Low-temperature Metal Research Articles

Electrolyte Design via Cation-Anion Association Regulation for High-Rate and Dendrite-Free Zinc Metal Batteries at Low Temperature.

Low-temperature zinc metal batteries (ZMBs) are highly challenged by Zn dendrite growth, especially at high current density. Here, starting from the intermolecular insights, we report a cation-anion association modulation strategy by matching different dielectric constant solvents and unveil the relationship between cation-anion association strength and Zn plating/stripping performance at low temperatures. The combination of comprehensive characterizations and theoretical calculations indicates that moderate ion association electrolytes with high ionic conductivity (12.09 mS cm-1 at -40 °C) and a stable anion-derived solid electrolyte interphase (SEI) jointly account for highly reversible and dendrite-free Zn plating/stripping behavior, resulting in high-rate and ultrastable cycle performance at low temperature. As a result, at -40 °C, Zn//Zn cells can stably cycle over 400 h at 5 mA cm-2 and 10 mAh cm-2 and Zn//Cu cells exhibit an exceptional average Coulombic efficiency (CE) of 99.91% for 1800 cycles at 1 mA cm-2 and 1 mAh cm-2. Benefiting from enhanced low-temperature Zn plating/stripping performance, Zn//PANI full cells stably operate for 12,000 cycles at 0.5A g-1 and 35,000 cycles at 5 A g-1. Impressively, at -60 °C, Zn//Cu cells still display a high average CE of 99.68% for 2000 cycles. This work underscores the crucial effect of cation-anion association regulation for high-rate and dendrite-free Zn metal anodes, deepening the understanding of intermolecular interaction insights for low-temperature electrolyte design.

Intermetallic Compounds for Hydrogen Storage: Current Status and Future Perspectives.

Intermetallic compounds are an emerging class of materials with intriguing hydrogen activation and storage capabilities garnering attention for their application in low-temperature hydrogen storage and metal hydride batteries. However, none of the existing intermetallic compounds have met the gravimetric hydrogen storage capacity target of 5.5wt.%. Some A2B-type intermetallic compounds, like Mg2Ni, Mg2Co, and Mg2Fe, approach this target but require high temperatures for hydrogen desorption limiting their use in low-temperature hydrogen storage and automotive applications. Conversely, some intermetallic compounds like ZrV2 and LaNi5, exhibit hydrogen desorption at ambient conditions but with comparatively lower hydrogen storage capacities. This review article provides a comprehensive account of the different types of intermetallic compounds, their synthesis using different solidification-based and solid-state diffusion-based approaches, and their metallurgical and structural properties. It examines the complex interdependencies between the structural parameters of intermetallic compounds and hydrogen storage performance. A definitive but non-linear correlation is identified between void volume and gravimetric hydrogen storage capacities while lattice structure, evolution of lattice structure with hydrogen absorption, enthalpy of hydride formation, and hydrogen activation reactivities of intermetallic compounds are identified as critical parameters governing hydrogen storage performance.

Fluorinated co-solvent electrolytes enable lithium metal batteries to operate at low temperatures

Enhancing the energy output of batteries in low temperatures is critical to broadening the application areas of advanced electronic devices, which can be accomplished by utilizing high-voltage cathodes to match lithium metal anode, optimizing electrolyte electrochemical windows and forming stable solid electrolyte interphases to provide facile ion-transmission kinetics at low temperature. Herein, we demonstrate a fluorinated ester co-solvent electrolyte, which applies 1 M LiPF6 in an ethyl 4,4,4-trifluoro butyrate/fluoroethylene carbonate (FEC) (4/1 by volume ratio) that jointly satisfies high voltage cathode and lithium metal anode reversibility at required ambient. The performance of the battery is due to the rapid dissociation of Li+ and the formation of a fluorine-rich inorganic electrolyte interface in the fluorinated solvent. Therefore, the fluorinated ester co-solvent electrolyte system can provide 209.9 mAh g−1, 194.8 mAh g−1, and 175.5 mAh g−1 when discharged at room temperature, −20 ℃ and −40 ℃, respectively, those far exceeds the performance of carbonate electrolytes. This work advances the development of low-temperature lithium metal batteries.

Exploring low temperature-sputtered indium tin oxide (ITO) as an anti-reflection layer for silicon solar cells

Abstract This paper tackles challenges in silicon (Si) solar cells, specifically the use of hazardous Phosphorus Oxychloride (POCl3) for emitter formation and silane/ammonia for the Anti-Reflective Coating (ARC) layer, accompanied by high-temperature metallization. The study proposes an eco-friendly ARC layer process, replacing toxic materials. Indium Tin Oxide (ITO) with a refractive index of ∼2.0 is suggested as a non-toxic substitute for SiN x in the ARC layer. ITO enables fine-tuning of optical parameters and, with its electrical properties, supports low-resistivity contacts through efficient, low-temperature metallization processes. ITO-passivated solar cells with Ag polymer paste as a front contact exhibit promising characteristics: a commendable photocurrent density (J sc) of 20 mA cm−2 at 850 °C, low series resistance (R s) of 1.9 Ω, and high shunt resistance (R shunt) of 28.9 Ω, as demonstrated by illuminated I–V measurements. Implementing ITO as the ARC on a less toxic emitter junction enhances Si solar cells’ current density gain, minimizing current leakage during high-temperature processing. In conclusion, adopting less toxic materials and employing low-temperature processing in passive silicon solar cell fabrication presents an attractive alternative for cost reduction and contributes to environmentally sustainable practices in green manufacturing.

An Atomic-scale Explanation For The High Selectivity Towards Carbon Dioxide Reduction Observed On Liquid Metal Catalysts.

The low-temperature liquid metals Ga-In and Ga-Snhave previously showcased >95% selectivity towards the electrochemical reduction of CO2to formate, occuring only when the alloys are melted, not solid.Here, density functional theory molecular dynamics and metadynamics simulations reveal that CO2does not directly adsorb to the Ga-alloy surface, but instead is reduced indirectly by reaction with an adsorbed hydrogen. The reaction barrier is vastly more favourable when this process occurs at In or Sn sites (average: 0.26 eV), than when it occurs on Ga (average: 0.47 eV). However, there is no difference in barrier between solid and liquid surfaces. Instead, we find that Hadsis mobile only on the liquid surface, travelling due to the motion of the liquid beneath. This process drives Hadsto In/Sn sites, allowing low-barrier CO2reduction to occur only on the liquid. Therefore, the dynamic motion of liquid metal catalysts can underpin their unique reactivity. The result has far reaching implications for any protonation reaction conducted with a liquid metal catalyst.

Simultaneously Boosting Catalyst Activity and Stability by Construction of Low-Temperature Strong Metal−Support Interaction

Simultaneously Boosting Catalyst Activity and Stability by Construction of Low-Temperature Strong Metal−Support Interaction

Hypoeutectic Liquid Metal Printing of 2D Indium Gallium Oxide Transistors.

2D native surface oxides formed on low melting temperature metals such as indium and gallium offer unique opportunities for fabricating high-performance flexible electronics and optoelectronics based on a new class of liquid metal printing (LMP). An inherent property of these Cabrera-Mott 2D oxides is their suboxide nature (e.g., In2O3-x), which leads high mobility LMP semiconductors to exhibit high electron concentrations (ne >1019cm-3) limiting electrostatic control. Binary alloying of the molten precursor can produce doped, ternary metal oxides such as In-X-O with enhanced electronic performance and greater bias-stress stability, though this approach demands a deeper understanding of the native oxides of alloys. This work presents an approach for hypoeutectic rapid LMP of crystalline InGaOx (IGO) at ultralow process temperatures (180°C) beyond the state of the art to fabricate transistors with 10X steeper subthreshold slope and high mobility (≈18cm2Vs-1). Detailed characterization of IGO crystallinity, composition, and morphology, as well as measurements of its electronic density of states (DOS), show the impact of Ga-doping and reveal the limits of doping induced amorphization from hypoeutectic precursors. The ultralow process temperatures and compatibility with high-k Al2O3 dielectrics shown here indicate potential for 2D IGO to drive low-power flexible transparent electronics.

Catalyst–sulfur bidirectional stimulation to accelerate redox kinetics for high-performance cryogenic lithium-sulfur batteries

The development of cryogenic lithium-sulfur batteries (LSBs) suffers from the sluggish reaction kinetics and the shuttle effect of polysulfide. In order to accelerate the redox process and improve the utilization rate of elemental sulfur at the low temperature, we first propose catalyst–sulfur bidirectional stimulation to accelerate redox kinetics for high-performance cryogenic LSBs. Theoretical calculation and experimental results suggest that the selenium-doped MoS2 (SeDMoS2) catalyst can not only effectively capture and anchor polysulfide but also can interact with the sulfur species to stimulate each other, thus boosting the low-temperature kinetics and optimizing the cryogenic capacity. Quite impressively, with the assistance of the bidirectional stimulation between the SeDMoS2 catalyst and sulfur, the LSB can deliver a high initial capacity of 732 mAh g−1, and only ∼0.3% of the capacity is attenuated per cycle during 100 cycles at the low temperature of −40 °C. This strategy throws light on the further development of high-capacity cryogenic LSBs and points the way to explore other low-temperature metal batteries.

Low-Temperature Area-Selective Metal Passivation Bonding Platform for Heterogeneous Integration

Low-Temperature Area-Selective Metal Passivation Bonding Platform for Heterogeneous Integration

Forming a disordered atomic layer to bond TiN or AlN ceramic with Sn[sbnd]9Zn metal under ultrasonication

A disordered atomic layer instead of traditional intermetallic compounds is formed in the bonding interface of ceramic and metal in the metallization of ceramics under ultrasonication. A deep understanding of the bonding mechanism between poor-wetted ceramics and low-temperature metals remains limited with regard to high metallization efficiency and nanoscale bonding structure. In this work, the metallization of AlN and TiN ceramics was realized using Sn9Zn metal with the aid of ultrasonication. The microstructure, energy, and element sources of the ceramic/metal interface were analyzed. Results show that a nanoscale amorphous layer is formed between the ceramics and the metal, and this layer can bond easily with AlN or TiN and Sn9Zn because of the irregular arrangement of its atoms. Some dispersed nanocrystals are also present in the amorphous bonding layer. The thermal effect of ultrasonic cavitation produces a high temperature above 106 K, which provides the energy for the bonding of AlN or TiN with Sn9Zn. O and Zn accumulate in the Sn-9Zn/AlN bonding layer. Zn originates from Sn9Zn. O could be from the O2 dissolved in the liquid solder or the O2 adhering to the ceramic. A small amount of AlN decomposes because of its high ΔG of decomposition. However, TiN decomposes into Ti and N2 under the extreme condition caused by ultrasonic cavitation. The accumulated Ti in the Sn-9Zn/TiN bonding layer originates from TiN. The source of the accumulated O is the same as that of Sn-9Zn/AlN bonding layer.

Low-Temperature and Fast-Charging Lithium Metal Batteries Enabled by Solvent–Solvent Interaction Mediated Electrolyte

Low-Temperature and Fast-Charging Lithium Metal Batteries Enabled by Solvent–Solvent Interaction Mediated Electrolyte

Fast Interfacial Defluorination Kinetics Enables Stable Cycling of Low-Temperature Lithium Metal Batteries.

The development of low-temperature lithium metal batteries (LMBs) encounters significant challenges because of severe dendritic lithium growth during the charging/discharging processes. To date, the precise origin of lithium dendrite formation still remains elusive due to the intricate interplay between the highly reactive lithium metal anode and organic electrolytes. Herein, we unveil the critical role of interfacial defluorination kinetics of localized high-concentration electrolytes (LHCEs) in regulating lithium dendrite formation, thereby determining the performance of low-temperature LMBs. We investigate the impact of solvation structures of LHCEs on low-temperature LMBs by employing tetrahydrofuran (THF) and 2-methyltetrahydrofuran (2-MeTHF) as comparative solvents. The combination of comprehensive characterizations and theoretical simulations reveals that the THF-based LHCE featured with a strong solvation strength exhibits fast interfacial defluorination reaction kinetics, thus leading to the formation of an amorphous and inorganic-rich solid-electrolyte interphase (SEI) that can effectively suppress the growth of lithium dendrites. As a result, the highly reversible Li metal anode achieves an exceptional Coulombic efficiency (CE) of up to ∼99.63% at a low temperature of -30 °C, thereby enabling stable cycling of low-temperature LMB full cells. These findings underscore the crucial role of electrolyte interfacial reaction kinetics in shaping SEI formation and provide valuable insights into the fundamental understanding of electrolyte chemistry in LMBs.

Metal cation crosslinked, partially reduced graphene oxide membranes with enhanced stability for high salinity, produced water treatment by pervaporative separation

Graphene oxide (GO)-based membranes hold significant promise for applications ranging from energy storage to protective coatings, to saline water and produced water treatment, owing to their chemical stability and unique barrier properties achieving a high selectivity for water permeation. However, unmodified GO membranes are not stable when submerged in liquid water, creating challenges with their commercial utilization in aqueous filtration and pervaporation applications. To mitigate this, we develop an approach to modify GO membranes through a combination of low temperature thermal reduction and metal cation crosslinking. We demonstrate that Zn2+–rGO and Fe3+–rGO membranes had the highest permeation flux of 8.3 ± 1.5 l m−2 h−1 and 7.0 ± 0.4 l m−2 h−1, for saline water separation, respectively, when thermally reduced after metal cross-linking; These membranes maintained a high flux of 7.5 ± 0.7 l m−2 h−1, and 5.5 ± 0.3 l m−2 h−1 for produced water separation, respectively. All the membranes had a salt rejection higher than 99%. Fe3+ crosslinked membranes presented the highest organic solute rejections for produced water of 69%. Moreover, long term pervaporation testing was done for the Zn2+–rGO membrane for 12 h, and only a minor drop of 6% in permeation flux was observed, while Zn2+–GO had a drop of 24%. Both modifiers significantly enhanced the stability with Fe3+–rGO membranes displaying the highest mechanical abrasion resistance of 95% compared to non-reduced and non-crosslinked GO. Improved stability for all samples also led to higher selectivity to water over organic contaminants and only slightly reduced water flux across the membrane.

Superfast Zincophilic Ion Conductor Enables Rapid Interfacial Desolvation Kinetics for Low-Temperature Zinc Metal Batteries.

Low-temperature rechargeable aqueous zinc metal batteries (AZMBs) as highly promising candidates for energy storage are largely hindered by huge desolvation energy barriers and depressive Zn2+ migration kinetics. In this work, a superfast zincophilic ion conductor of layered zinc silicate nanosheet (LZS) is constructed on a metallic Zn surface, as an artificial layer and ion diffusion accelerator. The experimental and simulation results reveal the zincophilic ability and layer structure of LZS not only promote the desolvation kinetics of [Zn(H2O)6]2+ but also accelerate the Zn2+ transport kinetics across the anode/electrolyte interface, guiding uniform Zn deposition. Benefiting from these features, the LZS-modified Zn anodes showcase long-time stability (over 3300h) and high Coulombic efficiency with ≈99.8% at 2mA cm-2, respectively. Even reducing the environment temperature down to 0°C, ultralong cycling stability up to 3600h and a distinguished rate performance are realized. Consequently, the assembled Zn@LZS//V2O5-x full cells deliver superior cyclic stability (344.5 mAh g-1 after 200 cycles at 1 A g-1) and rate capability (285.3 mAh g-1 at 10 A g-1) together with a low self-discharge rate, highlighting the bright future of low-temperature AZMBs.

Low temperature metal induced crystallization of orientation-preferred polycrystalline germanium with n- and p-type doping for device applications

A metal-induced crystallization (MIC) doping method is proposed for the fabrication of n- and p-type doping polycrystalline germanium (poly-Ge). This method involves the use of amorphous- (α-) Ge/metal/α-Ge/crystal-Ge stacked structure to achieve orientation-preferred poly-Ge on Ge (100) substrate at a very low temperature of 240℃. Aluminum (Al) and bismuth (Bi) metal layers are selected for p- and n- type doping sources, respectively. The thickness ratio of metal to α-Ge is optimized to obtain dense poly-Ge. Raman spectrum, scanning electron microscopy and electron backscattered diffraction characterizations confirm that the crystallized α-Ge exhibits a preferred orientation along (100) with a smooth surface. The p- and n- type doping concentrations are evaluated to be 2.2×1021 cm−3 and 2.7×1019 cm−3, respectively, by Hall effect measurement. Furthermore, p-type poly-Ge/n-Ge and n-type poly-Ge/p-Ge junctions are formed with significant rectification ratios of 103 and 102@±2 V, respectively. These findings indicate that the low-temperature MIC approach holds great potential for the fabrication of n- and p-type poly-Ge, enabling the development of Ge-based active devices at low temperature.

A novel magnetohydrodynamic power generation system using low-temperature liquid metal coupled with a rectangular single-phase natural circulation loop

A novel magnetohydrodynamic power generation system using low-temperature liquid metal coupled with a rectangular single-phase natural circulation loop

Low-Temperature and Fast-Charge Sodium Metal Batteries.

Low-temperature operation of sodium metal batteries (SMBs) at the high rate faces challenges of unstable solid electrolyte interphase (SEI), Na dendrite growth, and sluggish Na+ transfer kinetics, causing a largely capacity curtailment. Herein, low-temperature and fast-charge SMBs are successfully constructed by synergetic design of the electrolyte and electrode. The optimized weak-solvation dual-salt electrolyte enables high Na plating/stripping reversibility and the formation of NaF-rich SEI layer to stabilize sodium metal. Moreover, an integrated copper sulfide electrode is in situ fabricated by directly chemical sulfuration of copper current collector with micro-sized sulfur particles, which significantly improves the electronic conductivity and Na+ diffusion, knocking down the kinetic barriers. Consequently, this SMB achieves the reversible capacity of 202.8mAhg-1 at -20°C and 1C (1C = 558mAg-1). Even at -40°C, a high capacity of 230.0mAhg-1 can still be delivered at 0.2C. This study is encouraging for further exploration of cryogenic alkali metal batteries, and enriches the electrode material for low-temperature energy storage.

An Ultrastable Low-Temperature Na Metal Battery Enabled by Synergy between Weakly Solvating Solvents.

The low ionic conductivity and high desolvation barrier are the main challenges for organic electrolytes in rechargeable metal batteries, especially at low temperatures. The general strategy is to couple strong-solvation and weak-solvation solvents to give balanced physicochemical properties. However, the two challenges described above cannot be overcome at the same time. Herein, we combine two different kinds of weakly solvating solvents with a very low desolvation energy. Interestingly, the synergy between the weak-solvation solvents can break the locally ordered structure at a low temperature to enable higher ionic conductivity compared to those with individual solvents. Thus, facile desolvation and high ionic conductivity are achieved simultaneously, significantly improving the reversibility of electrode reactions at low temperatures. The Na metal anode can be stably cycled at 2 mA cm-2 at -40 °C for 1000 h. The Na||Na3V2(PO4)3 cell shows the reversible capacity of 64 mAh g-1 at 0.3 C after 300 cycles at -40 °C, and the capacity retention is 86%. This strategy is applicable to other sets of weak-solvation solvents, providing guidance for the development of electrolytes for low-temperature rechargeable metal batteries.

Solvating lithium and tethering aluminium using di-coordination-strength anions for low-temperature lithium metal batteries

Di-coordination-strength anions can simultaneously solvate lithium and tether aluminium in low-temperature lithium metal batteries: the weakly coordinated anion exerts high ionic transport kinetics while the strongly coordinated anion stabilizes the aluminium surface.

Organohydrogel electrolytes with solvated structure regulation for highly reversible low-temperature zinc metal batteries

Organohydrogel electrolytes are prepared to improve the low-temperature performance of aqueous zinc-ion batteries by regulating Zn2+ solvation structures and hydrogen bonds between water and 1,3-dioxolane molecules.