Liquid Anode Research Articles

Interfacial Engineering with a Nanoparticle-Decorated Porous Carbon Structure on β″-Alumina Solid-State Electrolytes for Molten Sodium Batteries.

We present a novel anode interface modification on the β″-alumina solid-state electrolyte that improves the wetting behavior of molten sodium in battery applications. Heat treating a simple slurry, composed only of water, acetone, carbon black, and lead acetate, formed a porous carbon network decorated with PbOx (0 ≤ x ≤ 2) nanoparticles between 10 and 50 nm. Extensive performance analysis, through impedance spectroscopy and symmetric cycling, shows a stable, low-resistance interface for close to 6000 cycles. Furthermore, an intermediate temperature Na-S cell with a modified β″-alumina solid-state electrolyte could achieve an average stable cycling capacity as high as 509 mA h/g. This modification drastically decreases the amount of Pb content to approximately 3% in the anode interface (6 wt % or 0.4 mol %) and could further eliminate the need for toxic Pb altogether by replacing it with environmentally benign Sn. Overall, in situ reduction of oxide nanoparticles created a high-performance anode interface, further enabling large-scale applications of liquid metal anodes with solid-state electrolytes.

A self-healing liquid metal anode for lithium-ion batteries

The gallium-based liquid metal as one of the self-healing materials has gained wide attention, especially in the energy storage system. However, volume expansion with the “liquid–solid-liquid” transformation process still leads to un-controlled electrode failure, which stimulates the irreversibility of liquid metal and hinders their self-healing effect as the anode for lithium-ion batteries. Herein, the polypyrrole (PPy) with highly conductive and adhesive features is first introduced to fasten the liquid metal nanoparticles (gallium-tin alloy, EGaSn) in the integrated electrode and applied as the anode for lithium-ion batteries. A tightly PPy wrapped EGaSn nanoparticles structure is formed during the in-situ polymerization synthesis process, which effectively avoids the detachment of solid alloyed products. Based on the features of PPy, polyacrylic acid is added to facilitate strengthening the integrity of the electrode by constructing the hydrogen bond. The “dual-insurance” design endows the EGaSn to exhibit superior electrochemical kinetics and an astonishing self-healing effect. As a result, the customized anode displays superior cycling stability (499.8 mAh g−1 after 500 cycles at 1.0 A g−1) and rate capability (350 mAh g−1 at 2.0 A g−1). This work enriches the electrode engineering technology of liquid metal nanoparticles and opens up a new way to customize the self-healing anode for lithium-ion batteries.

Investigation of Electric Discharge With Liquid Electrodes Under Influence on Carbon Fiber

In this work, experimental reseaches of the effect of a DC electric discharge with jet electrolytic cathode and liquid anode at atmospheric pressure on carbon fiber are carried out. Experimental studies were carried out in the voltage range U= 100-1300 V and discharge current 1=0.02-1.8 A. A 20% NaCl solution in process water was used as liquid electrodes. The length of the jet varied lc = 10÷50 mm, the diameter of the jet dc = 1÷3 mm. The optimal form of discharge and modes for processing carbon fiber have been established. The optimal mode of electric discharge which is between a jet electrolytic cathode and a liquid anode at atmospheric pressure is revealed. After processing for 30 s, the tensile strength of the modified samples changed by 7% compared to the untreated sample.

A liquid cathode/anode based solid-state lithium-sulfur battery

Solid-state lithium sulfur batteries constantly suffer from a poor interfacial compatibility between solid-state cathode/anode and electrolyte, and low critical current density of Li metal anode (< 3 mA cm−2). Here, a concept of a liquid cathode/anode based, room-temperature, solid-state lithium sulfur battery with low impedance electrode/electrolyte interfaces is presented. Due to an extremely stable liquid-solid interface with a high compatibility and unique properties of liquid alloy, the liquid Li-amalgam anode based symmetric cells show a superior electrochemical performance, and no internal short circuit occurs as they run at 55.6 mA cm−2 for 10,000 cycles. Liquid Li2S8 polysulfide catholyte can afford a high active material loading (≥135.2 mg mL−1) and has a good contact with the solid-sate electrolyte. The cathode/anode and electrolyte are tightly welded together by the liquid-solid interfaces, and the resulting cells show high performance and good structural stability during cycling.

Coupling of chemical vapor generation with atmospheric pressure glow discharge optical emission spectrometry generated in contact with flowing liquid electrodes for determination of Br in water samples

Miniaturized atmospheric pressure glow discharge (APGD) microplasma devices, operated in contact with a flowing liquid anode (FLA) or a flowing liquid cathode (FLC) and a He jet, were studied for the determination of Br by optical emission spectrometry (OES), after oxidizing the Br- ions to volatile Br2 in the reaction with KMnO4. The concentrations of all reagents needed for the successful operation of the proposed systems were found to be the most crucial parameters and their impact on the intensity of the Br analytical line was studied. Under the optimal conditions, the analytical figures of merit were assessed. The endurance to the matrix effects of both developed methods was also investigated and both of them were found to be strongly insusceptible to the presence of foreign ions. The detection limits (DLs) of Br and was established to be 0.05 and 0.2 mg L-1 for CVG-FLA- and CVG-FLC-APGD, respectively. The developed methods were successfully applied for the determination of relatively low concentrations of Br in selected water samples, spiked with this element, with very good precision (0.9–6.1% as RSD) and trueness (94–110% as recovery). In addition, no significant differences between the results obtained using the external standard calibration and the standard addition method were noted.

Analysis and evaluation of liquid metal anode target material of transmission X-ray tube

In recent years, due to the fluidity and thermal conductivity of the liquid metal, the use of liquid metal as an anode target is one of the ways to improve the brightness of X-ray tubes. In this paper, the optimal thickness and conversion efficiency of three kinds of target materials under different energies were discussed by the Monte Carlo method. The optimal thickness of the gallium target is 6.2 μm when the incident electron beam energy is 50 keV and the optimal thickness of the indium target and the tin target was 4 μm. The X-ray conversion efficiency of the gallium target was 44.28% higher than that of the silver target as well as the ratio of X-ray count with the K lines to total count was 53.38%. The gallium target is suitable to be the material of a liquid metal anode target of transmission X-ray tube within the concerned energy range.

Plasma-solution synthesis of particles containing transition metals

The paper proposes a new method for the synthesis of powders containing transition metals using a plasma-solution system. The reactor was an H-shaped glass cell, the two parts of which were separated by a cellophane membrane. A discharge consisting of two discharges - with a liquid cathode and a liquid anode - a high voltage is applied to titanium electrodes located above the surface of the solution. Aqueous solutions of zinc, iron, cadmium, cobalt, nickel, and copper nitrates were used as the liquid phase. Under the action of the discharge on the liquid anode, in the region of contact of the discharge with the solution the formation of a colloidal suspension was observed. The kinetics of the process of synthesis of solid-phase particles in solution under the action of a discharge have been studied. The chemical composition and morphology of the formed solid phase have been established. The mechanisms of chemical reactions occurring in the solution under the action of plasma, and the mechanisms of formation of transition metal oxides in the process of calcining the synthesized powders have been proposed.

Integration of flow injection-liquid anode glow discharge-fiber spectrometer: A compact analysis system for highly sensitive determination of Hg in water and ore samples

A novel liquid anode glow discharge (LAGD) was structured as a miniaturized excitation source of atomic emission spectrometry (AES), and then integrated with flow injection sampler and fiber spectrometer to form a LAGD-AES system for highly sensitive detection of Hg in water and ore samples. Under the optimal operating parameters, Ag+, Al3+, Ga3+, Mn2+, F− and I− ions seriously interfere with the determination of Hg. Adding 1.5% methanol and 5% formic acid can enhance the net signal intensity of Hg about 2.0- and 2.2-fold and markedly reduce the interferences from Ag+, Al3+, Ga3+, Mn2+, F− and I− ions. The detection limit (LOD) of Hg is reduced from 11.3 μg L−1 for no sensitizer to 8.0 μg L−1 for 1.5% methanol and 4.5 μg L−1 for 5% formic acid. The relative standard deviation (RSD, n = 11) for Hg with no sensitizer, adding 1.5% methanol and 5% formic acid are 3.6%, 2.6% and 3.5%, respectively, and the power consumption is about 10 W. The measurement results of spiked water and ore samples are largely consistent with the spiked value and the verification values measured by ICP-AES. The recoveries of water and ore samples are in the range of 88–116% and 101.6–106.3%, respectively. All results suggested that the LAGD-AES can be employed as a promising technique for highly sensitive determination of Hg because of its compact and portable instrument, low energy consumption, high discharge stability, and no inert gas requirement.

High Current Density and Long Cycle Life Enabled by Sulfide Solid Electrolyte and Dendrite‐Free Liquid Lithium Anode

AbstractLithium metal is the ideal anode candidate but suffers from great challenges including poor thermodynamic stability in liquid organic electrolytes and dendrite nucleation/growth during the continuous plating/stripping process. To solve the difficulties listed above, here, a battery configuration combining a liquid lithium solution anode, a sulfide solid electrolyte, and an interfacial protection layer is proposed to prevent interfacial reaction between the two components. This configuration combines the advantages of liquid‐lithium‐solution anode (dissolve lithium to essentially prevent lithium nucleation) and sulfide solid electrolyte (highest room‐temperature ionic conductivity among all solid electrolytes and ideal mechanical ductility for fully compact layer simply by cold pressing), so that a record‐high current density (17.78 mA cm−2) and long cycle life (nearly 3000 h) are realized. At the same time, the solubility of lithium metal in the liquid Li anode and electrochemical properties of liquid Li anode are systematically studied to find the most suitable liquid Li anode concentration with the highest room‐temperature conductivity (12.2 mS cm−1). This work provides a promising approach and battery configuration for achieving high‐specific‐capacity, high‐energy/power‐density and long‐cycle‐life secondary batteries.

Particle emission with identification from an atmospheric pressure plasma liquid interface

A conspicuous emission phenomenon of luminous particles from the liquid anode surface of an atmospheric pressure DC glow discharge is reported. The emission has been shown to occur when the plasma forms a pattern on the surface of the liquid electrolyte. The spatial-temporal evolutions of the trajectories of emitted particles were studied using a high-speed imaging system. Particles were sampled in flight using a witness plate for analysis. Critical particle characteristics were examined using electron microscope technologies. The morphology of the resulting splats and compositions suggest that they are molten droplets with a great deal of structure, including evidence of nanoprecipitation. A theoretical model was employed to estimate the particle size from the measured splats, which provides a radius range within a hundred micrometers. This experiment leads to the postulation of a mechanism in which particle emission at the plasma liquid interface is likely driven by the Taylor cone effect.

Wearable eutectic gallium-indium liquid fuel cells

With the rapid growth of wearable electronics, the development of wearable fuel cells as a smart power source is receiving ever more attention due to their high energy conversion efficiency, modest operating temperature, and ease of handling. To address the most notable limiting factor, the rigid electrodes, of fuel cells, herein, a eutectic gallium-indium liquid metal with excellent deformability and redox ability has been employed to wearable and rechargeable fuel cells with high performance. Thanks to the optimized Ga/In ratio, which is achieved by balancing the anticorrosion and electrochemical activity of the liquid metal anode, the power density of the fuel cell is as high as 72.8 mW cm−2; to our knowledge, this is the highest power density among existing wearable liquid fuel cells at room temperature. Due to the stable redox properties of liquid metal, the fuel cell was stably cycled for 96 h at 2 mA cm−2 as a rechargeable metal-air battery. Meanwhile, running in feed mode to maintain the proportion of Ga in the anode, the fuel cell and the rechargeable liquid metal fuel cell exhibited stable discharging and cycling performances, respectively, and delivered exemplary performances under various flexibility and stretchability measurements. Based on the fluent and renewable liquid metal anode, this novel high-performance wearable liquid fuel cell shows great promise as a shape-variable energy supply for bionic soft robots and wearable devices.

A Shape‐Variable, Low‐Temperature Liquid Metal–Conductive Polymer Aqueous Secondary Battery

AbstractA shape‐variable aqueous secondary battery operating at low temperature is developed using Ga68In22Sn10 (wt%) as a liquid metal anode and a conductive polymer (polyaniline (PANI)) cathode. In the GaInSn alloy anode, Ga is the active component, while Sn and In increase the acid resistance and decrease the eutectic point to ‐19 °C. This enables the use of strongly acidic aqueous electrolytes (here, pH 0.9), thereby improving the activity and stability of the PANI cathode. Consequently, the battery exhibits excellent electrochemical performance and mechanical stability. The GaInSn–PANI battery operates via a hybrid mechanism of Ga3+ stripping/plating and Cl− insertion/extraction and delivers a high reversible capacity of over 223.9 mAh g−1 and an 80.3% retention rate at 0.2 A g−1 after 500 cycles, as well as outstanding power and energy densities of 4300 mW g−1 and 98.7 mWh g−1, respectively. Because of the liquid anode, the battery without packaging can be deformed with a small force of several millinewtons without any capacity loss. Moreover, at approximately ‐5 °C, the battery delivers a capacity of 67.8 mAh g−1 at 0.2 A g−1 with 100% elasticity. Thus, the battery is promising as a deformable energy device at low temperatures and in demanding environments.

Fundamental Investigations of Factors Affecting Electrical and Transport Properties of Lewis Acidic Chloroaluminate Ionic Liquids for Application in Aluminum Ion Battery

High-performance electrochemical energy storage systems are considered key technologies to sustainable energy economy transition. Despite being one of the most mature and leading-edge battery systems, the future of lithium-ion batteries is shadowed by issues related to resource availability, high production cost, and short lifetime. For these reasons, there has been a great impetus towards the development of alternative battery technologies based on abundant and low-cost materials. Among all, aluminum-ion batteries (AIBs) are particularly promising due to high theoretical capacity, low-cost, and ease of handling and storing of metallic aluminum in ambient conditions.The majority of advanced AIB systems utilizes Lewis acidic chloroaluminate ionic liquid (IL) electrolytes, formed by combining molar excess amount of aluminum chloride (AlCl3) with an organic chloride (RCl; R: organic group). In these systems, the chloroaluminate IL electrolyte behaves as (i) a medium for ion transportation and (ii) an electroactive liquid anode material (also known as anolyte) in AIBs. Among various parameters, the AlCl3/RCl molar ratio (r) and the RCl utilized, are considered the most deterministic factors that affect the performance of AIBs. Several battery and electrolyte performance metrics including achievable specific/volumetric cell-level capacity, electrochemical stability window (ESW), ion transport properties, and conductivity, are known to be dependent on r and the RCl utilized. Despite the importance of chloroaluminate ILs in AIB research field, there is a significant lack of fundamental understandings of the effects of r and RCl on these performance matrices. The elucidation of these effects can provide fundamental insights into approaches for optimizing battery operating conditions as well as revealing important characteristics of high-performance chloroaluminate ILs.This work is focused on investigating the effects of r on the electrical and transport properties of four AlCl3-RCl ILs, where RCl includes EMIMCl (1-ethyl-3-methylimidazolium chloride), BMIMCl (1-buthyl-3-methylimidazolium chloride), TMAHCl (trimethylamine hydrochloride), and TEAHCl (triethylamine hydrochloride). A combined experimental-computational approach is utilized to obtain fundamental insights into the influence of AlCl3/RCl molar ratio on various properties of chloroaluminate ILs including ESW, ion transference number, and ionic conductivity.Our results show that the ESW of Lewis acidic chloroaluminate ILs is strongly dependent on r, as r preliminarily governs the concentration of electroactive anionic species (AlCl4 − and Al2Cl7 −) involved in electrochemical redox reactions. For Lewis acidic chloroaluminate ILs, the reduction of Al2Cl7 − to Al (4Al2Cl7 − + 3e− = Al + 7AlCl4 −) sets the cathodic limit while the oxidation of AlCl4 − to evolve Cl2 (2AlCl4 − = Al2Cl7 − + 1/2Cl2 + e−) defines the anodic limit. The cathodic limiting potential shifts positively while the anodic limiting potential shifts negatively, leading to a narrower ESW width with increasing r. Moreover, electrostatic and van der Waals forces significantly affect the cathodic and anodic limiting potentials as these interactions affect the activity of electroactive species involved. The viscosity of chloroaluminate ILs is particularly useful as it reflects the overall degree of interactions in chloroaluminate ILs. Chloroaluminate IL systems that have higher viscosities exhibit a positive shift of anodic and cathodic limiting potentials. The organic cation R+ is determined to contribute substantially to the total ionic conduction in Lewis acidic chloroaluminate ILs. To fundamentally enhance the electrochemical performance of AIBs employing chloroaluminate ILs, strategies focused on the localization of organic cations should be emphasized as they can effectively improve the proportion of ionic conduction by electroactive chloroaluminate anions while hindering the formation of cation-anion aggregates.

Fabrication and performance of atmospheric plasma sprayed solid oxide fuel cells with liquid antimony anodes

A solid oxide fuel cell (SOFC) with a liquid antimony anode (LAA) is a potential energy conversion technology for the use of impurity-containing fuels. Atmospheric plasma spraying (APS) technology has become a promising LAA-SOFC preparation method because of its economy and convenience. In this paper, button SOFCs with different cathode materials and ratios of pore former were prepared by the APS method and were operated at 750 °C. The effect of the cathode structure on the electrochemical performance of the LAA-SOFCs was analyzed, and an optimized spraying method for LAA-SOFCs was developed. A tubular LAA-SOFC was prepared using the APS method based on the optimized spraying method, and a peak power of 2.5 W was reached. The tubular cell was also measured at a constant current of 2 A for 20 h and was fed with a sulfur-containing fuel to demonstrate its impurity resistance and electrode stability.

Visualization and analysis of coupling between plasmas self-organization and plasma-induced fluid circulation in 1 atm DC glows with liquid anode

In plasma–liquid interactions, the phenomenon of induced liquid flow that originates at the plasma–liquid contact point is important in that it influences mass, charge, and heat transport from the source to the surrounding bulk fluid. Such stimulated flows have been observed in 1 atm glows with a liquid anode. Because the plasma contact point in such discharges is patterned, a natural question is what is the relationship between the observed self-organized patterns and the induced flow field? It is, therefore, of great interest to investigate the coupling mechanism between the self-organization patterns in an atmospheric pressure dc helium glow discharge with a liquid anode and the induced flow circulation. Particle imaging velocimetry is used to probe the flow fields in the plane normal and parallel to the plasma–liquid interface. A strong ascending flow with maximum speed up to 1.5 cm/s and circulation vortices nearby are observed in the plane normal to the interface centered at the plasma attachment. The experiment results suggested that the ascending flow is caused by water evaporation and the vortices are formed by viscous stress. With a self-organization pattern formed, the flow structures become non-static and the circulation vortices are observed to periodically form and decay. In the plane parallel to the interface, a strong swirl flow was found to exist only when the plasma attachment is self-organized. The analysis revealed that the driving mechanism could be the electrohydrodynamics force. Averaged flow velocity over time in the field of view was found to scale linearly with increasing input power and increasing liquid conductivity.

Sandwich-like N-doped carbon nanotube@Nb2C MXene composite for high performance alkali ion batteries

Sodium (Na) and potassium (K) ion batteries are promising for the next-generation energy storage equipment, but compared with lithium (Li) ion battery, their requirements for suitable host materials are much tougher, due to their large ions. 2D accordion-like MXene materials have been studied a lot as electrode materials for Na/K ion battery for their vast interlamellar spacing, but they suffer from layers’ restacking. Herein, a sandwich-like N-doped carbon nanotube@Nb2C (N-CNT@Nb2C) has been synthesized, where N-CNT fibers are sandwiched between MXene layers to fix the whole structure, enhance electrical conductivity, and increase interlamellar spacing. After nitrogen doping, carbon nanotubes own higher conductivity and sites to penetrate N-CNT walls. Consequently, N-CNT@Nb2C shows excellent electrochemical performance in Li, Na, K batteries, such as steady cycling performance for more than 500 cycles. We also test its performance with liquid K–Na alloy as anode of K ion battery. Due to the dendrite-free character of liquid anode, it exhibits better electrochemical performance than with solid K anode. The N-CNT@Nb2C promotes the finding of more suitable electrode materials for alkali ion batteries, deepens understanding of their inner mechanisms, and facilitates their commercialization.

Liquid Alloy Enabled Solid‐State Batteries for Conformal Electrode–Electrolyte Interfaces

AbstractRecent research efforts on solid‐state alkali‐metal batteries are pushing the limit of energy density to a higher level. However, the development of solid‐state batteries is still hindered by many intrinsic limitations, among which the incompatibility between the solid electrolyte and the metal anode is a critical issue attracting massive research attention. A Na–K liquid alloy electrode is designed to form a conformal electrode–electrolyte interface with a solid electrolyte. Much enhanced electrode–electrolyte interfacial contact electrically and physically is observed with liquid metal anodes than solid alkali metals on solid electrolytes. Symmetric cells of the liquid metal electrolytes show much lower overpotential as well as better cyclability than the alkali‐metal electrodes. Excellent cyclability over 500 cycles with reasonable capacity decay and good rate performance of full cells with the sodium rhodizonate and a ferricyanide potassium‐ion cathode are both achieved. By adjusting salt and filler species in the polymer electrolyte, the wettability of liquid metal on the electrolyte can be further improved, and the raised ionic conductivity can further improve the battery performance of such a design.

The application of antioxidant compounds to minimize matrix effects in flowing liquid anode atmospheric pressure glow discharge optical emission spectrometry

To reduce matrix effects originating from concomitant elements (Al, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn) in flowing liquid anode atmospheric pressure glow discharge optical emission spectrometry (FLA APGD OES), the effect of antioxidant addition was investigated. Selected antioxidants, namely ascorbic acid, hydroquinone and its derivatives, i.e., tert-butylhydroquinone, resorcinol, and catechol, were added to the FLA solution and their impact on the analytical response from the analytes (Ag, Cd, Pb, Tl, and Zn) was thoroughly studied. It was established that the presence of the abovementioned foreign elements in a sample solution reduced analyte signals by ∼20–30% for Cd and Tl, ∼40–50% for Ag and Pb, and ∼60% for Zn. The addition of antioxidant compounds allowed to enhance the analyte signals by up to 4.5-fold. The improved analytical response was due to an efficiency increase in analyte transport from the liquid to the plasma phase. Based on these results, the possibilities of matrix effect reductions using antioxidants were summarized. To verify the suitability of the proposed approach, the analyses of simulated manganese steel and mineral water samples (with the use of 0.1% resorcinol) were conducted. Under these conditions, the detection limits (DLs) for Ag, Pb, and Zn were 0.006, 0.3–0.4, and 0.1–0.4 µg L−1, respectively. Measurement precision (expressed as RSD) for the analysis of these samples was approximately 1–2%, and analyte recoveries varied in the range of 99–108%.

DC discharges with a porous liquid anode: Increasing refrigerant efficiency for flash evaporation cooling with charged particle kinetics

The increasing heat flux of a functional device cannot be effectively taken through the simple increment of the liquid spay flux in a vacuum flash vaporization cooling process. Here we demonstrate that a new approach of increasing phase-change efficiency by coupling the charged particle kinetic energy in a DC discharge plasma with a porous liquid water anode can lead to the significant vaporization cooling enhancement effect under similar coolant evaporation rate. Systematic experiments on heat conduction and plasma diagnostics with controlled groups (liquid-free and plasma-free) allow us to describe the correlation patterns of the characteristic properties among a flash evaporation fluid, discharging plasma, and the cooling effects, in detail. It is observed that the temperatures of the working fluid (water) and the metallic heating target have been decreased by 9 and 12 °C, respectively, in plasmas, which is ~80% effective than the controlled cases without plasmas. It is also found that the coolant molecules have been partially ionized, and pumped into a much higher energy state through the discharging collisions, where the rotational temperature of OH(A-X) transition is more than 2000 K based on the diagnostics of the optical emission spectrum. The plasma enhancement effect explored in this work opens novel ways to increase and control the heat flux taken by the vacuum flash vaporization cooling.

Self-healing liquid Ga-based anodes with regulated wetting and working temperatures for advanced Mg ion batteries

Self-healing liquid Ga-based anodes with regulated wetting and working temperatures were fabricated for advanced Mg ion batteries.