Al Batteries Research Articles

Functional Group-Driven Competing Mechanism in Electrochemical Reaction and Adsorption/Desorption Processes toward High-Capacity Aluminum-Porphyrin Batteries.

Nonaqueous organic aluminum batteries are considered as promising high-safety energy storage devices due to stable ionic liquid electrolytes and Al metals. However, the stability and capacity of organic positive electrodes are limited by their inherent high solubility and low active organic molecules. To address such issues, here porphyrin compounds with rigid molecular structures present stable and reversible capability in electrochemically storing AlCl2 +. Comparison between the porphyrin molecules with electron-donating groups (TPP-EDG) and with electron-withdrawing groups (TPP-EWG) suggests that EDG is responsible for increasing both highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, resulting in decreased redox potentials. On the other hand, EWG is associated with decreasing both HOMO and LUMO energy levels, leading to promoted redox potentials. EDG and EWG play critical roles in regulating electron density of porphyrin π bond and electrochemical energy storage kinetics behavior. The competitive mechanism between electrochemical redox reaction and de/adsorption processes suggests that TPP-OCH3 delivers the highest specific capacity ~171.8 mAh g-1, approaching a record in the organic Al batteries.

Functional Group‐Driven Competing Mechanism in Electrochemical Reaction and Adsorption/Desorption Processes toward High‐Capacity Aluminum‐Porphyrin Batteries

AbstractNonaqueous organic aluminum batteries are considered as promising high‐safety energy storage devices due to stable ionic liquid electrolytes and Al metals. However, the stability and capacity of organic positive electrodes are limited by their inherent high solubility and low active organic molecules. To address such issues, here porphyrin compounds with rigid molecular structures present stable and reversible capability in electrochemically storing AlCl2+. Comparison between the porphyrin molecules with electron‐donating groups (TPP‐EDG) and with electron‐withdrawing groups (TPP‐EWG) suggests that EDG is responsible for increasing both highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, resulting in decreased redox potentials. On the other hand, EWG is associated with decreasing both HOMO and LUMO energy levels, leading to promoted redox potentials. EDG and EWG play critical roles in regulating electron density of porphyrin π bond and electrochemical energy storage kinetics behavior. The competitive mechanism between electrochemical redox reaction and de/adsorption processes suggests that TPP‐OCH3 delivers the highest specific capacity ~171.8 mAh g−1, approaching a record in the organic Al batteries.

Low-cost ionic liquid electrolytes based on low-molecular-weight primary and secondary alkylamine hydrochlorides for rechargeable Al batteries

Rechargeable batteries with Al metal as the negative electrode are promising candidates for post‑lithium-ion batteries. However, the cost of the most commonly used electrolytes, chloroaluminate ionic liquids based on 1-ethyl-3-methylimidazolium chloride (EMICl), is prohibitive. Herein, we report a novel, low-cost chloroaluminate ionic liquid electrolyte based on primary and secondary alkylamine hydrochlorides, namely, ethylamine hydrochloride (EtNH3Cl) and dimethylamine hydrochloride (Me2NH2Cl). The advantages of these alkylamine hydrochlorides over their tertiary amine counterparts (Me3NHCl and Et3NHCl) are their lower cost, odorless nature, and a lower molecular weight that would reduce the battery weight. Although the binary systems of EtNH3Cl–AlCl3 and Me2NH2Cl–AlCl3 are not liquids at room temperature, mixing the two systems results in an ionic liquid at room temperature. The electrodeposition of Al and intercalation of AlCl4− into graphite in this electrolyte system are demonstrated. The alkylammonium cations decompose only at potentials below −0.3 V vs. Al. The performance of Al–graphite batteries incorporating this low-cost electrolyte is comparable to that of batteries using the conventional expensive EMICl-based electrolytes under typical charge-discharge conditions. The low-cost EtNH3Cl–Me2NH2Cl–AlCl3 electrolyte is expected to advance Al batteries toward practical application and commercialization.

Boosting Aluminum Storage in Highly Stable Covalent Organic Frameworks with Abundant Accessible Carbonyl Groups

AbstractAluminum batteries employing organic electrode materials present an appealing avenue for sustainable and large‐scale energy storage. Nevertheless, conventional organic materials encounter limitations due to their restricted active sites, known instability, and sluggish redox kinetics. In this study, a redox‐active covalent organic framework supported by CNT is reported, enriched with substantial C═O groups, as an advanced cathode material for Al‐organic batteries. Theoretical simulation and ex situ analysis unveil the pivotal roles of C═O groups in effectively storing AlCl2+. As a result, Al batteries with the organic cathode exhibit a specific capacity of 290 mAh g−1 at 0.2 A g−1 and outstanding rate performance. Furthermore, it retains a reversible capacity of 170 mAh g−1 even after 32 000 cycles at 10 A g−1 and attains an energy density of 389 Wh kg−1. The remarkable performance stems not only from the abundant C═O and C─N groups enabling the storage of multiple AlCl2+ by the favorable pseudocapacitive process, but also from the synergistic interplay between the robust COF network and the conductive CNT channels that significantly enhances structural stability and accelerates ion/electron diffusion. This work stands to inspire further research in the pursuit of stable organic cathodes, fostering designs with plentiful accessible redox‐active sites to boost energy storage capabilities.

π‐Conjugated Metal Free Porphyrin as Organic Cathode for Aluminum Batteries

AbstractNowadays, Al (dual) batteries are mainly based on graphite cathode materials. Besides this material, the limited life cycle and the rate performance of other possible cathode materials have hampered the development of practical and sustainable rechargeable aluminium batteries (RABs). Herein, we report an organic A4‐metal‐free porphyrin system bearing diphenylamimo‐phenyl functional units as an Al‐storage cathode material, which is capable of delivering a reversible capacity of 83 mAh g−1 at 1 A g−1 after 200 cycles and displays a good cycling stability. Achieving such high rate performance opens a pathway to developing practical sustainable cathodes for aluminium batteries.

Solvation Structure Regulation for Highly Reversible Aqueous Al Metal Batteries.

Metallic Al has been deemed an ideal electrode material for aqueous batteries by virtue of its abundance and high theoretical capacity (8056 mAh cm-3). However, the development of aqueous Al metal batteries has been hindered by several side reactions, including water decomposition, Al corrosion, and passivation, which arise from the solvation reaction of Al and H2O in conventional aqueous electrolytes. In this work, we report that water activity in electrolyte can be suppressed by optimizing the Al3+ solvation structure through intercalation of polar pyridine-3-carboxylic acid in an aluminum trifluoromethanesulfonate aqueous environment. Furthermore, the pyridine-3-carboxylic acid molecules are inclined to alter the surface energy of Al, thus suppressing the random deposition of Al. As a result, the Al corrosion in the hybrid electrolyte is restrained, and the long-term electrochemical stability of the electrolyte is tremendously improved. These merits bring remarkable reversibility to aqueous Al batteries using Al-preintercalated MnO2 cathodes, delivering a retaining energy density of >250 Wh kg-1 at 0.2 A g-1 after 600 cycles.

Morphology Dependent Electrochemical Performance of Hydrothermally Synthesized Birnessite-Type Manganese Dioxide in Aqueous Aluminum Ion Batteries

Three distinct morphologies of δ-MnO2, including a mixed morphology with nanofibers and nanosheets, smaller nanosheets, and larger, more organized nanosheets, were synthesized by controlling the hydrothermal synthesis parameters. The aim is to use these materials in aqueous aluminum ion batteries (AIBs). The materials were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). The electrochemical performance of the δ-MnO2 electrodes was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques.It was found that the morphology of the δ-MnO2 had a significant impact on the electrochemical properties of AIBs. Specifically, among the δ-MnO2|0.5 M Al2(SO4)3 0.4MMnSO4|Al batteries, the δ-MnO2 with larger, more organized nanosheets exhibited the highest specific capacity of 320 mAh/g, followed by the mixed morphology (213 mAh/g), and the smaller nanosheets (140 mAh/g). Furthermore, the δ-MnO2 with smaller nanosheets demonstrated the best capacity retention over 70 cycles, retaining 98% of its initial capacity, while the δ-MnO2 with larger, more organized nanosheets exhibited the lowest capacity retention, retaining only 9.3% of its initial capacity after 70 cycles.In conclusion, this study highlights the impact of the δ-MnO2 morphology on the electrochemical properties of AIBs, with smaller nanosheets exhibiting superior performance in terms of capacity retention. These findings could be valuable for the rational design and optimization of high-performance AIB electrodes.Keywords: aqueous aluminum ion batteries, manganese dioxide

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.

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.

Optimization of an Artificial Solid Electrolyte Interphase Formed on an Aluminum Anode and Its Application in Rechargeable Aqueous Aluminum Batteries.

Electrochemical cells that incorporate aluminum (Al) as the active material have become increasingly popular due to the advantages of high energy density, cost-effectiveness, and superior safety features. Despite the progress made by research groups in developing rechargeable Al//MxOy (M = Mn, V, etc.) cells using an aqueous Al trifluoromethanesulfonate-based electrolyte, the reactions occurring at the Al anode are still not fully understood. In this study, we explore the artificial solid electrolyte interphase (ASEI) on the Al anode by soaking it in AlCl3/urea ionic liquid. Surprisingly, our findings reveal that the ASEI actually promotes the corrosion of Al by providing chloride anions rather than facilitating the transport of Al3+ ions during charge/discharge cycles. Importantly, the ASEI significantly enhances the cycling stability and activity of Al cells. The primary reactions occurring at the Al anode during the charge/discharge cycle were determined to be irreversible oxidation and gas evolution. Furthermore, we demonstrate the successful realization of urea-treated Al (UTAl)//AlxMnO2 cells (discharge operating voltage of ∼1.45 V and specific capacity of 280 mAh/g), providing a platform to investigate the underlying mechanisms of these cells further. Overall, our work highlights the importance of ASEI in controlling the corrosion of Al in aqueous electrolytes, emphasizing the need for the further development of electrolytic materials that facilitate the transport of Al3+ ions in rechargeable Al batteries.

Manganese oxides as positive electrode materials for rechargeable aluminum batteries

Three composites of carbon and amorphous MnO2, crystalline α-MnO2, or Mn2O3 were synthesized and investigated as the positive electrode materials for rechargeable Al batteries. For amorphous MnO2 and crystalline Mn2O3, the maximum discharge capacity was about 300 mAh g−1, which is the highest capacity among nonaqueous rechargeable Al batteries using manganese oxide positive electrodes. The amorphous MnO2 electrode showed a discharge capacity of more than 150 mAh g−1 even after 10 charge-discharge cycles. Crystal structure analysis and electronic state analysis suggested that crystalline Mn2O3 changed to amorphous MnO2 during the first charge process. These results suggest that the amorphous MnO2/carbon composite can be an excellent positive electrode material for rechargeable Al batteries.

Stable Low-Temperature Al Batteries Enabled by Integrating Polydopamine-Derived N-Doped Carbon Nanospheres With Flake Graphite.

The battery performance declines significantly in severely cold areas, especially discharge capacity and cycle life, which is the most significant pain point for new energy consumers. To address this issue and improve the low-temperature characteristic of aluminum-ion batteries, in this work, polydopamine-derived N-doped carbon nanospheres are utilized to modify the most promising graphite material. More active sites are introduced into graphite, more ion transport channels are provided, and improved ionic conductivity is achieved in a low-temperature environment. Due to the synergistic effect of the three factors, the ion diffusion resistance is significantly reduced and the diffusion coefficient of aluminum complex ions in the active material become larger at low temperatures. Therefore, the battery delivers an improved capacity retention rate from 23% to 60% at -20 °C and excellent ultra-long cycling stability over 5500 cycles at -10 °C. This provides a novel strategy for constructing low-temperature aluminum-ion batteries with high energy density, which is conducive to promoting the practicality of aluminum-ion batteries.

A Carbon Aerogel Lightweight Al Battery for Fast Storage of Fluctuating Energy.

Al batteries have great potential for renewable energy storage owing to their low cost, high capacity, and safety. High energy density and adaptability to fluctuating electricity are major challenges. Here, a lightweight Al battery for fast storage of fluctuating energy is constructed based on a novel hierarchical porous dendrite-free carbon aerogel film (CAF) anode and an integrated graphite composite carbon aerogel film (GCAF) cathode. A new induced mechanism by the O-containing functional groups on the CAF anode is con-firmed for uniform Al deposition. The GCAF cathode possesses a higher mass utilization ratio due to the extremely high loading mass (9.5-10.0mg cm-2 ) of graphite materials compared to conventional coated cathodes. Meanwhile, the volume expansion of the GCAF cathode is almost negligible, resulting in better cycling stability. The lightweight CAF‖GCAF full battery can adapt well to large and fluctuating current densities owing to its hierarchical porous structure. A large discharge capacity (115.6 mAh g-1 ) after 2000 cycles and a short charge time (7.0min) at a high current density are obtained. The construction strategy of lightweight Al batteries based on carbon aerogel electrodes can promote the breakthrough of high-energy-density Al batteries adapted to the fast storage of fluctuating renewable energy.

Anode‐Free Aluminum Electrode with Ultralong Cycle Life and High Coulombic Efficiency Exceeding 99.92% Enabled by a Lattice‐Matching Layer

AbstractMetallic aluminum is an attractive anode owing to its high specific capacity, earth abundance, and low cost. However, the poor reversibility of Al deposition/dissolution and Al dendrites have impeded its deployment. Herein, a strategy for constructing a lattice‐matching layer (LML) to regulate the behavior of Al deposition/dissolution is demonstrated. Various experiments and theoretical calculations validate that gold LML as an example can significantly enhance the nucleation density and reduce average particle size, which achieve highly reversible, dendrite‐free, durable, and anode‐free Al anodes. The metallic Al shows stable Al deposition/dissolution on Au@Ti substrate for more than 4500 h with an average Coulombic efficiency of 99.92%, which is a record‐high reported value. Furthermore, the anode‐free full cell based on Au@Ti anode and expanded graphite cathode exhibits outstanding long‐term stability for 900 cycles with the capacity retention rate of 80%. This study provides an effective strategy to enhance the reversibility and utilization of the Al anode, which provides inspiration for advanced Al batteries.

Understanding the reversible electrodeposition of aluminum in low-cost room-temperature molten salts

Aluminum is the most earth-abundant metal, is trivalent, is inert in ambient humid air, and has a density approximately four-times that of lithium at room temperature. These attributes make it an attractive material for cost-effective, long-duration storage of electrical energy in batteries. Scientific discoveries in the past decade have established that secondary Al batteries can be created by paring an Al anode with a graphite or transition metal oxide cathode, in imidazolium-based, room-temperature ionic-liquid-Aluminum chloride electrolytes. Here we report findings from a systematic study that sheds light on the structural requirements, physicochemical, and transport properties of the ionic liquid electrolytes responsible for the high reversibility of Al battery anodes. We find that the most important interfacial and transport properties of these electrolytes can be achieved in other electrolytes, including ammonium-based molten salts that are available at costs as much as twenty-times lower than the ionic liquid-Aluminum chloride melt. High Al reversibility in ammonium- and imidazolium-based electrolytes is specifically shown to require a critical ratio of the solvation species, where Lewis acidity and beneficial interfacial reactions continuously etch the alumina resistive interfacial layer and form beneficial solid electrolyte interphase at the anode. We report further that successful development of new electrolyte families that support high Al anode reversibility also provides a good platform for detailed studies of the working mechanisms of an intercalation graphite cathode using X-ray absorption spectroscopy. Our findings therefore open new opportunities for developing simple, cost-effective, room-temperature Al batteries that enable long-duration electrical energy storage.

Yolk-shell structured MoS2/NiS@S heterojunction for high-performance rechargeable Al batteries

In recent years, thanks to the excellent safety performance and extremely high theoretical specific capacity of rechargeable Al batteries, the development of Al battery cathode materials has become extremely competitive. In the structural design of cathode materials, the yolk-shell structure has a large amount of storage space and abundant active sites, giving full play to the advantages of synergy in building high-performance cathode structures. The construction of MoS2/NiS@S heterojunction interface effectively improves the conductivity of monometallic sulfide as cathode and improves the discharge performance of the electrode. The surface folds and pores of the heterojunction provide excellent channels for the free insertion and release of Al3+, reducing binding energy and enhancing Al3+ binding efficiency. It has maintained a reversible capacity of 130.19 mAh g−1 at 500 mA g−1 after 2000 cycles. This provides additional ideas for the development of transition metal sulfide materials in Al batteries.

Reversible aqueous aluminum metal batteries enabled by a water-in-salt electrolyte

Aluminum (Al), the most abundant metallic element on the earth crust, has been reckoned as a promising battery material for its the highest theoretical volume capacity (8046 mAh cm−3). Being rechargeable in ionic liquid electrolytes, however, the Al anode and battery case suffer from corrosion. On the other hand, Al is irreversible in aqueous electrolyte with severe hydrogen evolution reaction. Here, we demonstrate a water-in-salt aluminum ion electrolyte (WISE) based on Al and lithium salts to tackle the above challenges. In the WISE system, water molecules can be confined within the Li+ solvation structures. This diminished Al3+-H2O interaction essentially eliminates the hydrolysis effect, effectively protecting Al anode from corrosion. Therefore, long-term Al plating/stripping can be realized. Furthermore, two types of high-performance full batteries have been demonstrated using copper hexacyanoferrate (CuHCF, a Prussian Blue Analogues) and LiNi0.8Co0.1Mn0.1O2 (NCM) as cathodes. The reversibility of Al anode laid the foundation for low cost rechargeable batteries suffering for large-scale energy storage.Broader context: Al batteries are expected to become a safe and sustainable alternative to lithium batteries. For decades, chase for a feasible Al secondary battery has not been successful. The key challenge is to find suitable cathode and electrolyte materials, together with which Al anode battery can function reversibly. Currently, fatal drawbacks have impeded the practical application of Al metal batteries (AMBs), such as sustained corrosion of Al anode and battery case in ionic liquid electrolytes, irreversibility issues as well as severe hydrogen evolution reaction during cycling in aqueous electrolyte. Therefore, electrolyte and their electrochemical kinetics play a vital role in the performance and environmental operating limitations of high-energy Al metal batteries. In this work, we demonstrate a nearly neutral Al ion water-in-salt electrolyte (WISE) to tackle the above challenges. The WISE shows excellent stability in the open atmosphere. The distinct solvation-sheath structure of Al3+ in the WISE system would protect Al metal anodes from corrosion and eliminate hydrogen evolution reaction effectively, further promoting the reversibility of Al metal anodes with dendrite-free morphology. Moreover, such a WISE exhibits superior compatibility with LiNi0.3Co0.3Mn0.3O2 (NCM) and copper hexacyanoferrate (CuHCF) cathodes and long-term stabilities with high coulombic efficiency (CE) can be attained for full batteries with the WISE. The approach in this study can furnish an opportunity to develop reversible AMBs and lay the foundation for other potential multivalent-metal-based secondary batteries suffering from interface passivation and poor reversibility, which suggest the promise of multivalent metal batteries and their applications in large-scale energy storage.

A high-purity AgO cathode active material for high-performance aqueous AgO–Al batteries

The aqueous divalent silver oxide (AgO)-aluminum (Al) batteries have garnered international attention due to the advantages of high safety, high specific energy, and environmental friendliness. However, the low purity of the AgO used as the cathode material shortens the battery's storage life and causes two voltage plateaus during discharge. Herein, we employ a quick and efficient approach to make AgO for aqueous AgO–Al batteries' cathode active material. The outcomes exhibit the successful production of high purity AgO with good thermal stability. The prepared AgO cathode additionally displays an excellent specific capacity of 394.7 mAh g−1, and the plateau of the discharge profile is closed to 1.7 V at the current density of 500 mA cm−2, taking advantage of the good electronic conductivity and charge transfer kinetics. A maximum output power density of 1260.54 mW cm−2 at 900 mA cm−2 is also possible. Furthermore, the electrochemical mechanism of the AgO electrode is further uncovered by Ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) studies. Thus, this research presents a viable possibility for the fabrication of aqueous AgO–Al batteries by demonstrating the use of high purity AgO as a cathode active material.

Nb2CTx MXene Cathode for High-Capacity Rechargeable Aluminum Batteries with Prolonged Cycle Lifetime.

Aluminum-ion batteries have garnered significant interest as a potentially safer and cheaper replacement for conventional lithium-ion batteries, offering a shorter charging time and denser storage capacity. Nonetheless, the progress in this field is considerably hampered by the limited availability of suitable cathode materials that can sustain the reversible intercalation of Al3+/[AlCl4]- ions, particularly after long cycles. Herein, we demonstrate that rechargeable Al batteries embedded with two-dimensional (2D) Nb2CTx MXene as a cathode material exhibit excellent capacity and exceptional long cyclic performance. We have successfully improved the initial electrochemical performance of Nb2CTx MXene after being properly delaminated to a single-layered microstructure and subjected to a post-synthesis calcining treatment. Compared to pristine Nb2CTx MXene, the Al battery embedded with the calcined Nb2CTx MXene cathode has, respectively, retained high capacities of 108 and 80 mAh g-1 after 500 cycles at current densities of 0.2 and 0.5 A g-1 in a wide voltage window (0.1-2.4 V). Noteworthily, the cyclic lifetime of Nb2CTx MXene was extended from ∼300 to >500 times after calcination. We reveal that attaining Nb2CTx nanosheets with a controllable d-spacing has promoted the migration of the [AlCl4]- and Al3+ ions in the MXene interlayers, leading to enhanced charge storage. Furthermore, we found out that the formation of niobium oxides and amorphous carbon after calcination probably benefits the electrochemical performance of Nb2CTx MXene electrode in Al batteries.

Uneven deposition on the Al electrode under tension strain

Structural deformation and dendrite formation, which would impact the electrochemical processes of rechargeable metal batteries, are usually observed in the high-energy density metal electrodes. Herein, we design an in-situ optical mechano-electrochemical system to study Al deposition on the Al electrode in non-aqueous Al batteries under non-uniform strain. Inhomogeneous distribution of applied strain is realized by creating an oval hole in the Al electrode. The results of the in-situ experiments suggest that the dense Al deposition, which is related to the evolution of surface morphology and increasing reactive sites, is achieved in the regions of stress concentration. The evolution of surface morphology is monitored by the in-situ tension experiments using scanning electron microscope and atomic force microscope. Besides, a qualitative mathematical model is employed to analyze the changes of the local reaction rate owing to the changed surface morphology and the cracks of oxide film under tensile stress. The results are useful to understand the Al deposition when the mechanical force is applied to the metal electrode.