Al Metal Research Articles

Unravelling stability of current collectors in lithium bis(trifluoromethanesulfonyl)imide salt and polyethylene oxide electrolyte for solid-state lithium batteries

Recent interest in solid-state lithium batteries prevails in the battery community because of their superiority in terms of safety concerns. Many works have been reported for electrodes and electrolytes and their suitability for solid-state polymer electrolytes to adopt in lithium batteries. Herein, for the first time, we report on the electrochemical stabilities of Cu and Al current collectors in a polyethylene oxide (PEO)-based solid-state electrolyte containing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. Our work on the electrochemical dynamic- and transient-mode polarization of these electrodes indicates that Cu metal undergoes Cu–O passivation below 3 V. The adhered Cu-F layer on the CuO passive layer may be beneficial to delay undesired reaction such as corrosion. And it is further confirmed that Al metal passivates stably even up to 5 V; namely, the Al surface forms double layers of the outer Al–F and inner Al–O layers. These F- and O-based layers are attributed to the combination of the Al and O from the reductively decomposed PEO and further progress of Al2O3 and HF (H+ + F− →HF), decomposed from the PEO (H+) and TFSI− (F−). Therefore, we verify that successful passivation on Cu and Al metal surfaces facilitates their suitability as current collectors for solid-state polymer lithium batteries.

Development of Iron Fluoride Based Nanocomposite Materials to Enable High Performance Aluminium-Ion Batteries

Developing grid-scale energy storage is important for the penetration of intermittent renewable energies such as wind and solar, but remains one of the biggest challenges in the field of electrochemical energy storage [1]. The application of mature lithium-ion batteries (LIBs) to grid energy storage is controversial due to the limited Li resources and geographical distribution, high cost of materials (e.g., Co, Li), limited lifetime, and safety concerns [2]. Rechargeable aluminium ion batteries (AIBs), which normally utilises aluminium (Al) metal as anode, are one of the most promising battery technologies for future large-scale energy storage, due to the high theoretical volumetric capacity (8046 mAh cm−3), high safety, and low cost and high abundance of aluminium (the third most abundant metal in the earth crust) [3].AIBs have achieved long cycle life (>7500 cycles) when using graphite and graphene as cathode materials [4-5]. Nevertheless, the reported graphite-based cathodes have intrinsically low storage capacities (60–200 mAh g-1) due to the intercalation mechanism of the solvated ions rather than the multivalent Al3+ transformation. Extensive efforts have been made to develop new cathode materials to promote the specific/volumetric capacity of AIBs, including transition metal oxides [6], sulfides [7], selenides [8] and others. These AIBs based on non-graphite cathodes usually demonstrate either low discharge voltage, or high initial capacity but significant capacity decay and poor cycle life. To further improve the performance of AIBs, new cathode materials with high storage capacity and long cycle life needs to be developed.In this paper, we report the development of a nanoscale FeF3@expaned graphite (EG) composite as a novel conversion-type cathode material for AIBs [9]. AIB coin cells were assembled using high-purity Al foil as the anode, the ionic liquid [EMIm]Cl/AlCl3 as the electrolyte, and the FeF3@EG composite as cathode. The conversion reaction between the Al3+ ions and FeF3 through transferring three electrons for per Al3+ ion reacted could boost the storage capacity of AIBs. A single-wall carbon nanotube-modified separator was introduced into the system, to significantly restrict the shuttle effect of the intermediate product of FeF3. The assembled AIBs exhibited a satisfactory reversible specific capacity of 266 mAh g-1 at a current density of 60 mA g-1 after 200 cycles, and a good Coulombic efficiency approaching 100% after 400 cycles at a current density of 100 mA g-1 [9]. Ex-situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) have been applied to explore the energy storage mechanism of FeF3 in AIBs for the first time [9].To further overcome the corrosion issue of ionic liquid, a gel polymer electrolyte (GPE) has been successfully synthesised via an innovative method where no solvent or initiator was utilised in the polymerisation process. The application of GPE significantly reduced the corrosivity and enhances the moisture sensitivity of EMIC ionic liquid, as well as improving the reversible ability of the AIBs. The FeF3@EG-based AIB with 0.8g-EMIC-gel electrolyte exhibits a reversible capacity of 204.5 mAh g-1after 1000 cycles at a current density of 100 mA g-1 and stable rate performance for 600 cycles with a Coulombic efficiency of approximately 95%.This work provides unprecedented insight into novel conversion type cathode materials for AIBs. The findings in this work can serve as guidance for the successful design of low cost and high discharge capacity AIBs for large-scale energy storage and are also meaningful for the fundamental understanding of the metal fluorides cathodes for AIBs.

Electrodeposition of Reactive Aluminum-Nickel Coatings in an AlCl3:[Emim]Cl Ionic Liquid Containing Nickel Nanoparticles

The electrodeposition of reactive aluminum-nickel dispersion coatings was performed by pulsed direct current (PDC) onto copper substrates in the ionic liquid 1.5:1 AlCl3:[EMIm]Cl (1-Ethyl-3-methylimidazolium chloride). A cathodic current density of 15 mA/cm2 was used with two different frequency (f)/duty cycle (r c) combinations, i.e., f= 0.33 Hz/ r c= 0.33 (t on= 1 s, t off= 2 s) and f= 0.05 Hz/ r c= 0.5 (t on= 10 s, t off= 10 s). Several electrochemical techniques like Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Open Circuit Potential measurements were used besides X-Ray Diffraction, Confocal Microscopy, Scanning Electron Microscopy, Atomic Absorption Spectroscopy and 27Al/1H Nuclear Magnetic Resonance in order to shed more light on the mechanism of Ni particle incorporation into the Al metal matrix. We could show that particle incorporation at the beginning of the deposition mainly takes place via particle adsorption at the substrate. As the thickness of the coating increases, it seems that the main mechanism for particle incorporation is via the reduction of Al2Cl7 - ions adsorbed at the particles surface. Three different Ni NPs concentration were tested in this work: 5, 10 and 20 g/L. Although a considerable high incorporation of Ni NPs has been achieved from the IL electrolyte containing the highest concentration of Ni NPs (i.e. ~ 33 wt.% from a 20 g/L of Ni NPs bath), a high concentration of NPs in the ionic liquid resulted having a negative effect in terms of quality of the coatings, due to local cathodic passivation, or solidification of the electrolyte in a poorly conductive compound. This phenomenon has been related to the increase in viscosity originating from the decrease in rotational mobility of the [EMIm]+ cation, as detected by 1H NMR. Despite this fact, almost equivalent amounts of Ni and Al (Ni ~ 45 wt.% and Al ~ 44 wt.%) have been detected by energy-dispersive X-ray spectroscopy mapping in some areas of the coatings prepared with longer pulse off-time (f = 0.05 Hz, t off= 10 s). Such a layer composition would be convenient for the targeted application. Nevertheless, more studies related to the homogeneity of the deposits, as well as ignition tests, must be performed to evaluate the suitability of the coatings to trigger a self-propagating reaction.

Addressing the Voltage and Energy Fading of Al-Air Batteries to Enable Seasonal/Annual Energy Storage

The European Commission's Strategic Energy Technology Plan (SET Plan-2018) aims to slow down anthropogenic global warming by 2030 and is seen as a crucial intermediate step to guarantee net-zero greenhouse gas emissions by 2050. Its achievement requires a significant increase in renewable energy. Various technologies have been proposed to solve this issue, including power-to-X options, i.e., converting renewable electricity into a storable form (e.g., hydrogen), and secondary-battery-based power-to-power options.1 Nonetheless, seasonal and even annual energy storage in a low-cost manner is still a challenge. In this context, employing the earth-abundant, low-cost, and easy to transport and store Al metal as the energy carrier may offer some valuable options, e.g., the combination of Al production via inert-electrode smelting (power to metal) and Al conversion to electricity via Al-air batteries (AABs, metal to power).2 However, voltage decay during discharge severely decreases the practical energy density of AABs, especially, upon long-term operation.3,4 ,5 Herein, the electrochemical behavior of AMA in KOH aqueous solutions containing various concentrations of dissolved aluminum, predominantly present as , is compared to investigate the impact of . It is observed that an increasing polarization of AMAs occurs even before any precipitate is generated on their surface. Further experimental and computational results reveal that the accumulation of greatly reduces the OH- concentration and, in turn, negatively affects the reaction kinetics. Therefore, the voltage decay issue of AABs is caused by the accumulation of in the electrolyte rather than Al(OH)3 on AMAs. Subsequently, it is demonstrated that seeded precipitation of in the electrolytes to Al(OH)3 precipitate with releasing OH- via utilizing its lower solubility at 20 °C than at 50 °C allows effective recovery of the potential of AMAs and the voltage of AABs. At last, prototype AABs are assembled and tested to evaluate the feasibility of voltage recovery via the proposed seeded precipitation process. References (1) Ersoy, H.; Baumann, M.; Barelli, L.; Ottaviano, A.; Trombetti, L.; Weil, M.; Passerini, S. Hybrid Energy Storage and Hydrogen Supply Based on Aluminum—a Multiservice Case for Electric Mobility and Energy Storage Services. Adv. Mater. Technol. 2022, 7 (8), 2101400.(2) Baumann, M.; Barelli, L.; Passerini, S. The Potential Role of Reactive Metals for a Clean Energy Transition. Adv. Energy Mater. 2020, 10 (27), 1–8.(3) Zhang, P.; Xue, J.; Liu, X.; Wang, Z.; Li, X.; Jiang, K. Electrochimica Acta Improving Energy Efficiency of Commercial Aluminum Alloy as Anodes for Al-Air Battery through Introducing Micro-Nanoscale AlSb Precipitates. Electrochim. Acta 2022, 417, 140331.(4) Wu, P.; Zhao, Q.; Yu, H.; Tang, Z.; Li, Y.; Huang, D.; Sun, D.; Wang, H.; Tang, Y. Modification on Water Electrochemical Environment for Durable Al-Air Battery: Achieved by a Low-Cost Sucrose Additive. Chem. Eng. J. 2022, 438, 135538.(5) Liu, S.; Ban, J.; Shi, H.; Wu, Z.; Shao, G. Near Solution-Level Conductivity of Polyvinyl Alcohol Based Electrolyte and the Application for Fully Compliant Al-Air Battery. Chem. Eng. J. 2022, 431 (P3), 134283.

Enhancement of CO2 adsorption performance and widening of adsorption temperature window by co-doping different valence state metals on the Li4SiO4 (010) surface

Lithium silicate (Li4SiO4) has good stability, high theoretical carbon dioxide (CO2) adsorption capacity, and low regeneration temperature. It has great potential in the field of CO2 adsorption. However, it is difficult to achieve the theoretical value in practical applications and a narrow temperature window for adsorption. Therefore, further research in this area is urgently needed. In this study, experimental and simulation methods were used to investigate the effects of single doping and co-doping with K, Na, Be, Ca, and Al metals on the adsorption performance and adsorption temperature window of Li4SiO4. Single doping with K, Na, or Al makes CO2 easier to be adsorbed on the Li4SiO4 (010) surface by increasing the charge transfer from the Li4SiO4 surface to CO2. Co-doping with K and Al increases the adsorption energy of CO2 on the Li4SiO4 (010) surface, enhances hybrid peaks, and broadens the temperature range for CO2 adsorption on the Li4SiO4 surface. It exhibits stable cyclic adsorption performance under low CO2 (15% CO2, N2 balance) concentration, and more electron transfer facilitates the formation of carbonate species on the Li4SiO4 (010) surface at lower temperatures, thereby improving its CO2 adsorption performance.

High-efficiency radiation attenuation shields of polymer composites for the low earth orbit space environment – multilayer shielding simulation system-based investigations

The polymer/metal hybrids have been used as a solution for the mitigation of ionizing radiation in space for sensitive electronics components, particularly for a proton-rich Low Earth Orbit (LEO) environment. Consequently, radiation attenuation analysis of polymer/metal hybrid composites has been investigated. Radiation attenuation analysis has been performed using online GEANT4 (simulation toolkit) and the Multilayer Shielding Simulation System (MULASSIS) for the LEO space environment. The shielding potential of polymers, such as poly(dimethyl siloxane), poly(methyl methacrylate), polyurethane and ultra-high molecular weight polyethylene, were analyzed with optimized compositions. It was observed that the pristine PDMS attenuated relatively more radiations than other polymer matrices. For modelling of hybrid radiation material composition, PDMS and carbon fibre fabric-derived composite laminates along with metal sheets (Aluminum Al, Tantalum Ta or Tungsten W) were used to analyze hybrid compositions. Here, hybrid composition performance was analyzed as a function of various areal densities. Analyzed polymer laminate/metal hybrid compositions performed better to attenuate LEO radiations up to 42.29%, compared to conventional Al (areal densities of 0.2–1.0 g/cm2). The maximum magnitude of attenuation was found at an areal density of 1.0 g/cm2 for Ta and W metal composition (39.44% and 42.29%, respectively), and so performed better than Al metal. Improved attenuation ratios of the hybrid compositions revealed that the hybrid laminate/metal shields can replace conventional Al shields towards LEO space radiations.

Enhancement of antimicrobial properties by metals doping in nano-crystalline hydroxyapatite for efficient biomedical applications

In this study, we have introduced a method for the synthesis of various metal-doped nano-crystalline hydroxyapatites (HAp) using a standard wet chemical precipitation technique. Both divalent (Ni and Zn) and trivalent (Al and Fe) metals were selected for the doping process. Additional research work was also conducted to assess the antimicrobial efficacy of these doped-HAps against a range of gram-positive and gram-negative microorganisms. All the synthesized metal-doped hydroxyapatite (HAp) exhibited notable antibacterial characteristics against gram-negative bacterial strains, namely Escherichia coli (E. coli) and Salmonella typhi (S. typhi), outperforming the pure HAp. The inhibition zone observed for the metal-doped HAp ranged from 14 to 16 mm. The Fe ion displayed a notable inhibitory zone measuring 16 mm, proving to be the most expansive among all tested ions against both E. coli and S. typhi bacterial strains. The Zn-HAp exhibited a comparable inhibitory zone size of 14 mm against both S. typhi and E. coli. Additional characterization methods, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and Scanning electron microscopy (SEM), were used to validate the structural properties of the synthesized metal-doped hydroxyapatite (HAp) samples. The biocompatibility assessment of metal-doped hydroxyapatite (HAp) samples was carried out by haemolysis tests, which revealed that all synthesized hydroxyapatite (HAp) samples have the potential to serve as reliable biomaterials.

Enhancing NaBH4 regeneration using an Al-rich alloy

Onsite hydrogen generation by sodium borohydride hydrolysis resolves hydrogen energy supply system challenges. However, the spent-NaBH4 regeneration is still a problem in the closed loop of this irreversible reaction. As the by-product is the key to the problem, NaB(OH)4 is regarded as not the boron source but the hydrogen source of NaBH4 regeneration. Therefore, in this study, inexpensive Al metal and NaB(OH)4 are ball milled under argon to regenerate NaBH4 without additional hydrogen input. However, the ball-milling reaction is hindered by the flexible Al and impact oxide layer, and the NaBH4 yield is only approximately 22 %. Therefore, a brittle intermetallic compound Mg2Al3 is reacted with NaB(OH)4 by ball milling, achieving a NaBH4 yield of over 42 %. The mechanism study shows that the brittleness of the raw material plays an important role in promoting the ball-milling reaction. This study achieves NaBH4 regeneration using only Al as the reducing agent and provides a promising method to promote the mechanochemical regeneration of NaBH4.

Manipulating the corrosion homogeneity of aluminum anode toward long‐life rechargeable aluminum battery

AbstractAluminum metal batteries are considered to be promising secondary batteries due to their high theoretical specific capacity. However, metallic aluminum suffers from corrosion, pulverization, and crushing problems in nonaqueous electrolytes. Constructing a solid‐electrolyte interphase layer on the anode electrode has been confirmed to be the key to improving the cycling performance of rechargeable batteries. Herein, we demonstrate an Al metal anode with a physical protective layer achieved by a simple blade coating method. This modified Al metal anode demonstrates ultra‐low voltage hysteresis (~25 mV at 0.1 mA cm−2 and ~30 mV at 1 mA cm−2), and superior stability (630 h at 0.1 mA cm−2 and 580 h at 1 mA cm−2). When coupling this anode with flake graphite cathode, the assembled full cells exhibit superior cycling stability (92 mAh g−1 maintained after 740 cycles at 0.1 A g−1). The current work presents a promising approach to stabilize Al metal anodes for next‐generation rechargeable aluminum batteries.

MXene-Based Mixed Conductor Interphase for Dendrite-Free Flexible Al Organic Battery.

Al batteries are promising post-Li battery technologies for large-scale energy storage applications owing to their low cost and high theoretical capacity. However, one of the challenges that hinder their development is the unsatisfactory plating/stripping of the Al metal anode. To circumvent this issue, an ultrathin MXene layer is constructed on the surface of Al by in situ chemical reactions at room temperature. The as-prepared flexible MXene film acts like armor to protect the Al-metal by its high ionic conductivity and high mechanical flexibility. The MXene endow the Al anode with a long cyclic life of more than 5000 h at ultrahigh current density of 50 mA cm-2 for Al//Al batteries and a retention of 100% over 200 cycles for 355 Wh kg-1 PTO//Al batteries. This work provides fresh insights into the formation and regulation of stable electrode-electrolyte interfaces as well as effective strategies for improving Al metal batteries.

Dual-Functional Electrochromic Smart Window Using WO3·H2O-rGO Nanocomposite Ink Spray-Coated on a Low-Cost Hybrid Electrode.

Electrochromic windows have gained growing interest for their ability to change their optical state in the visible and NIR ranges with minimal input power, making them energy-efficient. However, material processing costs, fabrication complexity, and poor electrochromic properties can be barriers to the widespread adoption of this technology. To address these issues, electrochromic material and fabrication processes are designed to realize their potential as a cost-effective and energy-efficient technology. In this work, an electrochromic composite material-based ink is synthesized consisting of WO3·H2O nanoplates supported on rGO (reduced graphene oxide) nanosheets (WH-rGO), wherein an optimized amount of rGO (0.05 to 0.5 wt %) is introduced for providing a higher conduction pathway for efficient charge transport without sacrificing the electrochromic performance of WO3·H2O nanoplates. The stable ink dispersion prepared in the study is deposited by spray coating on transparent conducting electrodes over large areas (25 cm2). The WH-rGO nanocomposite (0.4 wt %) results in 43% optical modulation at 700 nm, with bleaching and coloration times of 6 and 8 s, respectively. Interestingly, the device also possesses an electrochemical energy storage capability with an areal capacitance of 16.3 mF/cm2. The electrochromic composite material is successfully translated on tin doped indium oxide (ITO)-coated Al metal mesh hybrid electrodes (T = 80%, Rs = 40 Ω/□) to replace ITO. Finally, an electrochromic device of 5 × 5 cm2 is fabricated by spray-coating the ink on cost-effective ITO/Al-mesh hybrid electrodes. The device displays blue to colorless modulation with an excellent bleaching time of 0.43 s and a coloration time of 2.16 s, making it one among the fast-operating devices fabricated by complete solution processing. This work showcases the economical production of a dual-function electrochromic device, which can be a feasible option as an alternative to existing ITO-based devices in both automotive and infrastructure applications.

Stable Aluminum Metal Anode Enabled by Dual-Functional Molybdenum Nanoparticles.

Constructing robust anode with strong aluminophilicity and rapid desolvation kinetics is essential for achieving high utilization, long-term durability, and superior rate performance in Al metal-based energy storage, yet remains largely unexplored. Herein, molybdenum nanoparticles embedded onto nitrogen-doped graphene (Mo@NG) are designed and prepared as Al host to regulate the deposition behavior and achieve homogeneous Al plating/stripping. The monodispersed Mo nanoparticles reduce the desolvation energy barrier and promote the deposition kinetics of Al. Additionally, Mo nanoparticles act as aluminophilic nucleation sites to minimize the Al nucleation overpotential, further guiding uniform and dense Al deposition. As a result, the dual-functional Mo@NG endows Al anodes with low voltage hysteresis, reversible Al plating/stripping with high coulombic efficiency, and excellent high-rate capability under 5mA cm-2. Moreover, the as-designed Al metal full batteries deliver a high capacity retention of 92.8% after 3000 cycles at 1 A g-1. This work provides an effective solution to optimize the electrochemical properties of Al metal anode from the perspective of desolvation and deposition reactions, towards the development of high-safety and long-cycling aluminum-ion batteries.

Correlation of sputtering power with microstructure and ionic conductivity in lithium aluminum oxide thin films prepared by reactive co-sputtering

Li–Al–O thin films synthesized via the reactive magnetron co-sputtering have the potential to act as solid-state electrolytes in micro-batteries. In this paper, the constant RF power (155 W) and variable DC power (20–50 W) were applied to lithium (Li) and aluminum (Al) metal targets, respectively, in Ar/O2 atmosphere to produce films with adequate ionic conductivity. The influence of DC sputtering power on the composition, microstructure, band gap energy, ionic conductivity, and dielectric loss of films were studied in detail. X-ray photoelectron spectroscopy (XPS) showed a shift of the Li 1s peak towards higher binding energy with increasing DC power. X-ray diffraction (XRD) spectra confirmed the amorphous state for all as-deposited films, while the post-annealed films at 950 °C contain the γ-LiAlO2 phase. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) images revealed that the increasing DC power had a significant impact on the film morphology, enlarging grain size and increasing surface roughness. Energy dispersive X-ray (EDX) spectroscopy showed that increasing the DC power increased the Al content. The optical properties were examined by ultraviolet–visible (UV–vis) spectroscopy, which indicated that increasing the Al content led to a blue shift of the absorption edge and an increase in the band gap energy (5.40–5.68 eV). Increasing the DC power resulted in an improvement of room-temperature conductivity by two orders of magnitude (∼2.85 × 10−9 S cm−1) and a decrease in the activation energy from 0.54 eV to 0.32 eV. These results suggest that composition and microstructure significantly affect the ionic transport in co-sputtered Li–Al–O films.

The effect of thickness and surface roughness on the absorption coefficient (α) of Aluminum (Al)

Noise is an essential factor in determining various interior elements and machinery, especially those made of metal. The noise level generated by metal is caused by the low level of sound attenuation factor, known as the absorption coefficient (alpha, α) of the metal. Aluminum (Al) metal has the characteristics of corrosion resistance, lightweight, attractive color, and ease of form, so it is popular as a material for various households, machinery, and industrial machinery. This study explains the effect of surface roughness (0.05, 0.12, and 0.15 Ra) and thickness (2, 4, and 6 mm) of Al specimens on the measurement values of absorption coefficient (α). The measurements result show that the average value of α is relatively stable by variations in surface roughness and thickness within the low to medium frequency range (200-800 Hz). Although in general there are increased α values for the high-frequency ranges (1000-1200 Hz), the lowest average of α value occurs in the specimen with the highest surface roughness of Ra 25. Thus, even though the variation in thickness has no significant effect on the α value, the higher surface roughness of Al will reduce the value of the absorption coefficient (α) resulting in higher noise generated.

An Aqueous Rechargeable Al‐Ion Battery Based on Cobalt Hexacyanoferrate and Al Metal

AbstractLike other aqueous batteries, aqueous rechargeable Al‐ion batteries (ARAIBs) have attracted much attention due to their high safety and low cost. However, the low energy density of ARAIBs limits its popularization and application. In order to solve this problem, in addition to choosing Al metal as the negative electrode, it is also necessary to choose a suitable positive electrode material. Here, a cubic phase cobalt hexacyanoferrate (CoHCF) with excellent rate and cycling performance is used as the positive electrode material. Due to the reversible catalysis of the Cl−/Cl0 reaction at high potential in saturated AlCl3 solution, it has the characteristics of high capacity up to 103.5 mAh g−1. Combined with the Al metal as negative electrode, an ARAIB with an average discharge voltage of 1.56 V and an energy density of 155 Wh kg−1 is constructed, which shows outstanding cycling and rate performances.

Solvation Sheath Engineering by Multivalent Cations Enabling Multifunctional SEI for Fast-Charging Lithium-Metal Batteries.

With the pursuit of high energy and power density, the fast-charging capability of lithium-metal batteries has progressively been the primary focus of attention. To prevent the formation of lithium dendrites during fast charging, the ideal solid electrolyte interphase should be capable of concurrent fast Li+ transport and uniform nucleation sites; however, its construction in a facile manner remains a challenge. Here, as Al3+ has a higher charge and Al metal is lithiophilic, we tuned the Li+ solvation structure by introducing LiNO3 and aluminum ethoxide together, resulting in the dissolution of LiNO3 and the simultaneous generation of fast ionic conductor and lithiophilic sites. Consequently, our approach facilitated the deposition of lithium metal in a uniform and chunky way, even at a high current density. As a result, the Coulombic efficiency of the Li||Cu cell increased to over 99%. Moreover, the Li||LiFePO4 full cell demonstrated significantly enhanced cycling performance with a remarkable capacity retention of 94.5% at 4 C, far superior to the 46.1% capacity retention observed with the base electrolyte.

Investigating surface wear characteristics of single-crystal SiC based on metal electrochemical corrosion

Aiming at the environmental pollution of the polishing solution in chemical mechanical polishing, this study introduces a chemical mechanical polishing technique for single-crystal SiC based on metal electrochemical corrosion. The wear properties of the SiC C-surface, as influenced by different materials on grinding balls (Cu, Fe, Al, and Al2O3), and different solutions (KCl, Na2SO4, Fenton, and H2O), were examined through wear experiments to elucidate the material removal mechanisms involved. The experiments demonstrated that the most significant wear marks, with a peak cross-sectional area of 46.89 μm2, were obtained when the C-face of SiC was ground with Al-paired grinding balls in an Na2SO4 electrolyte solution. Energy dispersive spectroscopy analysis of the wear debris revealed an O elemental content of 11 %, and X-ray photoelectron spectroscopy analysis indicated the existence of SiO2 and Al2O3 oxides. Subsequently, the effects of Na2SO4 solution concentration and pH on the wear pattern of the C-surface were investigated. The largest wear cross-sectional area (approximately 50 μm2) was observed when using an Na2SO4 electrolyte solution with a concentration of 1.25 mol/L at a pH of 9 in an alkaline solution. The proposed mechanism of material removal in single-crystal SiC via metal electrochemical corrosion involves the Al metal acting as a cathode. This causes galvanic coupling corrosion, generating a corrosion current, which subsequently induces oxidation of the SiO2 oxide layer on the anode SiC surface. The oxidized layer is then mechanically removed.

Modification of Al Surface via Acidic Treatment and its Impact on Plating and Stripping.

Amorphous Al2 O3 film that naturally exists on any Al substrate is a critical bottleneck for the cyclic performance of metallic Al in rechargeable Al batteries. The so-called electron/ion insulator Al oxide slows down the anode's activation and hinders Al plating/stripping. The Al2 O3 film induces different surface properties (roughness and microstructure) on the metal. Al foils present two optically different sides (shiny and non-shiny), but their surface properties and influence on plating and stripping have not been studied so far. Compared to the shiny side, the non-shiny one has a higher (~28 %) surface roughness, and its greater concentration of active sites (for Al plating and stripping) yields higher current densities. Immersion pretreatments in Ionic-Liquid/AlCl3 -based electrolyte with various durations modify the surface properties of each side, forming an electrode-electrolyte interphase layer rich in Al, Cl, and N. The created interphase layer provides more tunneling paths for better Al diffusion upon plating and stripping. After 500 cycles, dendritic Al deposition, generated active sites, and the continuous removal of the Al metal and oxide cause accelerated local corrosion and electrode pulverization. We highlight the mechanical surface properties of cycled Al foil, considering the role of immersion pretreatment and the differences between the two sides.

Effect of tooltip profile and tilt angle on Al8090-TiH2/Al2O3 foam and its mechanical characterization

Metal foams are used for industrial purposes because of their lightweight structure, high specific modulus of elasticity, and excellent energy-absorbing capacity. Various techniques have been used for the development of metal foam. In the present study, Al8090 foam is fabricated by the uniform mixing of TiH2/Al2O3 particles with the help of the stirring action of the tool probe. The groove cutting method is used to prepare the Al metal matrix and friction stir processing is performed over the grooves for even dispersion of the blowing powder to produce the precursor of the localized aluminium (Al) foam. Special purpose inclined fixtures with different angles are fabricated to produce tilt on the three-axis vertical machining centre. Three different tip profiles, namely plane cylindrical, threaded cylindrical and square are selected for processing along with the fixture plate angle set at three levels of 1°, 1.5° and 2.5°. Tool rotational and traversing speed rate is kept constant and its influence has been assessed on the foam's porosity, hardness and compressive strength. Scanning electron microscopy and energy-dispersive X-ray spectroscopy tests have also been performed to analyse the foam's morphology and found that the square tip pin with 1.5° fixture plate angle has the best mechanical properties.

Al and other critical metals co-extraction from coal gangue through delamination pretreatment and recycling strategies

Coal gangue is an underused resource and there is a lack of its utilization in the green economy. This work aims at the clean recovery of critical metals in coal gangue, with the development of a recycling extraction process through repeated utilization of ammonia and ammonium salts, and development of delamination pretreatment methods to improve the extraction efficiency in relation to structural characteristics of aluminosilicate minerals in coal measures. The results showed that the pretreatment could replace the powder process, significantly improve the extraction efficiency and, simultaneously, inhibit the leaching of harmful elements. The leaching rates of Al, Li and Ga can be increased to 62.74%, 86.56%, and 46.18%, respectively, while the leaching of Pb was inhibited. Polymetallic products are potential raw materials for low-cost composite materials. The study developed and optimized a set of new ideas to promote the green extraction and utilization of critical metals in coal gangue.