Al-ion Batteries Research Articles

Ion storage performance of a polymer for mono-, di- and tri-valent metal ions in non-aqueous electrolytes.

A cost-effective quinone-pyrrole conjugated polymer is utilized as an electrode for non-aqueous Al, Zn and Li-ion batteries. Reversible capacities of 120 mA h g-1 at 50 mA g-1 for Al-ion batteries and 108 and 175 mA h g-1 for Zn and Li-ion batteries, respectively, at 100 mA g-1 are observed. Thousands of stable cycles were obtained at 1000 mA g-1 current density, providing sufficient evidence for a range of applications of the polymer in electrochemical energy storage.

Rational engineering of VS4 nanorod array on rose-shaped VS2 nanosheets for high-performance aluminium-ion batteries.

High performance aluminium-ion (Al-ion) batteries are of wide interest owing to the high theoretical capacity, abundance of Al metal and good safety. Here, we develop a hierarchical VS2@VS4 composed of a VS4 nanorod array in situ grown on VS2 rose-shaped nanosheets that displays a good electrochemical performance. The VS2@VS4 cathode displays a high capacity of 162.7 mA h g-1 after 200 cycles at -10 °C, and keeps 116.5 mA h g-1 after 500 cycles at room temperature. Rate-performance at -10 °C shows a capacity retention rate of 90%, which indicates the potential for engineering high-performance energy-storage composites.

A lamellar V2O3@C composite for aluminium-ion batteries displaying long cycle life and low-temperature tolerance.

Rechargeable aluminum-ion (Al-ion) batteries have important potential for fast charging and safe energy-storage systems. Here, we develop a composite composed of lamellar V2O3@C nanosheets, which displays high electrochemical properties as an Al-ion battery cathode. The unique structure is conducive to the rapid insertion and release of Al3+ ions, electrolyte infiltration, and improved conductivity. After cycling 500 times, the capacity exceeds 242.5 mA h g-1. Under a low temperature of -10 °C, the capacity remains 150.8 mA h g-1, and the Coulombic efficiency is higher than 98.8%. The V2O3@C also exhibits a good reversibility verified by using ex situ X-ray powder diffraction patterns, while the constant current intermittent titration technology shows a low reaction barrier, which indicates that the lamellar composite presented here could find significant applications for engineering many high-performance energy-storage systems.

Unraveling the multivalent aluminium-ion redox mechanism in 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA).

Rechargeable Aluminium-organic batteries are an exciting emerging energy storage technology owing to their low cost and promising high performance, thanks to the ability to allow multiple-electron redox chemistry and multivalent Al-ion intercalation. In this work, we use a combination of Density Functional Theory (DFT) calculations and experimental methods to examine the mechanism behind the charge-discharge reaction of the organic dye 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) in the 1,3-ethylmethylimidazolium (EMIm+) chloroaluminate electrolyte. We conclude that, contrary to previous reports claiming the intercalation of trivalent Al3+, the actual ionic species involved in the redox reaction is the divalent AlCl2+. While a less-than-ideal scenario, this mechanism still allows a theoretical transfer of four electrons per formula unit, corresponding to a remarkable specific capacity of 273 mA h g-1. However, the poor reversibility of the reaction and low cycle life of the PTCDA-based cathode, due to its solubility in the electrolyte, make it an unlikely candidate for a commercial application.

H-MoO3/AlCl3-Urea/Al: High performance and low-cost rechargeable Al-ion battery

A completely functional rechargeable aluminium – ion battery (AIB) operating at room temperature based on hexagonal molybdenum oxide (h-MoO3) as positive electrode active material and AlCl3-Urea as electrolyte has been developed. This is the first demonstration of the compatibility between a metal oxide and a urea based electrolyte in an AIB. Our battery shows a good electrochemical performance by using this low-cost, eco-friendly, positive electrode - electrolyte system with low corrosion properties. Thanks to an exhaustive study carried out by using different characterization techniques (XRD, micro-Raman, CV), it has been observed that h-MoO3 is capable of efficiently inserting and de-inserting the redox active species in its crystalline structure by means of controlled diffusion processes. When combined with a suitable amount of carbon nanotubes, the capacitive properties of this material are enhanced, obtaining batteries with a pseudo-capacitive behaviour. This battery reaches specific capacity values ∼100 mA h g−1 at current densities of 100 mA g−1 and ∼45 mA h g−1 at current densities of 500 mA g−1, always with efficiencies higher than 90%. The obtained results pave the way for the commercialisation of these energy storage devices, providing a promising and simple strategy for the development of high performance, low-cost and non-corrosive AIBs.

Non-aqueous Al-ion batteries: cathode materials and corresponding underlying ion storage mechanisms

Non-aqueous Al-ion batteries: cathode materials and corresponding underlying ion storage mechanisms

Paper-based aqueous Al ion battery with water-in-salt electrolyte

Low-cost, flexible and safe battery technology is the key to the widespread usage of wearable electronics, among which the aqueous Al ion battery with water-in-salt electrolyte is a promising candidate. In this work, a flexible aqueous Al ion battery is developed using cellulose paper as substrate. The water-in-salt electrolyte is stored inside the paper, while the electrodes are either printed or attached on the paper surface, leading to a lightweight and thin-film battery prototype. Currently, this battery can tolerate a charge and discharge rate as high as 4 A g−1 without losing its storage capacity. The charge voltage is around 2.2 V, while the discharge plateau of 1.6–1.8 V is among the highest in reported aqueous Al ion batteries, together with a high discharge specific capacity of ∼140 mAh g−1. However, due to the water electrolysis side reaction, the faradaic efficiency can only reach 85% with a cycle life of 250 due to the dry out of electrolyte. Benefited from using flexible materials and aqueous electrolyte, this paper-based Al ion battery can tolerate various deformations such as bending, rolling and even puncturing without losing its performance. When two single cells are connected in series, the battery pack can provide a charge voltage of 4.3 V and a discharge plateau as high as 3–3.6 V, which are very close to commercial Li ion batteries. Such a cheap, flexible and safe battery technology may be widely applied in low-cost and large-quantity applications, such as RFID tags, smart packages and wearable biosensors in the future.

High‐Energy SWCNT Cathode for Aqueous Al‐Ion Battery Boosted by Multi‐Ion Intercalation Chemistry (Adv. Energy Mater. 39/2021)

Aqueous Al-Ion Batteries In article number 2101514, Xinhua Liu, Dennis Y. C. Leung, and co-workers propose a high-performance aqueous Al-ion battery with a SWCNT cathode and an aluminum foil anode. A water-in-salt electrolyte is used to provide multiple electrochemical species so that AlCl4− ions can be extracted and Al3+ ions can be inserted from/into the SWCNT cathode during discharging, providing a high-energy-density output. This low-cost battery technology is expected to be utilized for large-scale renewable energy storage systems.

Novel K2Ti8O17 Anode via Na+/Al3+ Co-Intercalation Mechanism for Rechargeable Aqueous Al-Ion Battery with Superior Rate Capability.

A promising aqueous aluminum ion battery (AIB) was assembled using a novel layered K2Ti8O17 anode against an activated carbon coated on a Ti mesh cathode in an AlCl3-based aqueous electrolyte. The intercalation/deintercalation mechanism endowed the layered K2Ti8O17 as a promising anode for rechargeable aqueous AIBs. NaAc was introduced into the AlCl3 aqueous electrolyte to enhance the cycling stability of the assembled aqueous AIB. The as-designed AIB displayed a high discharge voltage near 1.6 V, and a discharge capacity of up to 189.6 mAh g−1. The assembled AIB lit up a commercial light-emitting diode (LED) lasting more than one hour. Inductively coupled plasma–optical emission spectroscopy (ICP-OES), high-resolution transmission electron microscopy (HRTEM), and X-ray absorption near-edge spectroscopy (XANES) were employed to investigate the intercalation/deintercalation mechanism of Na+/Al3+ ions in the aqueous AIB. The results indicated that the layered structure facilitated the intercalation/deintercalation of Na+/Al3+ ions, thus providing a high-rate performance of the K2Ti8O17 anode. The diffusion-controlled electrochemical characteristics and the reduction of Ti4+ species during the discharge process illustrated the intercalation/deintercalation mechanism of the K2Ti8O17 anode. This study provides not only insight into the charge–discharge mechanism of the K2Ti8O17 anode but also a novel strategy to design rechargeable aqueous AIBs.

High-Performance MnO2 /Al Battery with In Situ Electrochemically Reformed Alx MnO2 Nanosphere Cathode.

Aqueous Al-ion battery (AAIB) is regarded as a promising candidate for large-scale energy storage systems due to its high capacity, high safety, and low cost, with MnO2 proved to be a high-performance cathode. However, the potential commercial application of this type of battery is plagued by the frequent structural collapse of MnO2 . Herein, an in situ, electrochemically reformed, urchin-like Alx MnO2 cathode is developed for water-in-salt electrolyte-based AAIBs. Benefiting from its unique α-MnO2 coated Mn2 AlO4 structure, a high Al ion storage capacity is achieved together with a high discharge voltage plateau of 1.9V by reversible MnO2 electrolysis. Consequently, the battery exhibits a high specific capacity of 285 mAh g-1 and a high energy density of 370Wh kg-1 at a high current density of 500mA g-1 . Improved stability with record capacity retention is also obtained at an ultrahigh current density of 5 A g-1 after 500 cycles. Such a high-capacity and high-stability Alx MnO2 cathode would pave the way for in situ electrochemical transformation of cathode design and thus boost the practical application of AAIBs.

Cleaner Energy Storage: Cradle-to-Gate Life Cycle Assessment of Aluminum-Ion Batteries With an Aqueous Electrolyte

In the context of growing demand on energy storage, exploring the holistic sustainability of technologies is key to future-proofing our development. In this article, a cradle-to-gate life cycle assessment of aqueous electrolyte aluminum-ion (Al-ion) batteries has been performed. Due to their reported characteristics of high power (circa 300 W kg−1 active material) and low energy density (circa 15 Wh kg−1 active material), these results were compared with those of supercapacitors (per kW). Initial findings suggest these aluminum-ion cells have fewer environmental impacts than commercial supercapacitors, hence offering a more environmentally sensitive energy storage technology solution. Al-ion batteries are in their early development, and this result shows a strong argument for continuing research into this technology alongside other emerging energy storage systems.

Modelling aluminium energy storage systems comprising ionic liquid and aqueous electrolyte cells: Case studies in high-performance electric vehicles

This paper models hybrid energy storage systems (HESSs) composed of ionic liquid Al-ion batteries (ILAIBs) and aqueous Al-ion batteries (AAIBs) for electric vehicle (EV) propulsion. Al-ion batteries are being developed as alternatives to existing battery technologies as Al is an abundant, non-toxic material. Al-ion batteries can be tailored for high power density or high energy density and as such are suitable for HESSs for EVs. In this paper, Al-based chemistries are substituted for one or both of the Li-ion battery (LIB) and supercapacitor (SC) components of the benchmark LIB-SC HESS, and thus the ILAIB-SC, LIB-AAIB, and ILAIB-AAIB HESSs are proposed and modelled with a high-performance EV. The performance of each HESS is compared with that of the conventional LIB-SC HESS, in terms of mass, volume, initial costs, and vehicle lifetime costs. Results show that using the ILAIB as the main energy storage in the HESS can reduce vehicle lifetime costs by 16% as compared with the LIB-based HESSs, but the volume of ILAIB-based HESSs is ten times that of LIB-based HESS. Using the AAIB as the second energy storage can reduce vehicle lifetime costs by 2% but also benefit from 2% less mass and 1% less volume as compared with the SC-based HESSs. Considering both financial costs and feasibility of deployment, the LIB-AAIB HESS is the most viable hybrid combination for high-performance EV propulsion at the present stage.

In situ polymerized solid electrolytes for superior safety and stability of flexible solid-state Al-ion batteries

Research on pouch-type or flexible batteries is currently being conducted with the increasing interest in flexible devices. However, lithium-ion batteries using liquid electrolytes, which are currently the most widely used, have limitations in terms of lithium reserves and the use of flammable organic electrolytes. To solve this problem, research is being actively conducted on Al-ion batteries (AIBs) that are highly safe and capable of fast charge/discharge. In this study, gel polymer electrolytes (GPEs) were developed by in-situ polymerization of ethyl acrylates in AlCl3/[EMIm]Cl ionic liquids. AIBs with GPEs as a solid-state electrolyte medium can solve the crucial problems in current liquid AIB systems, including electrolyte leakage, anode corrosion, and moisture sensitivity. AIBs with GPEs exhibit a reasonable energy storage capacity of 90 mAh g−1 even at a high current density of 200 mA g−1 with a high coulombic efficiency of 95%. Additionally, they exhibit a high long-term stability over 500 cycles without capacity reduction. Furthermore, AIBs demonstrate exceptional operational stability and safety under harsh operating conditions, such as folding, bending, and cutting. These results suggest that new solid-state AIBs based on GPEs provide a promising strategy for the development of high-performance solid-state flexible rechargeable battery systems.

Suppressing passivation layer of Al anode in aqueous electrolytes by complexation of H2PO4− to Al3+ and an electrochromic Al ion battery

Aqueous aluminum ion batteries (AIBs) are attractive alternatives for post-lithium energy storage systems. However, the short lifespan seriously limits the development of AIBs, arising from the formation of a passivation layer on the Al electrode surface as well as the strong electrostatic interaction between bulky Al3+ ions and host materials. Herein, we developed a hybrid electrolyte based on aluminum trifluoromethanesulphonate (Al(TOF)3) and H3PO4 which can effectively alleviate the passivation and exhibit superior stability. A full aqueous AIB based on this electrolyte and polyaniline (PANI) cathode exhibits a record-breaking lifespan of 3850 cycles and superior rate capability. Mechanism study suggests that Al3+ ions are bonded to both the H2PO4− and TOF− to form complex ions Al(H2PO4−)x(TOF−)y+(H2O)n, which can mitigate the strong charge densities of trivalent Al3+ and contribute to fast reaction kinetics. Besides, the ex-situ study reveals that PANI cathode experiences a co-intercalation/deintercalation process of Al(H2PO4−)x(TOF−)y+(H2O)n, TOF−, and H+ during the charging/discharging process with high reversibility and stability. As a proof of concept, an electrochromic Al//PANI battery is fabricated, which combines both electrochromism and energy storage and delivers a higher coloration efficiency of 84 cm2C−1 at a wavelength of 630 nm. This work presents an effective and facile strategy to developing long-life aqueous Al//PANI batteries and may promote the application of AIBs with electrochromic function.

Computational investigation of 2D 3d/4d hexagonal transition metal borides for metal-ion batteries

Two-dimensional (2D) transition metal borides (MBs) with rich diversity and intrinsic high conductivity attract increasingly focus in energy storage fields. Herein, seven structures (Sc2B2, Ti2B2, V2B2, Cr2B2, Zr2B2, Nb2B2, Mo2B2) were screened from one interesting class of 2D hexagonal 3d/4d M2B2 monolayers to be promising anode materials for Li-/Mg-/Al-ion battery using first principles calculations. Phonon dispersions, energy calculations, configuration analyses, electronic structure analyses and ab initio molecular dynamics simulations confirm their high dynamic stability, strong adsorption capability and low volume change (< 7%) for Li/Mg/Al storage, and good thermostability with two layers of charge carriers. Furthermore, the high capacities (252–480/504–960/753–1442 mAh/g), low voltages (0.12–0.39/0.16–0.62/0.41–0.78 V), and ultra-low migration energy barriers (2.7–38.2/15.0–83.5/44.1–248.7 meV) in Li-/Mg-/Al-ion battery are proved. The performance of M2B2 monolayers in different ion batteries shows clear relationships with both the intrinsic nature of M and the electronegativity of charge carrier. For M2B2 monolayers in same period, the one with heavier M has higher dynamical stability, stronger bonding to charge carriers, and lower reaction voltage. In addition, a specific M2B2 monolayer shows stronger adsorption and slower conduction for the charge carrier with higher electronegativity. This work provides theoretical guidance for developing new MBs anode materials for ion batteries.

Recent Advances on Electrospun Nanofiber Materials for Post-lithium Ion Batteries

Lithium ion batteries (LIBs) have dominated the portable electric market over decades; however, the limited and unevenly distributed lithium resources induce concerns on their future large-scale applications. Increasing efforts have been endeavored on exploring post-Li ion batteries, such as Na-ion, K-ion, Al-ion and Mg-ion batteries, due to the high abundance of the corresponding elements in Earth crust. Manufacturing reliable electrode materials is the key to develop these new battery systems. Facile and scalable electrospinning has been widely utilized in preparing mechanically stable, flexible and conductive nanofiber electrodes as successfully proven in LIBs. In recent years, tremendous efforts have been devoted to electrospinning nanofiber electrodes for post-Li ion batteries and discernible progress in the electrochemical performance has been witnessed. Herein, we aim to review the-state-of-the-art advances made in electrospun nanofiber materials in optimizing post-Li ion battery technology by surveying the correlations among the morphology, the surface chemistry, the structure of electrospun nanofibers, and the post-Li ion batteries performance. Based on intensive investigations and insightful understandings, perspectives to the future design of electrospun nanofiber electrodes are also presented.

A manganese hexacyanoferrate framework with enlarged ion tunnels and two‐species redox reaction for aqueous Al-ion batteries

The recently emerging aqueous Al-ion batteries (AIBs) face the problems of poor rate capability (typically, less than 30% retention with a current density raised to 0.4 A g –1 ) and limited cycle life with rapid capacity degradation (typically, 50% capacity retention after 60 cycles.) The battery failure was typically attributed to the poor stability of the host structure associated with the large polar interaction between the Al ions and host. In this study, a defective manganese hexacyanoferrate (MnFe-PBA) cathode is designed with enlarged ion transportation tunnels and weakened Coulombic interactions with Al ions. Moreover, two reactive metal-sites of MnFe-PBA are both successfully activated, resulting in a large cavity for 1.2 Al ions storage per unit cell. Such structural and active site features contribute to a remarkable rate capability (50.7% capacity retention at 1.0 A g –1 ) and a high specific capacity of 106.3 mAh g −1 . The intrinsic 3-dimensional (3D) framework of MnFe-PBA also delivered superior cycling stability: an ignorable capacity loss after 50 cycles at 0.2 A g −1 and 69.5% retention after 100 cycles at 0.5 A g −1 . Furthermore, nanofibrillated cellulose/polyacrylamide hydrogel electrolytes were applied and successfully prolonged the cycling life to 200 cycles, and the constructed flexible quasi-state Al//MnFe-PBA batteries displayed stable output under various deformations. • Expanded channels offered by Fe(CN)6 vacancies. • Two active metal-ion sites engaged in Al ion storage. • Remarkable rate capability.

Front Cover: Exploring Aluminum‐Ion Insertion into Magnesium‐Doped Manjiroite (MnO2) Nanorods in Aqueous Solution (ChemElectroChem 6/2021)

The Front Cover shows magnesium-doped MnO2 nanorods that are used as an electrode material capable of intercalating/de-intercalating aluminum ions. The open tunnel structure of the nanomaterial as well as the presence of dopant magnesium cations facilitates this process, opening up the possibility of using this material as an electrode in aqueous Al-ion batteries or supercapatteries. More information can be found in the Article by J. Joseph et al.

Metal-ion batteries for electric vehicles: current state of the technology, issues and future perspectives.

The batteries based on metals-ions have the potential to meet the future needs of electric vehicle (EV) applications. This article reviews the key technological developments and scientific challenges of a broad range of Li-ion, Mg-ion and Al-ion batteries for electric vehicles. The fundamental configurations and corresponding reaction mechanisms of metal-ion strategies are tangibly discussed in this review article. After a brief revision of the fundamentals, the performance is analysed among Li-ion, Mg-ion and Al-ion battery technologies. The key parameters for the present compilation are the abundance, the volumetric capacity, the gravimetric capacity, the cycling life, cost and safety. Further, it summarizes the recycling methodologies, strengths and limitations of these batteries. Finally, future directions of all these batteries are highlighted and discussed.

Rechargeable Al-ion batteries

Aluminum (Al) is the most abundant metal element in earth crust, together with low cost and high safety. Al-ion batteries (AIBs) have been regarded as potential alternatives to lithium-ion batteries (LIBs) in large scale applications and attracted much attention in current days. In this review, recent developments of AIBs including the electrolyte exploration, electrode design and Al protection are summarized. Both aqueous and non-aqueous electrolytes exhibit important benefits for AIBs, especially ionic liquid electrolytes with high stripping/plating efficiency, which are preferentially discussed here. Furthermore, we highlight the design principles and electrochemical mechanism for carbons, metal compounds as well as new-type positive electrode materials for high-performance AIBs. Besides, we focus on the negative electrode protection with suitable coating layers to reduce dendrite formation and improve electrochemical activation of Al negative electrodes. The accessible characterization techniques that promote the development of AIBs are discussed. Finally, prospects and outlooks of AIBs towards theoretical investigations and practical applications are provided.