The lower branch-channel layer contains separate parallel pumping channels and a pair of comb liquid metal electrodes. The separated branch channels are connected together through the trunk channels in the upper layer. With this structural arrangement, the parallel micropumps form an integrated micropump cluster for larger pumping capacity. The distance between the pumping channel and the electrode next to it is controlled to 20 μm. To guide the pump design, parametric studies are performed and fully discussed. According to the experimental results, the micropump cluster can be driven at a low voltage of 0.5 V, and the flow rate reaches 274 nL min-1 at 5 V. In addition, the paper finally proposes an electrode protection strategy and an integrated pump-valve drive system which is expected to solve the shortcoming of electroosmotic pumps in terms of long-time storage and driving.

Technology Development for the Pyrolysis of Hydrocarbons in Liquid Metal

AbstractThis article describes the development of a new technology based on the application of liquid metal and aims to produce hydrogen by decarbonization (pyrolysis process) of both natural and artificially synthesized hydrocarbons. When biogas with a sufficiently high carbon dioxide content is used as a feedstock, or by the targeted addition of CO2 to methane, a mixture of hydrogen and carbon monoxide (synthesis gas) can be produced. Furthermore, the paper describes another very interesting application of the technology to create negative emissions. In this scenario, the processes direct air capture, methanation, electrolysis and methane pyrolysis are combined to synthesize solid carbon from atmospheric CO2. The broad range of process options investigated indicates that, when the technology is scaled up to industrial scale, the result will be a process that is flexible in both the use of reactants and the resulting products.

Micro-encapsulation of a low-melting-point alloy phase change material and its application in electronic thermal management

The application of liquid metal (LM) with high thermal conductivity in electronic thermal management is an emerging hotspot, but leakage of LM can cause environmental pollution and lead to corrosion of electronic equipment, thereby affecting the safety of its operation. Moreover, large temperature fluctuation will be caused for the limited thermal storage capacity of LM. To solve the above problems, it is urgent to develop LM-based microcapsules with high thermal conductivity and high thermal storage capacity. Herein, a novel micro-encapsulated phase change material (MEPCM) with an internal void, composed of liquid metal Sn–Bi–In core and PMMA shell, was firstly fabricated via liquid phase micro-encapsulation method. The results showed that microcapsules maintained good morphology and efficient thermal storage capacity (246.46 J cm−3) after 300 thermal cycles, 97.12% of that before the cycle (253.77 J cm−3). Subsequently, the MEPCM-based composite was prepared by mixing MEPCM into thermal gel. The enthalpy of 50 wt% MEPCM composite was 126.72 J cm−3, and the thermal conductivity of it was 3.23 W m−1·K−1, while that of thermal gel was 0.98 W m−1·K−1. Then the 50 wt% MEPCM-based composite was applied for LED chip, and the temperature of chip was 71.1 °C, 11.2 °C lower than that of thermal gel. Therefore, MEPCM-based composites with high thermal conductivity and thermal storage capacity are considerably potential for electronic thermal management.

Universal Renaissance Strategy of Metal Fluoride in Secondary Ion Batteries Enabled by Liquid Metal Gallium.

All-solid-state alkali ion batteries represent a future trend in battery technology, as well as provide an opportunity for low-cost metal fluoride electrode materials, if certain intrinsic problems can be resolved. In this work, a liquid metal activation strategy is proposed in which liquid Ga elements are generated in situ and doped into the LiF crystal structure by introducing a small amount of GaF3 . Benefiting from these two Ga states of existence, in which the liquid metal Ga can continuously maintain conformable ion/electron-transport networks, while doped Ga in the LiF crystal structure catalyzes LiF splitting, the lithium-ion storage capacity of MnF2 significantly increasesby 87%. A similar effect can be obtained in FeF3 , where the sodium-ion storage capacity is enhanced by 33%. This universal strategy with few restrictions can be used to realize a complete renaissance of metal fluorides, as well as offer an opportunity for the new application of liquid metals in the field of energy storage.

On the application of liquid metal cooling for electronic switching devices

Increasingly smaller and lighter power electronics converters are needed for the advancement of electrified transport. The development of high heat flux heat sinks is imperative to maintain modern converters at an operable temperature. So far, liquid metal based heat sinks have not received as much attention as other solutions, yet they provide a multitude of benefits beyond their superior thermal conductivity. Their use with compact magnetohydrodynamic pumping systems, straight-forward incorporations of active cooling techniques, elimination of water corrosion issues in power converter systems using press-pack IGBT’s and a significant increase in thermal performance in conventional pin–fin structures are demonstrated in this paper. Some additional functionalities of liquid metal systems which could be explored in the future are also highlighted.

A novel application of liquid metal: Stretchable encapsulating material

A novel application of liquid metal: Stretchable encapsulating material

Recent progress in liquid metal printing and its applications.

This paper focuses on the latest research printing technology and broad application for flexible liquid metal (LM) materials. Through the newest template printing method, centrifugal force assisted method, pen lithography technology, and laser method, the precision of liquid metal printing on the devices was improved to 10 nm. The development of novel liquid metal inks, such as PVA-LM ink and ethanol/PDMS/LM double emulsion ink, have further enhanced the recovery, rapid printing, high conductivity, and strain resistance. At the same time, liquid metals also show promise in the application of biochemical sensors, photocatalysts, composite materials, driving machines, and electrode materials. Liquid metals have been applied to biomedical, pressure/gas, and electrochemical sensors. The sensitivity, biostability, and electrochemical performance of these LM sensors were improved rapidly. They could continue to be used in healthy respiratory, heartbeat monitoring, and dopamine detection. Meanwhile, the applications of liquid metal droplets in catalytic-assisted MoS2 deposition, catalytic growth of two-dimensional (2D) lamellar, catalytic free radical polymerization, catalytic hydrogen absorption/dehydrogenation, photo/electrocatalysis, and other fields were also summarized. Through improving liquid metal composites, magnetic, thermal, electrical, and tensile enhancement alloys, and shape memory alloys with excellent properties could also be prepared. Finally, the applications of liquid metal in micro-motors, intelligent robot feet, nanorobots, self-actuation, and electrode materials were also summarized. This paper comprehensively summarizes the practical application of liquid metals in different fields, which helps understand LMs development trends, and lays a foundation for subsequent research.

Dynamic Leakage‐Free Liquid Metals

AbstractLeakage is a significant issue that prevents the widespread application of liquid metals (LMs) and an effective solution has not yet been developed. One potential solution is to use the high surface tension of LMs to encapsulate them in a porous material. However, it is challenging as it is difficult to infuse LMs into tiny pores. This study proposes a bottom‐up strategy where LMs are doped with NdFeB@Ag particles, which are then magnetized to form a tight porous structure. This structure is robust and resistant to collapse under mechanical deformation. Therefore, LMs can be reliably immobilized within the pores between the particles, and a dynamic leakage‐free state is achieved. The encapsulated LMs demonstrate excellent properties including a large latent heat of 153.46 J cm−3, high thermal conductivity of 35.62 W m−1 K−1, and enhanced electrical conductivity of 69.61%, which efficiently extends their functional scope and potential value.

New Strategy and Excellent Fluorescence Property of Unique Core–Shell Structure Based on Liquid Metals/Metal Halides

The further applications of liquid metals (LMs) are limited by their common shortcoming of silver-white physical appearance, which deviates from the impose stringent requirements for color and aesthetics. Herein, a concept is proposed for constructing fluorescent core-shell structures based on the components and properties of LMs, and metal halides. The metal halides endow LMs with polychromatic and stable fluorescence characteristics. As a proof-of-concept, LMs-Al obtained by mixing of LMs with aluminum (Al) is reported. The surface of LMs-Al is transformed directly from Al to a multi-phase metal halide of K3 AlCl6 with double perovskites structure, via redox reactions with KCl + HCl solution in a natural environment. The formation of core-shell structure from the K3 AlCl6 and LMs is achieved, and the shell with different phases can emit a cyan light by the superimposition of the polychromatic spectrum. Furthermore, the LMs can be directly converted into a fluorescent shell without affecting their original features. In particular, the luminescence properties of shells can be regulated by the components in LMs. This study provides a new direction for research in spontaneous interfacial modification and fluorescent functionalization of LMs and promises potential applications, such as lighting and displays, anti-counterfeiting measures, sensing, and chameleon robots.

Magnetic liquid metal scaffold with dynamically tunable stiffness for bone tissue engineering.

The stiffness of most biomaterials used in bone tissue engineering is static at present, and does not provide an ideal biomimetic dynamical mechanical microenvironment for bone regeneration. To simulate the dynamic stiffness better during bone repair, the preparation of dynamic materials, especially hydrogels, has aroused researchers' interest. However, there are still many problems limiting the development of hydrogels such as small-scale stiffness changes and unstable mechanical properties. Here, magnetic liquid metal (MLM) was introduced into bone tissue engineering for the first time. A MLM scaffold was obtained by adding magnetic silicon dioxide particles (Fe@SiO2) into galinstan. Furthermore, a porous MLM (PMLM) scaffold was obtained by adding polyethylene glycol as a template to the MLM scaffold. Both scaffolds can respond to external magnetic fields, so changing the magnetic field intensity can achieve a large-scale of dynamic stiffness change. The results showed that the MLM scaffold has good biocompatibility and can promote the osteogenic differentiation of mesenchymal stem cells (MSCs). The PMLM scaffold with dynamic stiffness can promote new bone regeneration and osseointegration in vivo. Our research will open up a new field for the application of liquid metal and bring new ideas for the development of bone tissue engineering materials.

Inhomogeneous dealloying kinetics along grain boundaries during liquid metal dealloying

In this study, the inhomogeneous dealloying phenomenon during the liquid metal dealloying (LMD) was investigated using Fe50Ni50+Mg and (FeCo)50Ni50+Mg systems. For the Fe50Ni50+Mg system, the inhomogeneous dealloying and wetting of Mg melt occurred along triple junction (TJ) and grain boundary (GB). Temperature increase enhances the inhomogeneous dealloying kinetics and leads to the formation of the plate-shaped abnormal ligaments at the GB region. The energy banlance between a GB energy (γGB) and solid-liquid interface energies (γsl) is the key factor governing the inhomogeneous dealloying and wetting. Particularly, the low-energy twin boundaries were unaffected by the inhomogeneous dealloying. Therefore, precursor microstructure is an important factor determining the final morphology of dealloyed material as well as its physical properties. In the case of the (FeCo)50Ni50 precursor, all TJ and GB were stable against the preferred penetration of Mg melt from 600 °C to 800 °C. It was concluded that a minor addition of alloying elements (V or Cr) changes GB characteristics as well as γsl of the precursor alloy. Consequently, this significantly influences dealloying mechanisms and final morphology of the dealloyed material. The current findings demonstrate the importance of GB engineering in the precursor materials for the technological application of liquid metal dealloying for the synthesis of advanced structural and functional materials.

A Highly Stretchable and Permeable Liquid Metal Micromesh Conductor by Physical Deposition for Epidermal Electronics.

Stretchable electronics allow functional devices to integrate with human skin seamlessly in an emerging wearable platform termed epidermal electronics. Compliant conductors represent key building components for functional devices. Among the various candidates, gallium-based liquid metals stand out with metallic conductivity and inherent deformability. Currently, the widespread applications of liquid metals in epidermal electronics are hindered by the low steam permeability and hence unpleasant wearing perceptions. In this study, a facile physical deposition approach is established to create a liquid metal micromesh over an elastomer sponge, which exhibits low sheet resistance (∼0.5 Ω sq-1), high stretchability (400% strain), and excellent durability. The porous micromesh shows textile-level permeability to achieve long-term wearing comfort. The conformal interaction of the liquid metal micromesh with the skin gives rise to a low contact impedance. An integrated epidermal sensing sleeve is demonstrated as a human-machine interface to distinguish different hand gestures by recording muscle contractions. The reported stretchable and permeable liquid metal conductor shows promising potentials in next-generation epidermal electronics.