Nonaqueous Aluminum Research Articles

D-Orbital Induced Electronic Structure Reconfiguration toward Manipulating Electron Transfer Pathways of Metallo-Porphyrin for Enhanced AlCl2 + Storage.

The positive electrodes of non-aqueous aluminum ion batteries (AIBs) frequently encounter significant issues, for instance, low capacity in graphite (mechanism: anion de/intercalation and large electrode deformation induced) and poor stability in inorganic positive electrodes (mechanism: multi-electron redox reaction and dissolution of active materials induced). Here, metallo-porphyrin compounds (employed Fe2+, Co2+, Ni2+, Cu2+, and Zn2+ as the ion centers) are introduced to effectively enhance both the cycling stability and reversible capacity due to the formation of stable conjugated metal-organic coordination and presence of axially coordinated active sites, respectively. With the regulation of electronic energy levels, the d-orbitals in the redox reactions and electron transfer pathways can be rearranged. The 5,10,15,20-tetraphenyl-21H,23H-porphine nickle(II) (NiTPP) presents the highest specific capacity (177.1 mAh g-1), with an increment of 32.1% and 77.1% in comparison with the capacities of H2TPP and graphite, respectively, which offers a new route for developing high-capacity positive electrodes for stable AIBs.

Locally Concentrated Deep Eutectic Liquids Electrolytes for Low-Polarization Aluminum Metal Batteries.

Low-cost and nontoxic deep eutectic liquid electrolytes (DELEs), such as [AlCl3]1.3[Urea] (AU), are promising for rechargeable non-aqueous aluminum metal batteries (AMBs). However, their high viscosity and sluggish ion transport at room temperature lead to high cell polarization and low specific capacity, limiting their practical application. Herein, non-solvating 1,2-difluorobenzene (dFBn) is proposed as a co-solvent of DELEs using AU as model to construct a locally concentrated deep eutectic liquid electrolyte (LC-DELE). dFBn effectively improves the fluidity and ion transport without affecting the ionic dynamics in the electrolyte. Moreover, dFBn also modifies the solid electrolyte interphase growing on the aluminum metal anodes and reduces the interfacial resistance. As a result, the lifespan of Al/Al cells is improved from 210 to 2000h, and the cell polarization is reduced from 0.36 to 0.14V at 1.0mAcm-2. The rate performance of Al-graphite cells is greatly improved with a polarization reduction of 0.15 and 0.74V at 0.1 and 1Ag-1, respectively. The initial discharge capacity of Al-sulfur cells is improved from 94 to 1640mAhg-1. This work provides a feasible solution to the high polarization of AMBs employing DELEs and a new path to high-performance low-cost AMBs.

Tin oxide quantum dots embedded between graphene sheets to improve non-aqueous aluminum ion battery performance

A composite of tin oxide quantum dots (SnO2QDs) and reduced graphene oxide (RGO), was synthesized using the rapid microwave synthesis method and used as cathode material in the non-aqueous aluminum ion battery. In addition, graphene oxide (GO) and RGO were also prepared separately, and the properties of the resulting cathode materials were compared using XRD, FESEM, Raman, and HRTEM. RGO/SnO2QDs, GO, and RGO were mixed separately with a binder at a ratio of 90:10 and the resulting slurries were coated on a graphite sheet. The electrochemical performance of the graphite sheet, GO, RGO, and RGO/SnO2QDs cathodes was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge tests in an electrochemical cell containing an ionic liquid (AlCl3/Et3NHCl) as an electrolyte and aluminum as an anode. The battery with RGO/SnO2QDs cathode exhibited an excellent specific discharge capacity of 231 mAh g−1 at 2 A g−1 after 300 cycles with a Coulomb efficiency of 98.3 %. Furthermore, after 25,000 charge and discharge cycles at 2.5 A g−1, the Al||RGO/SnO2QDs battery demonstrated a specific discharge capacity of 163 mAh g−1, with a Coulombic efficiency of 89 %. Additionally, the superior battery also displayed impressive speed performance, achieving a specific discharge capacity of 124.6 mAh g−1 at 4 A g−1, with a Coulombic efficiency of 98.6 %. A comparison of the results of four prepared batteries showed that the synergistic effect of SnO2QDs and RGO layers makes for a suitable cathode material for rechargeable aluminum-ion batteries.

Hybridization of Carbon Nanotube Tissue, MnO2 Catalyst and CFx as an Advanced Air Cathode in Metal–Air Batteries

We first present the utilization of hybrid carbon nano-tube (CNT) – manganese dioxide (MnO2) tissues as air electrodes in nonaqueous aluminum- and lithium-based battery systems. The CNT tissues are impregnated with α-manganese dioxide nanoparticles via a straightforward binder-free ultrasonic treatment, thereby enabling an improved oxygen reduction reaction (ORR) catalytic activity. Half-cell potentiodynamic measurements along with full-cell discharge evaluations of Li- and Al-based battery systems are reported. Higher discharge potentials and capacities were obtained from generic and advanced hybrid CNT–MnO2 air cathodes. The discharge products obtained on the air cathode surface were studied using high-resolution scanning electron microscopy. Their chemical compositions were evaluated using elemental mapping energy-dispersive X-ray spectroscopy. The stability of the α-MnO2 catalyst was studied using X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy, thereby indicating the ongoing formation of an outer MnF2 shell layer, which affected the α-MnO2 functionality, as an efficient ORR catalyst. We conclude this part of the talk by showing that the function of the metal–air battery is enabled by using porous carbon nanotube (CNT)-based tissue substrates loaded with MnO2 catalyst.In contrast, fluorinated graphite (CFx) coating on the CNT substrate provides an additional discharge process, enhancing discharge capacity. Two CFx loadings are investigated, and their performances are compared with that of a pristine CNT tissue. Electrochemical evaluations, including half- and full-cell measurements, are performed to examine the effect of the coating layer thickness on the ability of the cell to function at high discharge rates.

Aluminum Alloys as Anodes for Aluminum Batteries

The development of batteries based on metals alternative to Lithium (e.g. Na, Mg, Zn, Al) requires the investigation of new electrodes and electrolytes. [1,2].This is particularly true in the case of non-aqueous Aluminum batteries which typically include a pure (>99.8%) Aluminum anode which: a) suffer of poor cycling stability and low coulombic efficiency; b) is particularly subjected to dendrite growth; c) can undergo to corrosion phenomena upon cycling; and d) show a poor compatibility toward chloroaluminated electrolytes [3].In this regard, the development of Aluminum alloys, alternative to pure Al anodes, is a challenging task which is barely investigated in the field of Aluminum ion batteries and requires experience in both battery electrochemistry and Aluminum metallurgy and casting.In this scenario, the proposed work investigates the synthesis and characterization of ternary Aluminum, alloys comprising Si, Ti and B as alloying elements, as anodes for Al-ion batteries [4]. Deposition/stripping measurements, impedance spectroscopy, metallographic analysis, EDXS and XRD techniques unveil the complex interplay existing between the microstructures of the alloys and the obtained electrochemical performance. It is demonstrated that a remarkable improvement in the: a) oxidation/reduction currents and overvoltages; and b) interfacial stability with the electrolyte; can be obtained, with respect to a conventional Al anode. Results allow to demonstrate that the investigation of Aluminum alloys can be crucial for the development of future Aluminum batteries.[1] F Bertasi, C Hettige, F Sepehr, X Bogle, G Pagot, K Vezzù, E Negro, S J Paddison, S G Greenbaum, M Vittadello, V Di Noto, ChemSusChem, 2015, 8 (18), 3069-3076[2] F Bertasi, F Sepehr, G Pagot, SJ Paddison, V Di Noto, Advanced Functional Materials 2016, 26 (27), 4860-4865[3] Y Zhang, S Liu, Y Ji, J Ma, H Yu, Advanced Materials 2018, 30 (38), 1706310[4] Italian Patent Application n° 102022000024522

Hybridization of carbon nanotube tissue and MnO2 as a generic advanced air cathode in metal–air batteries

This paper presents the utilization of hybrid carbon nano-tube (CNT) – manganese dioxide (MnO2) tissues as air electrodes in nonaqueous aluminum- and lithium-based battery systems. The CNT tissues are impregnated with α-manganese dioxide nanoparticles via a straightforward binder-free ultrasonic treatment, thereby enabling an improved oxygen reduction reaction (ORR) catalytic activity. Half-cell potentiodynamic measurements along with full-cell discharge evaluations of Li- and Al-based battery systems are reported. Higher discharge potentials and capacities were obtained from generic and advanced hybrid CNT–MnO2 air cathodes. The discharge products obtained on the air cathode surface were studied using high-resolution scanning electron microscopy. Their chemical compositions were evaluated using elemental mapping energy-dispersive X-ray spectroscopy. We complemented our analysis with density functional theory calculations of oxygen adsorption on MnO2 and graphene. The modifications obtained for the discharge products in both systems, along with their improved distribution within the cathode surface, supported longer discharge processes without clogging the O2 penetration pathways at the air cathode. The stability of the α-MnO2 catalyst was studied using X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy, thereby indicating the ongoing formation of an outer MnF2 shell layer, which affected the α-MnO2 functionality, as an efficient ORR catalyst.

Synergistic air electrode combining carbon nanotube tissue and fluorinated graphite material in hybrid nonaqueous aluminum batteries

Synergistic air electrode combining carbon nanotube tissue and fluorinated graphite material in hybrid nonaqueous aluminum batteries

Surface Evolution of Aluminum Electrodes in Non-Aqueous Aluminum Batteries

Aluminum batteries are considered as novel devices for safe energy storage. However, there is still a lack of understanding of the operation mechanism and evolution behaviors inside the cells of the current aluminum batteries, which limits the rational design and fabrication of high-performance aluminum batteries. To address the issue, systematical studies were applied to understand the surface evolution of the aluminum electrode in the aluminum batteries. Using in situ optical observation and simulation methods, the results suggest that dendrite growth and deposition on the aluminum electrode surface is critical to the aluminum deposition/corrosion evolution during following cycles, which leads to uneven current distribution on the electrode and inhomogeneous ion concentration interface. Additionally, the activity of the aluminum dendrites suggests that the nanosized aggregation would present less activity than the pristine aluminum, which in turn impacts the uniform evolution of the electrode surface. The aluminum-graphite full cells also exhibit a similar trend that is found in the in situ symmetric cells. The combined results from in situ optical observation, simulation, and full cell evaluation provide a deep insight into the aluminum batteries, which would be meaningful to guide research on their life cycle and evolution.

Nonmetal Current Collectors: The Key Component for High-Energy-Density Aluminum Batteries.

As one of the emerging safe energy-storage devices with high energy-to-cost ratio, nonaqueous aluminum batteries with enhanced energy density are intensively pursued by researchers. Although significant progress has been made on positive electrode materials, the effective energy density of aluminum batteries is still limited by the presence of high-density refractory metal current collectors, which are known to be electrochemically inert in highly acidic ionic-liquid electrolytes. To address such critical issues, here, a novel low-density (<2 g cm-3 ) nonmetal current collector is presented, which uses poly(ethylene terephthalate) (PET) substrates coated with indium tin oxide (ITO), with the purpose of significantly reducing the ratio of nonactive components in the electrodes. In addition to the excellent chemical and electrochemical stability (with voltage as high as ≈2.75 V vs Al3+ /Al), this nonmetal current collector, also encompassing a carboxymethyl cellulose (CMC) binder, allows as-assembled pouch cells to deliver a reversible specific capacity of ≈120 mAh g-1 at a current density of 50 mA g-1 . In comparison with the high-density refractory metal Mo or Ta current collectors, these nonmetal current collectors offer a novel strategy for constructing high-energy-density aluminum batteries by substituting the key components, with the aim of boosting the energy density of nonaqueous aluminum batteries.

Nonaqueous Aluminum Ion Batteries: Recent Progress and Prospects

Aluminum-ion batteries (AIBs) have been a promising energy storage technology beyond lithium-ion batteries (LIBs) benefiting from the high volumetric capacity and low cost of Al metal anode. As the...

Emerging Nonaqueous Aluminum-Ion Batteries: Challenges, Status, and Perspectives.

Aluminum-ion batteries (AIBs) are regarded as viable alternatives to lithium-ion technology because of their high volumetric capacity, their low cost, and the rich abundance of aluminum. However, several serious drawbacks of aqueous systems (passive film formation, hydrogen evolution, anode corrosion, etc.) hinder the large-scale application of these systems. Thus, nonaqueous AIBs show incomparable advantages for progress in large-scale electrical energy storage. However, nonaqueous aluminum battery systems are still nascent, and various technical and scientific obstacles to designing AIBs with high capacity and long cycling life have not been resolved until now. Moreover, the aluminum cell is a complex device whose energy density is determined by various parameters, most of which are often ignored, resulting in failure to achieve the maximum performance of the cell. The purpose here is to discuss how to further develop reliable nonaqueous AIBs. First, the current status of nonaqueous AIBs is reviewed based on statistical data from the literature. The influence of parameters on energy density is analyzed, and the current situation and existing problems are summarized. Furthermore, possible solutions and concerns regarding the construction of reliable nonaqueous AIBs are comprehensively discussed. Finally, future research directions and prospects in the aluminum battery field are proposed.

Aluminum Chloride-Graphite Batteries with Flexible Current Collectors Prepared from Earth-Abundant Elements.

In the search for low‐cost and large‐scale stationary storage of electricity, nonaqueous aluminum chloride‐graphite batteries (AlCl3‐GBs) have received much attention due to the high natural abundances of their primary constituents, facile manufacturing, and high energy densities. Much research has focused on the judicious selection of graphite cathode materials, leading to the most notable recent advances in the performance of AlCl3‐GBs. However, the major obstacle to commercializing this technology is the lack of oxidatively stable, inexpensive current collectors that can operate in chloroaluminate ionic liquids and are composed of earth‐abundant elements. This study presents the use of titanium nitride (TiN) as a compelling material for this purpose. Flexible current collectors can be fabricated by coating TiN on stainless steel or flexible polyimide substrates by low‐cost, rapid, scalable methods such as magnetron sputtering. When these current collectors are used in AlCl3‐GB coin or pouch cells, stable cathodic operation is observed at voltages of up to 2.5 V versus Al3+/Al. Furthermore, these batteries have a high coulombic efficiency of 99.5%, power density of 4500 W kg−1, and cyclability of at least 500 cycles.

Rechargeable Nonaqueous Aluminum Sulfur Battery

Rechargeable aluminum batteries attracted growing attentions in recent years as one candidate beyond lithium ion battery system. This is due to the great potential of aluminum metal anode owing to its high capacity (2.98 Ah/g and 8.05 Ah/cc), its negative electrochemical potential (-1.67 V vs. NHE), and its highest abundancy among metals in earth crust. Moreover, aluminum has significantly lower reactivity towards moisture and air compared to Li, Na and Mg. Reversible Al deposition/stripping in room temperature is extremely challenging due to the tendency of Al to form real passivation on its surface with both poor ionic and electronic conductivity. Nevertheless, use of aluminum anode was shown to be possible by in ionic liquid based electrolyte (RTIL-AlCl3) with up to 100% coulombic efficiency for aluminum deposition/stripping. As a high capacity cathode material (1,675 mAh/g), sulfur has attracted intense interest in Li/S, Mg/S and Na/S systems. A rechargeable Al/S battery is also of great interest because the full cell capacity could achieve 1072 mAh/g-(total electrode mass) and voltage could achieve ~1.25 V, estimated from the Gibbs formation energy of Aluminum sulfide( -724 kJ/mol). The gravimetric energy density is hence 1340 Wh/kg, over three times of a commercial LiCoO2/graphite cell and close to that of a Li2S/silicon cell. The high energy density and low cost of both Al and S makes Al/S system a very promising battery chemistry for large scale applications like electric vehicle and grid storage. Motivated by the potential, Cohn et al. recently demonstrated a proof-of-concept non-aqueous Al/S battery. Though demonstrating close to theoretical capacity with operating voltage of 1.2 V, the reported Al/S cell cannot be recharged, resulting in the loss of all capacity within three cycles. Up to now, there was no demonstration of reversible Al/S battery, probably due to the inability to recharge AlSx.In this work, we demonstrate a reversible Al/S cell with specific cathode capacity of ~1200 mAh/gs for over 20 cycles. Kinetics analysis point out the system is limited by slow diffusion of Al containing anion due to the high viscosity of the ionic liquid electrolyte. Raising temperature is proved to be an effective approach to mitigate the kinetic limitation thus decrease the hysteresis during charge and discharge. Spectroscopic and microscopic observations explore the mechanism of sulfur redox in the RTIL-AlCl3 electrolyte and enabled us to monitor the interfacial processes on both the cathode and anode. We believe that the new scientific insights obtained in this work will demonstrate inspiring progress on the way to realize a rechargeable Al/S battery.

A novel non-aqueous aluminum sulfur battery

An aluminum–sulfur battery comprised of a composite sulfur cathode, aluminum anode and an ionic liquid electrolyte of AlCl3/1-ethyl-3-methylimidazolium chloride is described. The electrochemical reduction of elemental sulfur has been studied in different molar ratios of the electrolyte, and aluminum tetrachloride ions have been identified at the electroactive ionic species. The Al/S battery exhibits a discharge voltage plateau of 1.1–1.2 V, with extremely high charge storage capacity of more than 1500 mAh g−1, relative to the mass of sulfur in the cathode. The energy density of the Al/S cell is estimated to be 1700 Wh kg−1 sulfur, which is competitive with the most attractive battery chemistries targeted for high-energy electrochemical storage. Characterization by means of SEM, XRD and XPS of the battery components reveal complete dissolution of sulfur-based discharge products to the electrolyte. The low cost, natural abundance and high volumetric energy density of both anode and cathode materials define a research path for new materials and cell designs for next-generation Al/S battery systems.

High Energy Non-Aqueous Al-S Battery

Advanced high energy storage systems, beyond Li-ion technology, are highly desired to meet the demands of high performance electronic devices and future electric vehicles. Aluminum is the third most abundant element and the most abundant metal in the earth’s crust. A rechargeable battery that utilizes an aluminum-based redox couple, which involves three electron transfers during electrochemical charge/discharge reactions, is desired and attractive for research. The low cost, suitable redox potential (E0 (Al3+/Al) =-1.676 Vs. NHE), and high charge density are all factors that have fueled this interest over the years. Sulfur has likewise received great attention as a cathode for Li-S and Na-S batteries because of its high charge-storage capacity, high natural abundance, low cost and environmental friendliness.In our study we present a new class of high energy system, a non-aqueous aluminum – sulfur battery. This battery is based on the coupling of Al metal anode and sulfur-carbon blend as the cathodic material. The system is employing electrolyte blend of AlCl3 and EMI∙Cl ionic liquid, where its composition controls its Lewis acidity. Our preliminary results show that the Al-S cell exhibits discharge voltage of around 1.2V, and a specific energy greater than 1700 Wh/kg, which exceeds most of today’s state-of-the-art batteries. Battery operation mechanism, product characteristics and limiting factors are studied using spectroscopic and electrochemical tool. This type of battery would be cheaper compare to current Li-ion and Li-S batteries, would be less prone to safety problems, and may lead to a major advance in the search for better batteries.

Nonaqueous Aluminum Nitride Extrusion: II, Die‐Land Flow and Tribology

Die‐land flow on extruding a nonaqueous aluminum nitride plastic body was analyzed using simultaneous orifice and capillary rheometry. Extrudate slip on the wall of the die‐land was observed and concluded to involve frictional slip of extrudate particles against the die‐wall and the viscous flow of an annular liquid. Results supported a model of a hydroplaning mechanism for the radial consolidation of the particle and binder network with complementary syneresis of liquid. The thickness of the apparent annular slip film was calculated to be submicrometer and to increase with an increase in the extrudate velocity and a decrease in the bulk yield stress and diameter of the die‐land. The flow stress on approaching the critical volume concentration of particles terminating plastic flow increased abruptly for shear of the body in the die‐entry but more gradually for slip in the die‐land. Shear resistance in the die‐land was significantly decreased on adding a lubricant and was very dependent on the contact stress between the particle network and the die‐wall, controlled by the degree of pore saturation for an unsaturated body and the volume of particles and binder for the saturated extrudate.

Fluorinated Graphites as Energetic Cathodes for Nonaqueous Al Batteries

Conventional cathodes utilized in nonaqueous lithium anode batteries, including manganese and vanadium oxides, and molybdenum or titanium sulfides, are incompatible with nonaqueous aluminum anode electrochemical storage processes. Alternative cathodes systems were explored to develop high charge capacity nonaqueous aluminum cells. A series of high storage capacity Al cells, utilizing cathodes composed of CF x fluorinated polymer graphite compounds are demonstrated. Significant CF x cathodic capacities are obtained in aluminum anode cells utilizing a 0.3 M tetraethylammonium chloride, 10 mM Hg(CH 3 COO) 2 acetonitrile electrolyte. The addition of hydroxide to the CF x cathode mixture increases discharge potential, while the addition of nonfluorinated 1 μm graphite increases measured cathodic capacity. The CF x cathode capacity increases with the degree of fluorination from 27 to 35% fluorine, is approximately constant from 35 to 58% fluorine, increases in capacity for 61% fluorine, and increases again with 63% fluorine (the highest available level of 63% fluorine available in the CF x ). Measured cathode capacities exceed 250 mAh g - 1 . For example, in excess of 300 mAh g - 1 , total cathode mass is measured for a 50:50 wt % cathode composite containing 55% fluorinated CF x and half 1 μm nonfluorinated graphite.