Rechargeable Magnesium-ion Batteries Research Articles

High-rate aqueous magnesium ion battery enabled by Li/Mg hybrid superconcentrated electrolyte

Rechargeable aqueous magnesium ion batteries (AMIBs) are considered a promising energy storage system due to the relatively high energy density, excellent rate performance and reversibility, and absence of dendrite formation during cycling. However, the high surface charge density of Mg2+ ions results in slow diffusion kinetics, and high voltage leads to excessive electrolyte decomposition at the electrode/aqueous electrolyte interface, thereby limiting the development of high-energy–density MIBs. In this work, we extend the electrochemical stability window of the aqueous electrolyte to 2.1 V by using a hybrid ion superconcentrated electrolyte at concentrations not achievable with Mg2+ electrolytes alone. The AMIB with a water-in-salt (WIS) electrolyte delivers discharge capacities of up to 200.6 and 84.4 mAh g−1, and energy densities of 170.1 and 68.1 Wh Kg−1 at 0.5 and 20 A g−1, respectively, representing excellent rate performance, while retaining 85 % of the specific capacity after 2000 cycles. Additionally, we explore the corresponding electrochemical reaction mechanism, revealing the synergistic effect of Mg2+ and Li+ ions in the charge/discharge process, which supports the excellent electrochemical performance of AMIB.

A novel two-dimensional monolayer MB4(M = Cr, Mo, W) MBenes as a high-performance anode material for Mg-ion batteries

Rechargeable magnesium-ion batteries have garnered with great interest because abundant resources of magnesium and their potential for achieving high energy density. However, the realization of MIBs is hindered by the lack of appropriate electrode materials. In this study, the potential of 2D monolayers of CrB4, MoB4, and WB4 as anode materials for MIBs has been thoroughly studied using DFT calculations. Our preliminary investigations indicate that these monolayers demonstrate structural, mechanical, and thermodynamic stability. The significantly negative adsorption energy plays a vital role in stabilizing the surface adsorption of Mg ions, preventing clustering, and ensuring the stability of MIBs. The maximum TSC values are 3377 mA h g−1,2311 mA h g−1 and 1416 mA h g−1; and relatively low average OCV of 0.27 V,0.28 V and 0.19 V for CrB4, MoB4 and WB4 respectively, which is favoring to attaining high energy-density. The electronic properties revealed that as the Mg ion concentration increased, the electrical conductivity of the materials improved while maintaining their metallic nature, even after adsorption. However, the energy barriers were slightly higher and consistent with those of many common materials used as 2D anodes. Anticipated light shading of CrB4, MoB4, and WB4 was predicted to identify novel anode materials for MIBs.

Monitoring Structural Changes during Electrochemical Cycling of Solid-Solution Spinel Oxide MgCrVO4.

Rechargeable magnesium-ion batteries (MIBs) hold significant promise as an alternative to conventional lithium-ion technology driven by their natural abundance and low-cost, high-energy density, and safety features. Spinel oxides, including MgCrVO4, have emerged as a prospective cathode material for MIBs due to their promising combination of capacity, operating potential, and cation mobility. However, the structural evolution, phase stability, and processes of Mg mobility in MgCrVO4 during electrochemical cycling are poorly understood. In this study, we synthesized a single-phase, solid solution of spinel oxide MgCrVO4 and employed operando X-ray diffraction to couple physical properties with structural changes during cycling. Our results revealed a two-phase reaction mechanism coupled with a solid-solution-like reaction, highlighting the complicated transformation between two distinct phases in the MgCrVO4 lattice during Mg (de)intercalation. Rietveld refinement of the operando data provided valuable insights into the mechanism of the Cr/V-based spinel oxide, shedding light on the transition between the two phases and their roles in Mg-ion (de)intercalation. This study contributes to a deeper understanding of the structural dynamics in multivalent cathode materials and sets the stage for the development of advanced Mg-ion cathodes with enhanced performance and stability.

High-efficiency electrodeposition of magnesium alloy-based anodes for ultra-stable rechargeable magnesium-ion batteries.

Rechargeable magnesium batteries (RMBs) have attracted much attention because of their high theoretical volumetric capacity and high safety. However, the uneven deposition behavior, harmful corrosion reaction and poor stability of magnesium metal anodes have hindered the practical application of RMBs. Herein, we propose a facile alloy electrodeposition method to construct an artificial layer on an Mg anode. Experimental results show that the polarization of the symmetric magnesium alloy-based (Mg-Sn@Mg and Mg-Bi@Mg) cells is significantly reduced (∼0.05 V) at a current density of 0.1 mA cm-2. The symmetric cells using the prepared Mg alloy anodes exhibited lower voltage hysteresis and ultra-stable cycling performance at a higher density of 1.0 mA cm-2 over 700 h. The in situ optical microscopy study clearly demonstrated that the Mg dendrite formation was successfully retarded by the designed Mg-Sn and Mg-Bi alloy artificial protective layer on Mg anodes. The superiority of Mg-Sn@Mg and Mg-Bi@Mg was further confirmed in full cells using Mo6S8 as the cathode. Compared with the Mo6S8//Mg full cell, the Mo6S8//Mg-Sn@Mg and Mo6S8//Mg-Bi@Mg full cells maintained an ultra-stable electrochemical performance even after 5000 cycles. This proof-of-concept provides a novel scope for the artificial coating layers on Mg anodes prepared by alloy electrodeposition and can be extended to other alloy anodes (i.e. Mg-Cu@Mg and so on). This work provides an avenue for the design of practical and high-performance RMBs and beyond.

Improvements in the Electrochemical Performance of Sodium Manganese Oxides by Ti Doping for Aqueous Mg-Ion Batteries.

In recent times, the research on cathode materials for aqueous rechargeable magnesium ion battery has gained significant attention. The focus is on enhancing high-rate performance and cycle stability, which has become the primary research goal. Manganese oxide and its derived Na-Mn-O system have been considered as one of the most promising electrode materials due to its low cost, non-toxicity and stable spatial structure. This work uses hydrothermal method to prepare titanium gradient doped nano sodium manganese oxides, and uses freeze-drying technology to prepare magnesium ion battery cathode materials with high tap density. At the initial current density of 50 mA g-1 , the NMTO-5 material exhibits a high reversible capacity of 231.0 mAh g-1 , even at a current density of 1000 mA g-1 , there is still 122.1 mAh g-1 . It is worth noting that after 180 cycles of charging and discharging at a gradually increasing current density such as 50-1000 mA g-1 , it can still return to the original level after returning to 50 mA g-1 . Excellent electrochemical performance and capacity stability show that NMTO-5 material is a promising electrode material.

A critical review of inorganic cathode materials for rechargeable magnesium ion batteries

Rechargeable magnesium ion batteries (RMIBs) have received growing attention due to their advantages of abundant resources, low price, environmental friendliness, and high volumetric capacities. However, the highly polarized Mg2+ ions tend to interact with cathode materials, resulting in the sluggish diffusion kinetics. Therefore, design and synthesis high-performance cathode materials are crucial to the development of RMIBs. Most organic cathode materials for RMIBs not only face the problems of poor intrinsic conductivity and low density of the active material, but also are easily soluble in organic electrolytes and have complex redox mechanisms. At present, most of the research on cathodes for RMIBs is inorganic materials. In recent years, researchers have devoted great effort to the design of efficient cathode materials for RMIBs and the reported cathode materials mainly include transition metal oxides, transition metal sulfides, transition metal selenides, polyanionic compounds, and so on. In this review, we provide an extensive overview of different types of inorganic cathodes for RMIBs, with emphasis on describing the structural characteristics, the charge storage mechanisms, electrochemical properties and optimization ideas of different types of cathodes, highlighting some common strategies currently used to improve the electrochemical magnesium storage performance of cathodes. The aim of this widely covered review is to present important research works on different types of inorganic materials when used as cathodes for RMIBs, to summarize the challenges they face and the future directions. This is a departure from articles with an in-depth study of a particular branch. We hope to promote more research efforts on RMIBs in the future.

One-step synthesis of Broccoli-like Ni3S4 for Mg-ion batteries with excellent long cycle stability

The Broccoli-like Ni3S4 was successfully synthesized by a simple one-step hydrothermal method and used as cathode material for rechargeable magnesium ion batteries. Broccoli-like Ni3S4 consists of a large number of zero-dimensional nanoparticles, so that the ion and electron transport distances are on the nanoscale in either direction, resulting in the same degree of deformation inside and outside the particles during magnesium storage, and the Ni3S4 itself is a dense stacked crystal structure. These properties provide favorable conditions for the structural stability of Ni3S4. In addition, the rich pore structure of Broccoli-like Ni3S4 shortens the ion transport path and provides abundant reaction sites. Due to the excellent characteristics of Broccoli-like Ni3S4, the capacity retention rate is close to 100 % after 200 cycles at the current density of 100 mA g−1.

Solid polymer electrolyte based on PEO/PVDF/Mg(ClO4)2-[EMIM][ESO4] system for rechargeable magnesium ion batteries

Solid polymer electrolyte based on PEO/PVDF/Mg(ClO4)2-[EMIM][ESO4] system for rechargeable magnesium ion batteries

Studying δ-MnO2/reduced graphene oxide composite cathode in a low-temperature and high-voltage-tolerant hybrid electrolyte for aqueous Mg-ion batteries

Optimization of the aqueous electrolyte concentration is a significant issue in the development of high-performance aqueous rechargeable magnesium ion batteries (MIBs). In this study, a novel magnesium ion-based hybrid electrolyte composed of 2 M magnesium sulfate (MgSO4)/2 M acetate (MgOAc) was designed, and its corresponding physiochemical properties were systemically investigated by simply tuning their molar ratios. Additionally, a δ-MnO2/reduced graphene oxide (rGO) composite cathode material was successfully synthesized and delivered a high specific capacity and excellent rate capability in the optimized hybrid electrolyte. The as-fabricated device based on the δ-MnO2/rGO composite cathode exhibited a high operating voltage of up to 2 V and delivered a maximum energy density of 29.8 Wh kg−1 at the power density of 823 W kg−1. More importantly, the device showed impressive discharge capacity and excellent cycling stability even at the low temperature of −20 °C. In view of the outstanding electrochemical properties of the δ-MnO2/rGO composite cathode in an optimized hybrid electrolyte of MgSO4/MgOAc, it could be regarded as a novel prototype for low-cost aqueous MIBs.

Hierarchical BiOCl flowerlike microspheres via a room-temperature solid-state chemical reaction as a new anode for rechargeable magnesium-ion batteries.

Rechargeable magnesium-ion batteries (MIBs) have received much attention in recent years, but their development remains limited due to a lack of anode materials with high capacity and fast diffusion kinetics. Herein, for the first time, hierarchical BiOX (X = Cl, Br, I) flowerlike microspheres composed of interleaved nanosheets are constructed via a simple room-temperature solid-state chemical reaction as the anode for MIBs. Among them, BiOCl flowerlike microspheres deliver good cycling stability (110 mA h g-1 after 100 cycles) and a superior rate capacity (134 mA h g-1 at 500 mA g-1). This is attributed to their unique flowerlike microsphere structure that not only accommodates a volume change to maintain their structural integrity but also shortens the ion-transport path to improve the diffusion rate. Importantly, ex situ tests were carried out to clarify the phase and structure evolution of the BiOCl flowerlike microspheres during cycling. The results show that BiOCl is first transformed to Bi and then alloyed to Mg3Bi2 in the discharging process, and Mg3Bi2 is turned back to Bi in the charging process. Besides, the initial microsphere structure is essentially maintained during the discharging/charging process, indicating the better stability of the structure. The current study demonstrates that the structural design of flowerlike microspheres is an effective strategy to develop promising anode materials for MIBs.

Progress and perspective on rechargeable magnesium-ion batteries

Progress and perspective on rechargeable magnesium-ion batteries

Magnesium Bis(Oxalate)Borate as a Potential Electrolyte for Rechargeable Magnesium Ion Batteries

Magnesium Bis(Oxalate)Borate as a Potential Electrolyte for Rechargeable Magnesium Ion Batteries

Recent Progress in Bi-Based Anodes for Magnesium Ion Batteries.

Rechargeable magnesium ion batteries (MIBs) have attracted increasing interest due to abundant reserves, high theoretical specific capacities and safety. However, the incompatibility between Mg metal and conventional electrolytes, among the most serious challenges, restrains their development. Replacing Mg metal with alloy-type anodes offers an effective strategy to circumvent the surface passivation issue of Mg metal in conventional electrolytes. Among them, Bi has the most potential in Mg storage owing to its unique characteristics. Herein, the advantages/challenges and progress of Bi-based anodes in MIBs are summarized. The theoretical evaluations, battery configurations, electrode designs, electrochemical properties as well as Mg storage mechanisms are summarized and discussed. Moreover, the key issues and some views on the future development of Bi-based anodes in MIBs are provided.

Emerging rechargeable aqueous magnesium ion battery

Recently, aqueous rechargeable batteries have played an essential role in developing renewable energy due to the merits of low cost, high security, and high energy density. Among various aqueous-based batteries, aqueous magnesium ion batteries (AMIBs) have rich reserves and high theoretical specific capacity (3833 mAh cm −3 ). However, for future industrialization, AMIBs still face many scientific issues to be solved, such as the slow diffusion of magnesium ions in the material structure, the desolvation penalty at electrode-electrolyte interfaces, the cost of water-in-salt electrolyte, the low voltage of traditional aqueous electrolyte, etc. And yet a comprehensive summary of the components of AMIBs is lacking in the research community. This review mainly introduces the exploration and development of AMIB systems and related components. We conduct an in-depth study of the cathode materials appropriate for magnesium ion batteries from their crystal structures, focusing primarily on layered structures, spinel structures, tunnel structures, and three-dimensional framework structures. We also investigate the anode materials, ranging from inorganic materials to organic materials, as well as the electrolyte materials (from the traditional electrolyte to water-in-salt electrolyte). Finally, some perspectives on ensuing optimization design for future research efforts in the AMIBs field are summarized.

Rechargeable Magnesium Ion Batteries Based on Nanostructured Tungsten Disulfide Cathodes

Finding effective cathode materials is currently one of the key barriers to the development of magnesium batteries, which offer enticing prospects of larger capacities alongside improved safety relative to Li-ion batteries. Here, we report the hydrothermal synthesis of several types of WS2 nanostructures and their performance as magnesium battery cathodes. The morphology of WS2 materials was controlled through the use of sodium oxalate as a complexing agent and different templating agents, including polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and hexadecyltrimethyl ammonium bromide (CTAB). A high capacity of 142.7 mAh/g was achieved after 100 cycles at a high current density of 500 mA/g for cathodes based on a nanostructured flower-like WS2. A solution consisting of magnesium (II) bis(trifluoromethanesulfonyl)imide (MgTFSI2) and magnesium (II) chloride (MgCl2) in dimethoxyethane (DME) was used as an effective electrolyte, which contributes to favorable Mg2+ mobility. Weaker ionic bonds and van der Waals forces of WS2 compared with other transition metal oxides/sulfides lay the foundation for fast discharge/charge rate. The enhanced surface area of the nanostructured materials plays a key role in enhancing both the capacity and discharge/charge rate.

In-situ synthesis of Bi nanospheres anchored in 3D interconnected cellulose nanocrystal derived carbon aerogel as anode for high-performance Mg-ion batteries

Rechargeable magnesium-ion batteries (MIBs) are considered to be promising electrochemical energy storage systems because of their low-cost and high safety features. However, the absence of suitable anodes severely impeded the development of high-performance MIBs. Herein, a unique Bi nanospheres homogenously anchored in cellulose nanocrystal (CNC) derived carbon aerogel (CNC-CA@Bi-NS) hybrid, was for the first time fabricated as anode for MIBs through ion-induced gelation and in-situ thermal reduction processes. The successfully incorporation of near-monodisperse Bi nanospheres (4–9 nmdiameter) into the interconnected CA matrix could effectively alleviate the volume changes during magnesiation/de-magnesiation alloying reaction, as well as prevent the agglomeration and pulverization of Bi nanospheres. Meanwhile, the N-doped porous matrix not only served as a highly electronic conductive framework but also provided enough space and large surface area for electrolyte storage and penetration, which would facilitate the charge transfer kinetics process. Attractively, the CNC-CA@Bi-NS electrode delivered a remarkable reversible specific capacity of 346 mAh/g at 0.5C (90 % of theoretical capacity) after 100cycles. Furthermore, the CNC-CA@Bi-NS exhibited an excellent rate performance and unprecedented long-term cycling stability with a high coulombic efficiency of ∼ 100 % at 2.0C after 5000cycles. This work provided a new strategy to design and synthesize high-performance Bi-based anode for advanced next-generation MIBs.

First principle study of benzoquinone based microporous conjugated polymers as cathode materials for high-performance magnesium ion batteries

Rechargeable magnesium-ion batteries (MIBs) can fulfill large-scale energy storage needs due to the abundance of Mg but technical challenges due to complexity of its chemistry results uncertainties about their commercialization. We for the first report benzoquinone-based microporous conjugated polymer (BQMCP) as cathode material for MIBs using density functional theory. It is dynamically and thermodynamically stable with a strong affinity for Mg-ions. The Mg ions strongly attaches to the CO group (redox-active sites) than π-bonds of BQMCP. The binding energy demonstrates that the interaction of the 2 Mg-ion system (BE = −47.32 kcal.mol−1) is stronger than the mono-Mg ion system (BE = −39.57 kcal.mol−1). The attachment of first Mg2+ to the BQMCP facilitate the attachment of another Mg ion. The BQMCP shows higher positive redox potential, which decreases with the increase of Mg atoms with the high storage capacity of twelve Mg ions/ BQMCP unit at redox-active sites without any structure distortion. Mg ions successfully entraps in bulk porous stacked BQMCP layers with higher negative binding energy values. The results demonstrates that the BQMCP is a promising cathode material for magnesium ion batteries in future.

Simply Prepared Magnesium Vanadium Oxides as Cathode Materials for Rechargeable Aqueous Magnesium Ion Batteries.

Vanadium-oxide-based materials exist with various vanadium oxidation states having rich chemistry and ability to form layered structures. These properties make them suitable for different applications, including energy conversion and storage. Magnesium vanadium oxide materials obtained using simple preparation route were studied as potential cathodes for rechargeable aqueous magnesium ion batteries. Structural characterization of the synthesized materials was performed using XRD and vibrational spectroscopy techniques (FTIR and Raman spectroscopy). Electrochemical behavior of the materials, observed by cyclic voltammetry, was further explained by BVS calculations. Sluggish Mg2+ ion kinetics in MgV2O6 was shown as a result of poor electronic and ionic wiring. Complex redox behavior of the studied materials is dependent on phase composition and metal ion inserted/deinserted into/from the material. Among the studied magnesium vanadium oxides, the multiphase oxide systems exhibited better Mg2+ insertion/deinsertion performances than the single-phase ones. Carbon addition was found to be an effective dual strategy for enhancing the charge storage behavior of MgV2O6.

A high-performance room-temperature magnesium ion battery with self-healing liquid alloy anode mediated with a bifunctional intermetallic compound

Liquid metals with a self-healing property can address the passivation issue of Mg metal and the huge volume variation problem of solid alloy-type anodes in rechargeable magnesium ion batteries (MIBs). Liquid Ga-based anodes show great potentials in MIBs, however, being operated at room temperature is a great challenge. Herein, a novel strategy is proposed to enhance the room-temperature Mg storage performance of liquid eutectic GaSn (EGaSn) alloy through constructing a bifunctional intermetallic compound (Ag3Ga) layer on the current collector. This Ag3Ga layer could greatly improve the wettability of EGaSn on the substrate in the electrolyte environment. Moreover, operando X-ray diffraction confirms that Ag3Ga could participate the reversible alloying/dealloying reactions during the discharge/charge processes and thus provide an extra capacity. Eventually, the Ag3Ga-mediated EGaSn anode exhibits outstanding electrochemical performance towards Mg storage in both half and full cells at room temperature (∼24 and 21 °C), as benchmarked with state-of-the-art anodes in MIBs. Specially, the MIBs could be stably cycled up to 600 cycles in the half cell configuration, and 100 cycles in the full cell assembly. This work provides useful information on the development of advanced anodes for MIBs.

Off-Planar, Two-Dimensional Polymer Cathode for High-Rate, Durable Rechargeable Magnesium Batteries.

Rechargeable magnesium batteries are of considerable interest due to their high theoretical capacity, and they are projected as good alternates for stationary energy storage and electric vehicles. Sluggish Mg2+ kinetics and scarce availability of suitable cathode materials are major issues hindering the progress of rechargeable magnesium batteries. Herein, a conjugated, off-planar, two-dimensional (2D) polymer is explored for reversible magnesium storage. The polymer cathode reveals high capacity and high cycling stability with high rate capability. Replacing the Mg metal anode with the Mg alloy, AZ31 further enhances the ion storage performance. At a high current density of 2 A g-1, stable capacity is shown for almost 5000 cycles with 99% Coulombic efficiency. A composite of carbon nanotube with the polymer delivers capacity values higher (>1.5 times) than that of a pristine polymer at a current density of 2 A g-1 and shows cycling up to 5 A g-1. Electrokinetic studies reveal a contribution of pseudocapacitive nature, and the mechanism is investigated by ex situ X-ray photoelectron spectroscopy and infrared spectroscopy. The use of 2D polymer electrodes opens up opportunities for developing high-rate, high-capacity, and stable rechargeable magnesium ion batteries.