Aluminum-sulfur Batteries Research Articles

MOF-Derived Nitrogen-Rich Hollow Nanocages as a Sulfur Carrier for High-Voltage Aluminum Sulfur Batteries.

Aluminum-sulfur batteries (ASBs) are emerging as promising energy storage systems due to their safety, low cost, and high theoretical capacity. However, it remains a challenge to overcome voltage hysteresis and short cycle life in the sulfur/Al2S3 conversion reaction, which hinders the development of ASBs. Here, we studied a high-voltage ASB system based on sulfur oxidation in an AlCl3/urea electrolyte. Nitrogen-doped hollow nanocages (HNCs) synthesized from MOF precursors were rationally designed as sulfur/carbon composite electrodes (S@HNC), and the impact of the nitrogen species on the electrochemical performance of sulfur electrodes was systematically investigated. The S@HNC-900 achieved efficient conversion at 1.9 V, delivering a stable capacity of 197.3 mA h g-1 and a Coulombic efficiency of 93.28% after 100 cycles. Furthermore, the S@HNC-900 electrode exhibited exceptional rate capacity and 800th long-term cycling stability, retaining a capacity of 87.1 mA h g-1 at 500 mA g-1. Ex situ XPS and XRD characterizations elucidated the redox mechanism, revealing a four-electron transfer process (S/AlSCl7) at the S@HNC-900 electrode. Density functional theory calculations demonstrated that pyridinic nitrogen-enriched HNC-900 significantly enhanced the sulfur conversion reaction and facilitated the adsorption of sulfur intermediates (SCl3+) on the carbon interface. This work provides critical insights into the high-voltage sulfur redox mechanism and establishes a foundation for the rational design of carbon-based electrocatalysts for the enhancement of ASB performance.

Atomic-scale insights into the electrochemical mechanisms of aluminum-sulfur batteries: A first-principles study of Al-S clusters on graphene

Aluminum-sulfur (Al-S) batteries, known for their high energy density, cost-effectiveness, and sustainability, face challenges due to limited understanding of their atomic-level electrochemical mechanisms. This study uses first-principles calculations to explore the geometric and electronic structures of Al-S clusters and their interaction with graphene substrates. Key findings include charge transfer from graphene to Al-S clusters, especially in C@Al2S6 and C@Al2S3, and moderate adsorption strength crucial for reversible cycling. Thermodynamic analysis identifies the free energy change in the transition from C@Al2S6 to C@Al2S3, while AIMD simulations confirm structural stability, providing insights for optimizing Al-S battery performance.

Enabling long cycle aluminum-sulfur batteries via structurally stable Co, N-doped graphene-CNTs covalently bonded hybrid

Al-S batteries offer advantages such as high energy density, low cost, and good safety. However, they face challenges including poor sulfur conductivity, volume expansion, and slow kinetics of polysulfides, leading to rapid capacity decay and short cycle life. Therefore, the design of materials with high conductivity, capable of anchoring polysulfides, and structurally robust is crucial for enhancing the overall performance of Al-S batteries. To address these issues, we propose the construction of a structurally stable graphene-carbon nanotubes (CNTs) covalently bonded hybrid and a three-dimensional (3D) conductive framework catalyzed by Co active sites. The porous Co, N-doped graphene-carbon nanotubes (CoN-GC) hybrid with excellent mechanical properties provides sufficient space for high sulfur loading, alleviating sulfur volume expansion. Co plays a key role in rapidly transporting electrons, adsorbing, and catalyzing aluminum polysulfides. The Al-S battery using S@CoN-GC cycles over 1500 cycles at a current density of 300 mA·g−1, maintaining a specific capacity of 315 mAh·g−1, and retains 278 mAh·g−1 after 2000 cycles. Additionally, utilizing the outstanding mechanical properties of CoN-GC, a flexible Al-S microbattery was successfully fabricated, maintaining a capacity retention of 90 % after folding 1000 times. These research findings are expected to accelerate the study of multivalent metal-sulfur batteries and their practical applications in various scenarios.

Polyoxomolybdate-Based Metal-Organic Framework-Derived Cu-Embedded Molybdenum Dioxide Hybrid Nanoparticles as Highly Efficient Electrocatalysts for Al-S Batteries.

High-performance rechargeable aluminum-sulfur batteries (RASB) have great potential for various applications owing to their high theoretical capacity, abundant sulfur resources, and good safety. Nevertheless, the practical application of RASB still faces several challenges, including the polysulfide shuttle phenomenon and low sulfur utilization efficiency. Here, we first developed a synergistic copper heterogeneous metal oxide MoO2 derived from polymolybdate-based metal-organic framework as an efficient catalyst for mitigating polysulfide diffusion. This composite enhances sulfur utilization and electrical conductivity of the cathode. DFT calculations and experimental results reveal the catalyst Cu/MoO2@C not only effectively anchors aluminum polysulfides (AlPSs) to mitigate the shuttle effect, but also significantly promotes the catalytic conversion of AlPSs on the sulfur cathode side during charging and discharging. The unique nanostructure contains abundant electrocatalytic active sites of oxide nanoparticles and Cu clusters, resulting in excellent electrochemical performance. Consequently, the established RASB exhibits an initial capacity of 875 mAh g-1 at 500 mA g-1 and maintains a capacity of 967 mAh g-1 even at a high temperature of 50 °C.

Interfacial redox modulation of polysulfides with ferrocene functionalized separator in Al–S batteries

Despite the bright future of aluminum-sulfur (Al–S) batteries due to the ultrahigh energy-to-price ratios, the development of this new energy storage system is plagued by the shutting of polysulfides and sluggish kinetics during redox conversions. Herein, ferrocene as efficient polysulfide mediators and electrocatalysts is covalently grafted onto glass fiber (GF) membranes, which serves as separators in Al–S batteries. Attributed to the strong chemisorption and catalytic effect of metallocene toward polysulfide conversions, Al–S cells assembled with the grafted separators deliver an ultrahigh initial capacity of 1347.9 mAh g−1 (at 200 mA g−1) and desirable rate performance (328.1 mAh g−1 at 500 mA g−1). As validated by theoretical calculations, effective polysulfide binding is achieved through beneficial cation-π interactions between Al3+ in polysulfides and the negatively charged cyclopentadienyl ligands in ferrocene, providing novel insights into the exploration of metal-sulfur chemistries for stable energy storage.

Locally Concentrated Ionic Liquid Electrolytes for Wide-Temperature-Range Aluminum-Sulfur Batteries.

Aluminum-sulfur (Al-S) batteries are promising energy storage devices due to their high theoretical capacity, low cost, and high safety. However, the high viscosity and inferior ion transport of conventionally used ionic liquid electrolytes (ILEs) limit the kinetics of Al-S batteries, especially at sub-zero temperatures. Herein, locally concentrated ionic liquid electrolytes (LCILE) formed via diluting the ILEs with non-solvating 1,2-difluorobenzene (dFBn) co-solvent are proposed for wide-temperature-range Al-S batteries. The addition of dFBn effectively promotes the fluidity and ionic conductivity without affecting the AlCl4 - /Al2 Cl7 - equilibrium, which preserves the reversible stripping/plating of aluminum and further promotes the overall kinetics of Al-S batteries. As a result, Al-S cells employing the LCILE exhibit higher specific capacity, better cyclability, and lower polarization with respect to the neat ILE in a wide temperature range from -20 to 40 °C. For instance, Al-S batteries employing the LCILE sustain a remarkable capacity of 507 mAh g-1 after 300 cycles at 20 °C, while only 229 mAh g-1 is delivered with the dFBn-free electrolyte under the same condition. This work demonstrates the favorable use of LCILEs for wide-temperature Al-S batteries.

Locally Concentrated Ionic Liquid Electrolytes for Wide‐Temperature‐Range Aluminum‐Sulfur Batteries

AbstractAluminum−sulfur (Al−S) batteries are promising energy storage devices due to their high theoretical capacity, low cost, and high safety. However, the high viscosity and inferior ion transport of conventionally used ionic liquid electrolytes (ILEs) limit the kinetics of Al−S batteries, especially at sub‐zero temperatures. Herein, locally concentrated ionic liquid electrolytes (LCILE) formed via diluting the ILEs with non‐solvating 1,2‐difluorobenzene (dFBn) co‐solvent are proposed for wide‐temperature‐range Al−S batteries. The addition of dFBn effectively promotes the fluidity and ionic conductivity without affecting the AlCl4−/Al2Cl7− equilibrium, which preserves the reversible stripping/plating of aluminum and further promotes the overall kinetics of Al−S batteries. As a result, Al−S cells employing the LCILE exhibit higher specific capacity, better cyclability, and lower polarization with respect to the neat ILE in a wide temperature range from −20 to 40 °C. For instance, Al−S batteries employing the LCILE sustain a remarkable capacity of 507 mAh g−1 after 300 cycles at 20 °C, while only 229 mAh g−1 is delivered with the dFBn‐free electrolyte under the same condition. This work demonstrates the favorable use of LCILEs for wide‐temperature Al−S batteries.

Rapid-charging aluminium-sulfur batteries operated at 85 °C with a quaternary molten salt electrolyte

Molten salt aluminum-sulfur batteries are based exclusively on resourcefully sustainable materials, and are promising for large-scale energy storage owed to their high-rate capability and moderate energy density; but the operating temperature is still high, prohibiting their applications. Here we report a rapid-charging aluminium-sulfur battery operated at a sub-water-boiling temperature of 85 °C with a tamed quaternary molten salt electrolyte. The quaternary alkali chloroaluminate melt – possessing abundant electrochemically active high-order Al-Cl clusters and yet exhibiting a low melting point – facilitates fast Al3+ desolvation. A nitrogen-functionalized porous carbon further mediates the sulfur reaction, enabling the battery with rapid-charging capability and excellent cycling stability with 85.4% capacity retention over 1400 cycles at a charging rate of 1 C. Importantly, we demonstrate that the asymmetric sulfur reaction mechanism that involves formation of polysulfide intermediates, as revealed by operando X-ray absorption spectroscopy, accounts for the high reaction kinetics at such temperature wherein the thermal management can be greatly simplified by using water as the heating media.

Modified Solid Electrolyte Interphases with Alkali Chloride Additives for Aluminum-Sulfur Batteries with Enhanced Cyclability

Al-S batteries are promising energy storage devices, employing high-capacity and low-cost Al (2980 mA h g-1, 8050 mAh cm-3) and sulfur (1672 mAh g-1) as the anode and cathode, respectively. However, Al-S batteries suffer from the notorious shuttle effect of polysulfides as other intensively investigated metal-sulfur batteries. Up to now, several strategies have been proposed to improve the poor reversibility and lifespan of Al-S batteries. At the cathode side, materials that can adsorb polysulfides have been employed as the host material of sulfur to reduce the dissolution of polysulfides,1,2 e.g., heteroatom-functionalized and/or hierarchical porous carbonaceous materials, metal-organic frameworks (MOFs), boron nitrides, and Mxenes.3,4 Nonetheless, AMAs, which also play an important role in the shuttle process, have received little attention up to now. Suitable engineering of electrolytes enabling an electronically insulating solid electrolyte interphase (SEI) on AMAs may suppress the deposition of low-solubility Al2S3 and/or short-chain polysulfides further promoting the cell cycling performance.Herein, alkali chlorides are, for the first time, proposed as electrolyte additives to modify the SEI on AMAs and suppress the polysulfide shuttle in Al-S batteries.5 It is demonstrated that adding NaCl to the conventional [AlCl3]1.3[EmimCl]1 electrolyte can enhance the cyclability of Al-S batteries by forming a thicker, NaxAlyO2-containing SEI layer on AMAs. In addition to NaCl, LiCl and KCl as electrolyte additives also lead to improvement of Al-S batteries’ lifespan. These findings provide a new path to suppress the detrimental polysulfides shuttle effect in Al-S batteries, resulting in their improved cycle performance. References (1) Smajic, J.; Wee, S.; Simoes, F. R. F.; Hedhili, M. N.; Wehbe, N.; Abou-Hamad, E.; Costa, P. M. F. J. Capacity Retention Analysis in Aluminum-Sulfur Batteries. ACS Appl. Energy Mater. 2020, 3 (7), 6805–6814.(2) Zhang, Y.; Ma, L.; Tang, R.; Zheng, X.; Wang, X.; Dong, Y.; Kong, G.; Zhao, F.; Wei, L. The Host Hollow Carbon Nanospheres as Cathode Material for Nonaqueous Room-Temperature Al–S Batteries. Int. J. Hydrogen Energy 2021, 46 (7), 4936–4946.(3) Guo, Y.; Jin, H.; Qi, Z.; Hu, Z.; Ji, H.; Wan, L. J. Carbonized-MOF as a Sulfur Host for Aluminum–Sulfur Batteries with Enhanced Capacity and Cycling Life. Adv. Funct. Mater. 2019, 29 (7), 1–6.(4) Wang, Z.; Zheng, X.; Chen, A.; Han, Y.; Wei, L.; Li, J. Unraveling the Anchoring Effect of MXene-Supported Single Atoms as Cathodes for Aluminum−Sulfur Batteries. ACS Mater. Lett. 2022, 4, 8, 1436-1445.(5) Xu, C.; Diemant, T.; Liu, X.; Passerini, S. Modified Solid Electrolyte Interphases with Alkali Chloride Additives for Aluminum–Sulfur Batteries with Enhanced Cyclability. Adv. Funct. Mater. 2023. 2214405.

Three-Dimensional Nitrogen-Doped Carbonaceous Networks Anchored with Cobalt as Separator Modification Layers for Low-Polarization and Long-Lifespan Aluminum-Sulfur Batteries.

Aluminum-sulfur (Al-S) batteries have attracted extensive interest due to their high theoretical energy density, inherent safety, and low cost. However, severe polarization and poor cycling performance significantly limit the development of Al-S batteries. Herein, three-dimensional (3D) nitrogen-doped carbonaceous networks anchored with cobalt (Co@CMel-ZIF) is proposed as a separator modification layer to mitigate these issues, prepared via carbonizations of a mixture of ZIF-7, melamine, and CoCl2. It exhibits a 3D network structure with a moderate surface area and high average pore diameter, which is demonstrated to be effective in adsorbing the aluminum polysulfides and hindering the mobility of polysulfides across the separator for enhanced cyclic stability of Al-S batteries. Meanwhile, Co@CMel-ZIF are characterized by abundant catalytic pyridinic-N and Co-Nx active sites that effectively eliminate the barrier of sulfides' conversion and thereby facilitate the polarization reduction. As a result, Al-S cells based on the separator modified with Co@CMel-ZIF exhibit a low voltage polarization of 0.47 V under the current density of 50 mA g-1 at 20 °C and a high discharge specific capacity of 503 mAh g-1 after 150 cycles. In contrast, the cell employing a bare separator exhibits a polarization of 1.01 V and a discharge capacity of 300 mAh g-1 after 70 cycles under the same conditions. This work demonstrates that modifying the separators is a promising strategy to mitigate the high polarization and poor cyclability of Al-S batteries.

Fluorinated Benzimidazole-Linked Highly Conjugated Polymer Enabling Covalent Polysulfide Anchoring for Stable Sulfur Batteries.

Sulfur is one of the most abundant and economical elements in the p-block family and highly redox active, potentially utilizable as a charge-storing electrode with high theoretical capacities. However, its inherent good solubility in many electrolytes inhibits its accessibility as an electrode material in typical metal-sulfur batteries. In this work, the synthetically designed fluorinated porous polymer, when treated with elemental sulfur through a well-known nucleophilic aromatic substitution mechanism (SN Ar), allows for the covalent integration of polysulfides into a highly conjugated benzimidazole polymer by replacing the fluorine atoms. Chemically robust benzimidazole linkages allow such harsh post-synthetic treatment and facilitate the electronic activation of the anchored polysulfides for redox reactions under applied potential. The electrode amalgamated with sulfurized polymer mitigates the so-called polysulfide shuttle effect in the lithium-sulfur (Li-S) battery and also enables a reversible, more environmentally friendly, and more economical aluminum-sulfur (Al-S) battery that is configured with mostly p-block elements as cathode, anode, and electrolytes. The improved cycling stabilities and reduction of the overpotential in both cases pave the way for future sustainable energy storage solutions.

Recent Theoretical and Experimental Advancements of Aluminum-Sulfur Batteries.

Aluminum-sulfur batteries (AlSBs) exhibit significant potential as energy storage systems due to their notable attributes, including a high energy density, cost-effectiveness, and abundant availability of aluminum and sulfur. In order to commercialize AlSBs, an understanding of their working principles is necessary. In this review, we examine the current advancements in cathodes, both in theory and practice, as well as the progress made in aqueous and nonaqueous electrolytes. We also explore the modifications made to separators and the theoretical understanding of problems associated with AlSBs. Furthermore, we discuss future research directions aimed at resolving these issues. Our aim is to summarize the current progress in AlSBs and, based on recent progress and understanding of the mechanism, help design a battery to overcome the challenges that such batteries have been facing.

Strategies for Realizing Rechargeable High Volumetric Energy Density Conversion‐Based Aluminum–Sulfur Batteries

AbstractAluminum–sulfur batteries (ASBs) are deemed to be alternatives to meet the increasing demands for energy storage due to their high theoretical capacity, high safety, low cost, and the rich abundances of Al and S. However, the challenging problems including sluggish conversion kinetics, inferior electrolyte compatibility, and potential dendrite formation are still remained. This review comprehensively focuses on summarizing the specific strategies from polysulfide shuttling inhibition to form smooth anodic Al activation/deposition. Especially, innovations in cathodic side for achieving electrochemical kinetic modulations, electrolyte optimizations, and anodic interface mediations are discussed. Upon detailed elaborating the formation process, influencing factors, and their interactions in the Al–S electrochemistry, a comprehensive summary of their causative mechanisms and the corresponding strategies are provided, including optimization of electrolytes, innovative in situ detections, and precise electrocatalytic strategies. Based on such a systematic understanding in the Al–S electrochemistry, the possible electrochemical reaction mechanism is deciphered more clearly and enlightened practical strategies on the future development of stable ASBs. Furthermore, future opportunities and directions of high‐performance conversion‐based Al–S batteries for large‐scale energy storage applications are highlighted.

Single-atom electrocatalyst and gel polymer electrolyte boost the energy density and life of aluminum-sulfur batteries

Aluminum-sulfur (Al-S) batteries are regarded as a desirable candidate for large-scale energy storage because of their high energy density and abundant natural resources of electrode materials. To address the critical issues of low discharge voltage and rapid capacity decay in Al-S batteries, here an electrocatalyst-assisted gel-polymer electrolyte (GPE)-based Al-S battery is fabricated using platinum nanoparticles decorated platinum/nitrogen co-doped graphene (PtNG) as sulfur host for positive electrode and metal-organic frameworks (MOF) filled GPE (MOF@GPE) as solid electrolyte. Pt-based active sites derived from Pt nanoclusters’ surface and atomically dispersed Pt-N2 chemical bonds in PtNG can catalyze the decomposition of sulfur and polysulfides in the electrochemical process, greatly accelerating the sulfur redox kinetics. Furthermore, the MOF fillers in MOF@GPE electrolyte significantly inhibit the shuttle effect of polysulfides, efficiently improving the utilization of sulfur. Consequently, the established Al-S battery delivers a specific capacity of 1009 mAh g−1 with a discharge plateau of ∼0.95 V, along with a capacity retention of 65% after 300 cycles, revealing ultrahigh energy density and long cycle life. Such a strategy of combining electrocatalyst and MOF-based gel electrolyte affords a fresh plateau for promoting the rechargeable ability of Al-S batteries, advancing remarkable routes for achieving efficient and stable energy storage devices.

Modified Solid Electrolyte Interphases with Alkali Chloride Additives for Aluminum–Sulfur Batteries with Enhanced Cyclability

AbstractAluminum–sulfur batteries employing high‐capacity and low‐cost electrode materials, as well as non‐flammable electrolytes, are promising energy storage devices. However, the fast capacity fading due to the shuttle effect of polysulfides limits their further application. Herein, alkaline chlorides, for example, LiCl, NaCl, and KCl are proposed as electrolyte additives for promoting the cyclability of aluminum–sulfur batteries. Using NaCl as a model additive, it is demonstrated that its addition leads to the formation of a thicker, NaxAlyO2‐containing solid electrolyte interphase on the aluminum metal anode (AMA) reducing the deposition of polysulfides. As a result, a specific discharge capacity of 473 mAh g−1 is delivered in an aluminum–sulfur battery with NaCl‐containing electrolyte after 50 dis‐/charge cycles at 100 mA g−1. In contrast, the additive‐free electrolyte only leads to a specific capacity of 313 mAh g−1 after 50 cycles under the same conditions. A similar result is also observed with LiCl and KCl additives. When a KCl‐containing electrolyte is employed, the capacity increases to 496 mA h g−1 can be achieved after 100 cycles at 50 mA g−1. The proposed additive strategy and the insight into the solid electrolyte interphase are beneficial for the further development of long‐life aluminum–sulfur batteries.

Advances of Electroactive Metal-Organic Frameworks.

The preparation of electroactive metal-organic frameworks (MOFs) for applications of supercapacitors and batteries has received much attention and remarkable progress during the past few years. MOF-based materials including pristine MOFs, hybrid MOFs or MOF composites, and MOF derivatives are well designed by a combination of organic linkers (e.g., carboxylic acids, conjugated aromatic phenols/thiols, conjugated aromatic amines, and N-heterocyclic donors) and metal salts to construct predictable structures with appropriate properties. This review will focus on construction strategies of pristine MOFs and hybrid MOFs as anodes, cathodes, separators, and electrolytes in supercapacitors and batteries. Descriptions and discussions follow categories of electrochemical double-layer capacitors (EDLCs), pseudocapacitors (PSCs), and hybrid supercapacitors (HSCs) for supercapacitors. In contrast, Li-ion batteries (LIBs), Lithium-sulfur batteries (LSBs), Lithium-oxygen batteries (LOBs), Sodium-ion batteries (SIBs), Sodium-sulfur batteries (SSBs), Zinc-ion batteries (ZIBs), Zinc-air batteries (ZABs), Aluminum-sulfur batteries (ASBs), and others (e.g., LiSe, NiZn, H+ , alkaline, organic, and redox flow batteries) are categorized for batteries.

Electroactive-catalytic conductive framework for aluminum-sulfur batteries

Rechargeable aluminum‒sulfur batteries (RASBs), despite the great advantage of high energy density and low cost, are suffering from insulative solid sulfur species and sluggish reaction kinetics. The routine solution of introducing an excessive amount of inactive carbon will cause the low active material's proportion and thus high electrode porosity, dramatically compromising the energy densities. More importantly, the high Gibbs free energy of the Al 2 S 3 decomposition remains unsolved. Herein, an Al 3+ -intercalative and catalytic electronic conductive framework (ECF) is constructed by Mo 6 S 8 to replace conventional inactive carbon, in which Mo 6 S 8 will build an efficient conductive network, provide high Al-ion storage capability, have a strong affinity to polysulfides to restrain their dissolution, and show superior catalytic activity on the decomposition of Al 2 S 3 . Consequently, the Mo 6 S 8 /S cathode achieves a highly competitive specific energy of 371 Wh/kg cathode (ca) , with the voltage hysteresis of sulfur redox markedly decreased by 569 mV. Our Al 3+ -intercalative and catalytic ECF notably enhances the specific energy and energy efficiency of RASBs, which will push multivalent metal-sulfur batteries forward to practical application. An Al 3+ -intercalative and catalytic electronic conductive framework is constructed by Mo 6 S 8 to replace conventional inactive carbon in the sulfur cathode, in which Mo 6 S 8 will build an efficient conductive network, provide high Al-ion storage capability, have a strong affinity to polysulfides to restrain their dissolution, and show superior catalytic activity on the decomposition of Al 2 S 3 .

An aluminum–sulfur battery may become an inexpensive alternative to lithium-ion cells

An aluminum–sulfur battery may become an inexpensive alternative to lithium-ion cells

Atomically Dispersed Iron Active Sites Promoting Reversible Redox Kinetics and Suppressing Shuttle Effect in Aluminum–Sulfur Batteries

HighlightsFe single atoms supported on porous carbon nanofiber are prepared by spatial confinement.The iron single atoms supported on porous nitrogen-doped carbon nanofibers (FeSAs-NCF) can promote the reversible conversion between aluminum polysulfides.The FeSAs-NCF can chemically anchor the polysulfides to suppress shuttle effect.

Unraveling the Anchoring Effect of MXene-Supported Single Atoms as Cathodes for Aluminum–Sulfur Batteries

Unraveling the Anchoring Effect of MXene-Supported Single Atoms as Cathodes for Aluminum–Sulfur Batteries