Anode Interface Research Articles

Polylatic Acid Nanofiber-Guided Uniform Lithium Deposition for Stable Lithium Metal Anodes

Lithium (Li) metal has been considered as potential choices for high-energy density batteries. However, the uncontrollable growth of Li dendrites and the infinite relative volume changes of Li anodes hinder its practical application. Herein we demonstrate a strategy to protect the Li metal anode by using a polylatic acid (PLA) nanofiber film. This polymer nanofiber film exhibits high ionic conductivity, flexibility, and chemical affinity, which enable the fast transfer of Li-ion and the feasibility to accommodate the volume changes of Li metal, and further resulting in a dendrite-free anode and stable interface. Numerous polar groups on the surface of PLA nanofibers can guide the orderly migration of Li ions. Besides, PLA nanofiber can form an artificial solid electrolyte interphase (SEI) layer by in situ reaction. Based on these advantages, we realize a high average coulombic efficiency (CE) of 95% within 150 cycles in a Li|Cu cell. When the LiCoO2 cathode was assembled with PLA-protected Li anode, a high capacity retention (81%) within 100 cycles at 89mAg−1(1 C = 178mAhg−1) is obtained. This work highlights the advantages of an in situ polymer nanofiber artificial SEI layer in stabilizing Li metal anode and provides a fresh insight for the design of artificial SEI layer.

Integrated electrolyte regulation strategy: Trace trifunctional tranexamic acid additive for highly reversible Zn metal anode and stable aqueous zinc ion battery

Aqueous zinc ion batteries (AZIBs) are appealing increasing attention for large-scale energy storage systems (ESS) due to their intrinsic safety, low cost, and scalability. Unfortunately, the Zn metal anode suffers from chaotic side reactions, rampant dendrite growth and continuous hydrogen evolution, severely hampering the application of AZIBs. Herein, the trifunctional tranexamic acid (TXA) is introduced into aqueous electrolyte to form unique anode/electrolyte interface, enhance steric effect and regulate Zn2+ solvation structure. Theoretical calculations first illustrate the mechanism of TXA additive on Zn metal anode and electrolyte. Experimental results and molecular dynamic simulations further demonstrate the vital role of TXA in simultaneously regulating the anode interface chemistry and electrolyte environment. Consequently, Zn//Zn symmetric cells deliver a durable lifespan of over 2000 h at 1 mA cm–2, and a high cumulative capacity at 5 mA cm–2. A highly reversible Zn plating/stripping processes for over 1000 cycles in Zn//Cu asymmetric cells are also achieved. Moreover, the assembled Zn//NiCo-MnO2 and Zn//NH4V4O10 full cells exhibit stable cycling performance and high capacity retentions. This work proposes a novel and facile integrated electrolyte regulation strategy to realize dendrite-free Zn anodes and stable full cells, which is favorable for advanced AZIBs and beyond.

Towards understanding uniformity of megasonic-assisted through-mask electrochemical micromachining based on bubble dynamics

In through-mask electrochemical micromachining (TMEMM), bubbles on the anode surface can lead to ohmic voltage drop and non-uniform conductivity distribution, resulting in lower etching accuracy. With the advantages of low cavitation effect, strong acoustic streaming and high acoustic intensity, megasonic facilitates the reduction of bubble accumulation on the anode surface, thus improving etching accuracy. In this paper, a multiphysics field simulation model is developed to predict the two-phase flow evolution and etching profile at the anode interface. The simulation results show that the gas content at the anode interface in the megasonic field is low, and the gas distribution is relatively uniform. The etching depth and etching uniformity of TMEMM are improved. Experiments demonstrate the accuracy of the proposed simulation model. In addition, micro pits array with CVdiameter and CVdepth of 2.28 % and 5.70 %, respectively, were prepared using the MA-TMEMM method. Visualization experiments systematically study the machining mechanism of MA-TMEMM. The underlying dynamic force balance on the gas bubble is analyzed to illustrate the mechanism and experimental observations. Finally, the advantage of megasonic in removing bubbles from the anode surface to improve etching uniformity was demonstrated by counting the detached bubble diameter and effective coverage.

Bimetal-organic framework-derived porous CoFe2O4 nanoparticles as biocompatible anode electrocatalysts for improving the power generation of microbial fuel cells

HypothesisThe relatively lower power density of Microbial fuel cells (MFCs), primarily resulting from weak biofilm habitation and sluggish extracellular electron transfer (EET) at the anode interface, limits their practical implementation on a large scale. To address this challenge, porous CoFe2O4 nanoparticles could be used as anode electrocatalysts based on the following considerations: (i) the introduction of CoFe2O4 nanoparticles endows the anode with a rough surface that facilitates biofilm formation; (ii) the positively charged Co and Fe ions improve the interfacial affinity of anodes, enabling rapid immobilization and colonization of negatively bacteria; (iii) the multi-valent metal states of Co and Fe can function as electron shuttles, mediating EET process between biofilm and anode. ExperimentsCoFe2O4 nanoparticles prepared with a bimetal-organic framework (B-MOF) as precursor, were modified to the surface of carbon cloth as the anode of MFCs. FindingsMFCs equipped with CoFe2O4 anode achieved a maximum power density of 1026.68 mW m−2, which was approximately 3.4 times higher than that of the pristine carbon cloth. Additionally, the biofilm density and viability on the anode were enhanced after CoFe2O4 modification. Considering the facile fabrication process and superior electrocatalytic performance, the CoFe2O4 nanoparticles are promising electrocatalysts for high performance and cost-effective MFCs.

Self‐Formed Fluorinated Interphase with Fe Valence Gradient for Dendrite‐Free Solid‐State Sodium‐Metal Batteries

AbstractThe poor anode/electrolyte compatibility and dendrite growth have discouraged the development of solid‐state sodium‐metal batteries (SSSMBs). Here, a self‐formed interphase with a unique Fe valence gradient is designed to stabilize the anode interface of Na3Zr2Si2PO12 solid electrolyte. This interphase consists of a Fe‐ and NaF‐containing outer layer near the Na anode and a Fe2+/Fe3+‐rich inner layer, which are in situ formed upon contacting Na with a sodiophilic α‐Fe2O3‐xFx interlayer specially coated on Na3Zr2Si2PO12. The NaF and Fe prevents continuous reduction reactions and homogenize the electric filed, while the iron oxide gradient layer offers buffering Na storage during plating, further suppressing dendrite growth. Benefiting from the dynamically stable, low‐impedance and dendrite‐free interface, the symmetric cells achieve a 20‐fold reduction in interfacial resistance and a fourfold enhancement in critical current density (CCD) at 25 °C, and powered a high CCD of 1.9 mA cm‐2 and a 1000‐h cycle life at 1 mA cm‐2 at 80 °C. The corresponding SSSMBs based on Na3V2(PO4)3 cathodes deliver a capacity retention rate of 96% over 120 cycles at 1 C. This robust interface design supports one of the best electrochemical performances ever reported and offers a comprehensive solution to stabilize the Na3Zr2Si2PO12/Na interface toward practical SSSMBs.

Electromigration-induced remarkable intermetallic compound (IMC) formation in micro joints and its prevention

The electromigration reliability of Au/Pd(P)/Ni(P) surface finish in micro joints was investigated in this study. We found that the reaction of Pd(P) with molten Sn would yield a noticeable amount of (Pd,Ni)Sn4 intermetallic compound (IMC) scattering in the Sn matrix after soldering reaction. Interestingly, upon electron current stressing, (Pd,Ni)Sn4 was gradually driven to the anode interface, and a remarkable volume expansion was caused by the transition from a low Ni-containing (Pd0.22Ni0.78)Sn4 (17 μm on thickness) into a high Ni-containing (Pd0.04Ni0.96)Sn4 (56 μm on thickness) because of the substitution of Pd sublattice by a high fraction of Ni as a result of electromigration. This electromigration-induced unusual stoichiometric transition and massive IMC propagation has been rarely reported previously in the literature. The underlying mechanism associated with the electromigration phenomenon and mitigation strategies to the NiSn4 formation were proposed in this study.

Advances in Strategic Inhibition of Polysulfide Shuttle in Room-Temperature Sodium-Sulfur Batteries via Electrode and Interface Engineering

Room-temperature sodium-sulfur batteries (RT-NaSBs) with high theoretical energy density and low cost are ideal candidates for next-generation stationary and large-scale energy storage. However, the dissolution of sodium polysulfide (NaPS) intermediates and their migration to the anode side give rise to the shuttle phenomenon that impedes the reaction kinetics leading to rapid capacity decay, poor coulombic efficiency, and severe loss of active material. Inhibiting the generation of long-chain NaPS or facilitating their adsorption via physical and chemical polysulfide trapping mechanisms is vital to enhancing the electrochemical performance of RT-NaSBs. This review provides a brief account of the polysulfide inhibition strategies employed in RT-NaSBs via physical and chemical adsorption processes via the electrode and interfacial engineering. Specifically, the sulfur immobilization and polysulfide trapping achieved by electrode engineering strategies and the interfacial engineering of the separator, functional interlayer, and electrolytes are discussed in detail in light of recent advances in RT-NaSBs. Additionally, the benefits of engineering the highly reactive Na anode interface in improving the stability of RT-NaSBs are also elucidated. Lastly, the future perspectives on designing high-performance RT-NaSBs for practical applications are briefly outlined.

Rechargeable Sodium Solid‐State Battery Enabled by In Situ Formed Na–K Interphase

AbstractSolid‐state metal batteries have displayed great advantages in the domain of electrochemical energy storage owing to their remarkably improved energy density and safety. However, the practical application of solid‐state batteries (SSBs) is still greatly impeded by unfavorable interface stability and terrible low temperature performance. In this work, a local targeting anchor strategy is developed to realize an impressively long cycling life for a NASICON‐based solid‐state sodium metal battery at 0 °C. With the electrochemical migration of K+ from the cathode side to the anode side, a spontaneous generated liquid Na–K interphase can stabilize the ceramic electrolyte/metallic Na anode interface, and address the issues of sluggish kinetics at the interface together with metal dendrite deposition. In addition, the capability of K+ conduction in NASICON is also theoretically and experimentally validated. Of particular note, a K2MnFe(CN)6 cathode paired with a Na3Zr2Si2PO12 ceramic electrolyte and metallic Na anode, enable the long‐term cycling and excellent rate capability of all‐solid‐state sodium batteries at 0 °C. Without the purposely designed matrix host for a liquid Na–K interphase, this work opens up a new route for the design of high energy density SSBs.

Precisely adjusting the organic/electrode interface charge barrier for efficient and stable Ag-based regular perovskite solar cells with >23% efficiency

The hole transport layer (HTL)/anode interface plays an important role in high-performance regular Ag-based perovskite solar cells (PSCs). Usually, the charge barrier caused by the energy level mismatch at the HTL/Ag interface will lead to the abnormal s-type J-V curve, which seriously hindering the commercial application of Ag-based PSCs. Here, we introduce a solution processed molybdenum oxide (HxMoO3) into the HTL/Ag interface to form a double-hole HTL. The work function (WF) of HxMoO3 films can be adjusted by controlling the reaction time. The introduction of HxMoO3 can effectively change the energy-level bending orientation, promote the charge transport and suppresses carrier recombination, thus eliminate the s-type J-V curve. Finally, the Ag-based PSCs achieve a power conversion efficiency (PCE) of 23.16%. Meanwhile, the PCE of the four-terminal (4T) perovskite/silicon tandem cell reaches 26.76%. Furthermore, the HxMoO3 can also be used as a protective layer to prevent the erosion of moisture on the PSCs and the penetration of the silver electrode, improving the stability of the devices. This provides an important reference for the development of perovskites and their tandem solar cells.

A novel promotion strategy for microstructure and electrical performance of garnet electrolytes via Li4GeO4 additive

Cubic Li6.4La3Zr1.4Ta0.6O12 (c-LLZTO) electrolyte is one of the most promising solid electrolytes. However, it is rather difficult to promote its electrical performance while reducing process parameters. Therefore, Li4GeO4 is applied as the additive in liquid sintering of LLZTO ceramics in this study. The LLZTO@Li4GeO4/Li2O composite electrolyte sintered at 1180 °C for 3 h performs a significantly promoted microstructure and electrical performance, the ionic conductivity of which reaches 5.77 × 10−4 S cm−1 at 25 °C. The Li4GeO4/Li2O eutectic phase contributed prominently, in which the high concentration of Li+ seaming the LLZTO grains tightly. Meanwhile, Li+ conduction in the consecutive conductive pathways constructed by [GeO4] groups among the grains was greatly stimulated. With the modification of the grain boundary, an improved garnet electrolytes/Li anode interface performance is produced. The Li/Au|LLZTO@Li4GeO4/Li2O|Au/Li symmetrical cell is able to cycle stably for more than 500 h at the current density of 0.1 mA cm−2 at room temperature.

Mitigating the Efficiency Loss of Organic Photovoltaic Cells Using Phosphomolybdic Acid‐Doped PEDOT:PSS as Hole Transporting Layer

A phosphomolybdic acid (PMA)‐doped poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hole transporting layer (HTL) is developed to effectively optimize the anode interface of inverted organic photovoltaic (OPV) devices. Since a deep‐lying work function of HTL is in favor of reducing the interfacial barrier for hole transporting, superior power conversion efficiencies (PCE) of 9.22% and 10.8% are achieved in fullerene‐based and nonfullerene‐based devices in inverted architecture. Thus‐prepared OPV devices also exhibit excellent photostability and retain 85% of the initial PCE after 1000 h of irradiation under 100 mW cm−2 irradiation. The overall result suggests the practicability and mitigation of efficiency loss when replacing the conventional PEDOT:PSS with PMA‐doped PEDOT:PSS as HTL to fabricate highly efficient, inverted OPV devices.

The effect of defects for the ion transport of Li3ScCl6 and Li3InCl6 with the interface of lithium metal anode: A first-principles study

Li3ScCl6 and Li3InCl6 have good ionic conductivity and a wide stable chemical window, which showing great potential in many inorganic solid-state electrolytes. Due to the disordered occupancy phenomenon of the lattice sites between the framework lithium ions and the transported ions. The concentration nonuniformity of lithium ions causes the blocking of mobile ions in the transition metal lithium halide solid electrolyte. However, vacancy defects can cause changes in the charge balance of nonstoichiometric systems, which reducing blocking effects during ion diffusion. In addition, lithium dendrites still exist at the interface between the inorganic solid electrolyte and the lithium metal anode. It can effectively improve the occurrence of interface side reaction because LiF has high interface energy. The effect of vacancy defects for lithium ion migration parameters of Li3ScCl6 and Li3InCl6 at different temperatures are simulated by the first principle. The results showing that lithium ions had better migration and diffusion ability in the structure containing lithium site defects of Li3InCl6. A dual-halide electrolyte interface model was constructed to suppress the growth of Li dendrites on the surface of a Li metal anode. The Li3ScCl6-LiF heterostructure interface can stably control ion transport on the surface of a lithium metal anode.

Versatility of Sb-doping enabling argyrodite electrolyte with superior moisture stability and Li metal compatibility towards practical all-solid-state Li metal batteries

Sulfide solid-state electrolytes (SSEs) are considered as one of the most promising candidates for all-solid-state Li metal batteries (ASSLMBs) on account of their high ionic conductivity and outstanding ductility. However, the poor air stability and incompatibility with Li metal seriously obstruct their application in ASSLMBs. Herein, versatile Sb-doped Li6P1−xSbxS5Cl SSEs are successfully developed to tackle these issues. The synthesized Li6P0.925Sb0.075S5Cl displays an ultrahigh ionic conductivity of 3.6 × 10−3 S cm−1 at room temperature by optimizing the concentrations of dopant. Furthermore, such electrolyte exhibits remarkable structural stability and admirable hydrolysis resistance when exposed to humid air or water, owing to the formation of SbS4 units that are thermodynamically stable to water in the Sb-doped electrolyte. Importantly, the Li6P0.925Sb0.075S5Cl SSE can induce the formation of Li-Sb alloy at the Li/SSE interface, which serves critical functions to regulate the Li+ plating/stripping behavior and decrease Li+ diffusion energy barrier across the anode interface, thus endowing an excellent long-term cyclic stability of the Li symmetric batteries (stable cycle at 0.1 mA cm−2 over 800 h) and significantly improved critical current density (1.2 mA cm−2). More encouragingly, either pristine-synthesized or air-exposed Li6P0.925Sb0.075S5Cl enables ASSLMBs with satisfying electrochemical performance at room temperature.

Reconstructing the Anode Interface and Solvation Shell for Reversible Zinc Anodes.

The attractive advantages of the Zn metal anode and water-based electrolyte, such as inherent safety and low cost, endow the zinc-ion batteries (ZIBs) with great potential in the future energy storage market. However, the severe surface side reactions and dendrites affect the service lifespan and electrochemical performance of ZIBs. Herein, a bifunctional electrolyte additive, l-ascorbic acid sodium (LAA), has been added into ZnSO4 (ZSO) electrolyte (ZSO + LAA) to settle the above issues of ZIBs. On the one hand, the LAA additive tends to adsorb on the Zn anode surface to generate a H2O-resistive passivation layer, which can effectively isolate the H2O corrosion and regulate the Zn2+ ion 3D diffusion, thus inducing a uniform deposition layer. On the other hand, the strong adsorption capacity between LAA and Zn2+ can transform the solvated [Zn(H2O)6]2+ into [Zn(H2O)4LAA], thus reducing the coordinated H2O molecules and further suppressing side reactions. With this synergy effect, the Zn/Zn symmetric battery with the ZSO + LAA electrolyte can deliver a cycle life of 1200 h under 1 mA cm-2, and the Zn/Ti battery also presents an ultrahigh Coulombic efficiency of 99.16% under 1 mA cm-2, greatly superior to the batteries with the ZSO electrolyte. Additionally, the effectiveness of the LAA additive can be further verified in the Zn/MnO2 full battery and pouch cell.

A Rational Design of Silicon‐Based Anode for All‐Solid‐State Lithium‐Ion Batteries: A Review

Silicon is a promising alternative to the conventional graphite anode for lithium‐ion batteries (LIBs). However, pulverization of Si particles caused by volume expansion and formation of unstable solid electrolyte interphase can lead to several failure behaviors of LIBs. In contrast to LIBs employing liquid electrolytes, all‐solid‐state batteries (ASSBs) could exhibit totally different interfacial environments over Si anode materials, in terms of wetting properties of the Si surface by electrolyte. This characteristic interface of Si anode with solid‐state electrolyte (SSE) can change the electrochemical stability and long‐term life cycle performance of Si. In respect of commercialization, the incorporation of Si anode into ASSB could be the strongest approach to overcome the intrinsic limitations of anode materials. However, large contact losses between Si and SSE have to be handled in order to provide good electrochemical performance and stability. In this review, failure behaviors of Si anode within the SSE with proper characterization method is addressed and several design strategies for incorporation of Si anode into ASSB based on the following classifications are introduced: composite type and diffusion‐dependent type Si anodes. From this review, the possibility of Si anode for practical application to next‐generation ASSB by regulating its chemical and mechanical properties is suggested.

Silicon Nanoparticles Embedded in Chemical-Expanded Graphite through Electrostatic Attraction for High-Performance Lithium-Ion Batteries.

Silicon (Si) is a promising next-generation anode for high-energy-density lithium-ion batteries. The application of silicon/carbon (Si/C) composites with high Si content is hindered by the huge volume change and insecure electrochemical interface of the Si anode. Herein, chemical-expanded graphite (CEG) is used as a carbon matrix to form Si@CEG/C composites with an embedded structure. CEG with an abundant pore structure and electropositivity can well disperse and accommodate a mass of Si nanoparticles (Si NPs). With the flexibility and porosity of CEG, the embedded structure of Si NPs fixed in an expanded graphite layer can adopt the volume change of Si NPs and offer the abundant path of diffusion of lithium-ion, which leads to a moderate cycle and rate performance. Si@CEG/C exhibits a high reversible capacity of 1232.4 mA h g-1 at a current density of 0.5 A g-1 and with a capacity retention rate of 87% after 200 cycles. This embedded structure of Si/C composites built by CEG is meaningful for the structure design of the Si-based anode with higher specific capacity, active material utilization, and satisfactory cycle stability.

Effect of Polysulfide Speciation on Mg Anode Passivation in Mg-S Batteries.

Mg-S batteries are a promising next-generation system for beyond conventional Li-ion chemistry. The Mg-S architecture pairs a Mg metal anode with an inexpensive, high-capacity S8 cathode. However, S8-based cathodes exhibit the "polysulfide shuttle" effect, wherein soluble partially reduced Sx2- species generated at the cathode diffuse to and react with the anode. While dissolved polysulfides may undergo reactions to form Li+-permeable layers in Li-S systems, the interfaces on Mg anodes are passivating. In this work, we probe the reactivity of various Mg polysulfide solutions at the Mg anode interface. Mg polysulfide solutions are prepared without any chelating agents to closely mimic conditions in a Mg-S cell. The polysulfides are synthesized by reacting Mg metal and S8 in electrolyte, and the speciation is controlled by varying the Mg:S precursor ratio. S-poor precursor ratios produce magnesium polysulfide solutions with a higher proportion of short-chain polysulfides that react at the Mg anode faster than the longer-chain analogues. Anode passivation can be slowed by shifting the polysulfide equilibria toward longer-chain polysulfides through addition of S8.

Multidimensional visualization of the dynamic evolution of Limetal via insitu/operando methods.

The growing demands for high-energy density electrical energy storage devices stimulate the coupling of conversion-type cathodes and lithium (Li) metal anodes. While promising, the use of these "Li-free" cathodes brings new challenges to the Li anode interface, as Li needs to be dissolved first during cell operation. In this study, we have achieved a direct visualization and comprehensive analysis of the dynamic evolution of the Li interface. The critical metrics of the interfacial resistance, Li growth, and solid electrolyte interface (SEI) distribution during the initial dissolution/deposition processes were systematically investigated by employing multidimensional analysis methods. They include three-electrode impedance tests,in situ atomic force microscopy, scanning electrochemical microscopy, and cryogenic scanning transmission electron microscopy. The high-resolution imaging and real-time observations show that a loose, diffuse, and unevenly distributed SEI is formed during the initial dissolution process. This leads to the dramatically fast growth of Li during the subsequent deposition, deviating from Fick's law, which exacerbates the interfacial impedance. The compactness of the interfacial structure and enrichment of electrolyte species at the surface during the initial deposition play critical roles in the long-term stability of Li anodes, as revealed by operando confocal Raman spectroscopic mapping. Our observations relate to ion transfer, morphological and structural evolution, and Li (de)solvation at Li interfaces, revealing the underlying pathways influenced by the initial dissolution process, which promotes a reconsideration of anode investigations and effective protection strategies.

Guidelines for Impedance Analysis of Parent Metal Anodes in Solid‐State Batteries and the Role of Current Constriction at Interface Voids, Heterogeneities, and SEI

AbstractImpedance spectroscopy is widely used in operando studies of solid‐state batteries for characterizing charge transport and correlating it with structural features. A typical impedance spectrum reveals, in addition to transport signals of the solid electrolyte, one or more contributions due to processes taking place at the electrode interfaces. The focus of this study is on reversible (parent) metal anodes and a 3D electric network model is used to analyze the variation of their impedance as a function of pressure, temperature, or aging during cycling. This provides a recipe for experimentalists on how to identify impedance contributions arising from different interface effects, such as, charge transfer, dynamic current constriction, and solid electrolyte interphase formation. Rules are derived for assigning the different interface signals or identifying the dominant contribution in case of similar frequency‐dependence and a standard procedure for analysis is proposed. The suggested procedure is applied to experimental data of half cells where lithium metal is in contact with garnet‐type Li6.25Al0.25La3Zr2O12. This case study yields unambiguously that geometric current constriction due to morphological instabilities at the metal anode interface during cycling is the rate‐limiting step for this type of metal anode, rather than the frequently assumed polarization resistance of the electric charge transfer migration process.

Efficient cathodes for quasi-solid-state aluminum-air batteries

Different commercial carbonaceous materials, two made of activated carbons and one of multiwalled nanotubes, were used to prepare cathodes for primary aluminum-air cells and compared with the more expensive platinum-dispersed carbon, usually used as cathode for many types of metal-air cells. The aluminum-air cells used in the electrochemical tests were assembled with alkaline gel polymer electrolytes without any separator. Cells with cathodes made of a cheap activated carbon showed better electrochemical performances than those obtained with platinum-based cathodes. Notably, their discharge capacities were improved and the discharge voltages were always higher than 0.2 V. These improved performances were mainly attributed to the better electrocatalytic activity of the activated carbon as it results from polarization measurements, probably due to the presence of defects, as evidenced from Raman spectra. Three-electrode discharge tests were used to measure the electrode potentials and their impact to the overall cell electrochemical performances. During the discharge, in all cases, an increase of the anodic potential towards more positive values was observed, while the cathodic potential remained almost constant. Thus, the final failure of the cells was mainly due to the degradation of the anodic interface. This indicates the possibility to further increase the cell capacity by adopting suitable mitigation strategies of anodic parasitic reaction or different electrolyte design, with the final aim to realize efficient, cheap, and eco-friendly aluminum-air cells.