Rechargeable magnesium batteries (RMBs) are promising candidates to replace currently commercialized lithium‐ion batteries (LIBs) in large‐scale energy storage applications owing to their merits of ...abundant resources, low cost, high theoretical volumetric capacity, etc. However, the development of RMBs is still facing great challenges including the incompatibility of the electrolyte and the lack of suitable cathode materials with high reversible capacity and fast kinetics of Mg2+. While tremendous efforts have been made to explore compatible electrolytes and appropriate electrode materials, the rational design of unconventional Mg‐based battery systems is another effective strategy for achieving high electrochemical performance. This review specifically discusses the recent research progress of various Mg‐based battery systems. First, the optimization of electrolyte and electrode materials for conventional RMBs is briefly discussed. Furthermore, various Mg‐based battery systems, including Mg‐chalcogen (S, Se, Te) batteries, Mg‐halogen (Br2, I2) batteries, hybrid‐ion batteries, and Mg‐based dual‐ion batteries are systematically summarized. This review aims to provide a comprehensive understanding of different Mg‐based battery systems, which can inspire latecomers to explore new strategies for the development of high‐performance and practically available RMBs.
This review specifically presents current progress on recently developed rechargeable magnesium batteries, including Mg‐chalcogen batteries, Mg‐halogen batteries, hybrid ion batteries, and dual‐ion batteries. Additionally, challenges and potential solutions for these battery systems are proposed. This review aims to show new strategies for the development of high‐performance and practically available magnesium batteries.
•CEI layer of S@pPAN cathode in Mg-S batteries was firstly investigated.•APC-based nucleophilic electrolyte was used as the electrolyte of Mg-S batteries.•Battery performance is enhanced using ...MBA-based non-nucleophilic electrolyte.•This work spark Mg-S batteries with low cost cathode materials and electrolytes.
Magnesium-sulfur (Mg-S) batteries are an alternative electrochemical energy-storage system with higher safety as well as large theoretical volumetric energy density than lithium-sulfur (Li-S) batteries. Herein, we further research sulfurized-pyrolyzed polyacrylonitrile (S@pPAN) composite containing 47.3 wt% sulfur as cathode of Mg-S batteries with nucleophilic (PhMgCl)2-AlCl3 + LiCl/THF electrolyte. Except a significant restraint of the reaction between the nucleophilic electrolyte and the electrophilic sulfur, polysulfide dissolution and shuttle are effectively suppressed. Electrochemical performance is further enhanced using MBA-(MgCl2)2-(AlCl3)2 + LiCl/THF non-nucleophilic electrolyte with 677.9 mAh g−1 specific capacity and 75.9% cycling stability after 85 cycles at 0.1C. More effective CEI layers formed on the cathode with a lower electrode/electrolyte internal resistance play a key effect on the enhanced electrochemical performance. This work will attract extensive study on Mg-S batteries containing easily prepared electrolytes with a combination of S@pPAN cathode.
Magnesium–sulfur (Mg-S) batteries are emerging as a promising alternative to lithium-ion batteries, due to their high energy density and low cost. Unfortunately, current Mg-S batteries typically ...suffer from the shuttle effect that originates from the dissolution of magnesium polysulfide intermediates, leading to several issues such as rapid capacity fading, large overcharge, severe self-discharge, and potential safety concern. To address these issues, here we harness a copper phosphide (Cu3P) modified separator to realize the adsorption of magnesium polysulfides and catalyzation of the conversion reaction of S and Mg2+ toward stable cycling of Mg-S cells. The bifunctional layer with Cu3P confined in a carbon matrix is coated on a commercial polypropylene membrane to form a porous membrane with high electrolyte wettability and good thermal stability. Density functional theory (DFT) calculations, polysulfide permeability tests, and post-mortem analysis reveal that the catalytic layer can adsorb polysulfides, effectively restraining the shuttle effect and facilitating the reversibility of the Mg-S cells. As a result, the Mg-S cells can achieve a high specific capacity, fast rates (449 mAh g–1 at 0.1 C and 249 mAh g–1 at 1.0 C), and a long cycle life (up to 500 cycles at 0.5 C) and operate even at elevated temperatures.
Mg batteries have the advantages of resource abundance, high volumetric energy density, and dendrite‐free plating/stripping of Mg anodes. However the injection of highly polar Mg2+ cannot maintain ...the structural integrity of intercalation‐type cathodes even for open framework prototypes. The lack of high‐voltage electrolytes and sluggish Mg2+ diffusion in lattices or through interfaces also limit the energy density of Mg batteries. Mg–S system based on moderate‐voltage conversion electrochemistry appears to be a promising solution to high‐energy Mg batteries. However, it still suffers from poor capacity and cycling performances so far. Here, a ZIF‐67 derivative carbon framework codoped by N and Co atoms is proposed as effective S host for highly reversible Mg–S batteries even under high rates. The discharge capacity is as high as ≈600 mA h g−1 at 1 C during the first cycle, and it is still preserved at ≈400 mA h g−1 after at least 200 cycles. Under a much higher rate of 5 C, a capacity of 300–400 mA h g−1 is still achievable. Such a superior performance is unprecedented among Mg–S systems and benefits from multiple factors, including heterogeneous doping, Li‐salt and Cl− addition, charge mode, and cut‐off capacity, as well as separator decoration, which enable the mitigation of electrode passivation and polysulfide loss.
A ZIF‐67 derivative carbon framework codoped by N and Co atoms is proposed as an effective S host for highly reversible Mg–S batteries even under high rate up to 5C. The discharge capacity is preserved at 450 mA h g−1 after 250 cycles for 0.1C and 400 mA h g−1 after 200 cycles for 1C. Such a superior performance also benefits from Li‐salt and Cl− addition, charge mode, capacity cut‐off, and separator decoration.
The main challenges faced by magnesium-sulfur (Mg–S) batteries are the polysulfide shuttle effect and slow kinetics of S cathode, causing the severe self-discharge behavior and rapid capacity decay. ...Herein, we elaborately design a MoO2-loaded activated carbon cloth (denoted as MoO2@ACC) functional interlayer to realize high-performance Mg–S batteries. The ACC possesses a remarkable adsorption effect, which can effectively mitigate the polysulfide shuttle effect and enable the Mg–S batteries with a high voltage plateau. Besides, the MoO2 can observably reduce the polarization during charge/discharge process attributed by the fast reaction kinetics due to the catalytic effect. The Mg–S battery with this MoO2@ACC interlayer achieves a high energy density and good capacity retention (80.3 %) after 100 cycles (0.5 C) and effectively mitigates the Mg–S battery's self-discharge as well. This work illustrates the significant role of the interlayer with both adsorption and catalytic functions to boost the usability of the Mg–S batteries.
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•The MoO2@ACC interlayer is prepared by a simple method.•The shuttle effect of the magnesium-sulfur battery is effectively blocked.•The kinetics of the magnesium-sulfur battery is significantly improved.•The magnesium-sulfur battery exhibits a high voltage plateau and high capacity retention of 80.3% at 0.5 C.
Non‐nucleophilic electrolytes that can reversibly plate/strip Mg are essential for realizing high‐performance rechargeable Mg/S batteries. In contrast to organometallic electrolytes, all‐inorganic ...electrolytes based on MgCl2‐AlCl3 complexes are more cost‐effective and hold better stability to air and moisture. A recently developed electrolyte that contains tetrahydrofuran solvated divalent Mg cation, Mg·6THFAlCl42, has exhibited decent compatibility with the sulfur cathode. However, it suffers a large overpotential and short cycle life, which hinders its applications in Mg/S batteries. Here, an efficient plating/stripping of Mg is realized successfully by using LiCl to dissolve MgCl2 from the electrolyte/electrode interface. As a result, the overpotential of Mg plating/stripping is remarkably reduced to 140/140 mV at a current density of 500 µA cm−2. Both experiments and density functional theory (DFT) calculations reveal that the LiCl‐assisted solubilization of MgCl2 facilitates the exposure of fresh surface on the Mg anode. Utilizing such an LiCl‐activation strategy, Mg/S full batteries with a significantly extended cycle life of over 500 cycles, as well as coulombic efficiency close to 100%, are achieved successfully. This work demonstrates the role of LiCl‐assisted interface activation on extending the cycle‐life Mg/S batteries with all‐inorganic electrolytes.
The electrolyte–electrode interface of an Mg anode could be passivated by the formation of low‐solubility species such as MgCl2. Here, it is found that an LiCl additive could effectively boost the interfacial property by forming soluble intermediate species such as Mg2(µ‐Cl)3·6THF+ and LiCl2·2THF−, which is critical to sustain a fresh Mg surface for Mg/S batteries with long cycle life.
Rechargeable magnesium batteries (RMBs) are considered as one of the most promising candidates for next‐generation batteries. However, the popularization of RMBs is seriously plagued due to the lack ...of suitable non‐nucleophilic electrolytes and the passivation of Mg anode. Herein, a novel non‐nucleophilic electrolyte is developed by introducing (s)‐1‐methoxy‐2‐propylamine (M4) into themagnesium aluminum chloride complex (MACC)‐like electrolyte. The as‐synthesizes Mg(AlCl4)2‐IL‐DME‐M4 electrolyte enables robust reversible cycling of Mg plating/stripping with low overpotential, high anodic stability, and ionic conductivity (8.56 mS cm−1). These features should be mainly attributed to the in situ formation of an MgF2 containing Mg2+‐conducting interphase, which dramatically suppresses the passivation and parasitic reaction of Mg anode with electrolyte. Remarkably, the Mg/S batteries assemble with as‐synthesize electrolyte and a new type MoS2@CMK/S cathode deliver unprecedented electrochemical performance. Specifically, the Mg/S battery exhibited the highest reversible capacity up to 1210 mAh g−1 at 0.1 C, excellent rate capability and satisfactory long‐term cycling stability with a reversible capacity of 370 mAh g−1 (coulombic efficiency of ≈100%) at 1.0 C for 600 cycles. The study findings provide a novel strategy and inspiration for designing efficient non‐nucleophilic Mg electrolyte and suitable sulfur‐host materials for practical Mg/S battery applications.
This work is developed an advanced non‐nucleophilic Mg(AlCl4)2‐IL‐DME‐M4 electrolyte and suitable MoS2@CMK/S cathode. Due to the in situ formation of advantageous MgF2 containing SEI at Mg/electrolyte interface, the assembled Mg/S batteries are delivered the highest capacity of 1210 mAh g‐1 at 0.1 C and exhibited excellent long‐term cycling stability with reversible capacity of 370 mAh g‐1 at 1.0 C for 600 cycles.
Magnesium–sulfur batteries are elusive candidates for the post‐lithium‐ion battery. Their critical challenge for commercialization is rapid capacity fading due to polysulfide shuttle dissolution and ...slow kinetics during cycling. Insight into the free volumes, morphology, and structural evolution of the sulfur cathode in an Mg/S battery results in a deep understanding of the electrochemical reaction mechanism to further engineer an efficient electrode. In this work, a sulfur cathode with silicon carbide and graphene‐based material S_SiC_GNP is designed and characterized. The full cell based on the Mg anode and S_SiC cathode achieves a high initial discharge capacity of ≈600 mAh g−1 with short cycle life. Positron annihilation spectroscopy (PAL), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS) combined with a scanning electron microscope are used to investigate defect states, free volume interconnectivity/morphology, and structure evolution of sulfur electrode at different electrochemical states. The results show growth in the free volumes and Mg2+ content upon discharge and shrinking upon recharge, while sulfur content is deficient upon demagnesiation. This work provides deep insight and an effective strategy helping to engineer an efficient cathodic material.
Herein, a crucial issue associated with magnesium–sulfur batteries is addressed using positron annihilation spectroscopy: the complex interplay between the insertion/extraction of Mg2+ ion within the framework of the sulfur cathode and the evolution of the free volume voids at different electrochemical states. The results give a deep understanding of the electrochemical reaction mechanism to engineer an efficient electrode further.
Magnesium (Mg) batteries have attracted growing attention because of their low cost and high volumetric capacity. Mg/S batteries are of particular interest because of the high capacities of Mg and ...sulfur, which cooperatively enable high energy densities. However, the shuttling polysulfides during the S0/S2– conversion impair the cathode stability and corrode the Mg anode. This work reports the in situ sulfurization of carbon-confined cobalt in a mesoporous matrix (MesoCo@C) through sulfur melt impregnation and its effectiveness in uplifting the cathode stability and alleviating the Mg anode corrosion (i.e., formation of magnesium sulfides/sulfates). The CoS x species play important roles in binding with polysulfides and regulating the notorious polysulfide shuttle. Both the carbon matrix and the preserved cobalt are excellent electron conductors and allow fast charge transfer to the CoS x species, which become the active sites that facilitate the interaction with magnesium polysulfides and improve the cathode kinetics. These combined effects collectively give rise to the stable capacity of 280 mAh/g at 0.2 C (1 C = 1675 mA/g) for at least 400 cycles.
