Unlocking the Power of Magnesium Batteries: Synergistic Effect of InSb-C Composites to Achieve Superior Electrochemical Performance.

Pure magnesium anode used in rechargeable magnesium batteries (RMB) exhibits high theoretical capacity but has been challenged by the passivation issue with conventional electrolytes. Alloy-type anodes have the potential to surpass this issue and have attracted increasing attention. However, the kinetic performance and stabilities of conventional alloy anodes are still constrained. In this study, the InSb-10%C anode is synthesized by a two-step high-energy ball milling process. The InSb-10%C anode exhibits a remarkably high capacity of up to 448 mA h g-1, significantly improved cycle performance (234 mA h g-1 at 100 cycles) and rate performance (168 mA h g-1 at 500 mA g-1). The above-mentioned superior performance of the InSb-10%C anode for RMBs is attributed to the cellular graphitized amorphous carbon composite structure (CGA) which effectively refines the particle size and restricts the volume expansion. Additionally, the reduced surface electron density of InSb combined with the high conductivity resulting from graphitization enhances the Mg2+ diffusion performance. Notably, the InSb-10%C anode demonstrates good compatibility with conventional halogen-free salt ether-based electrolytes in the full battery configuration.

Organic Molecular Intercalation Enabled Anionic Redox Chemistry with Fast Kinetics for High Performance Magnesium Storage.

Rechargeable magnesium-ion batteries possess desirable characteristics in large-scale energy storage applications. However, severe polarization, sluggish kinetics and structural instability caused by high charge density Mg2+ hinder the development of high-performance cathode materials. Herein, the anionic redox chemistry in VS4 is successfully activated by inducing cations reduction and introducing anionic vacancies via polyacrylonitrile (PAN) intercalation. Increased interlayer spacing and structural vacancies can promote the electrolyte ions migration and accelerate the reaction kinetics. Thanks to this "three birds with one stone" strategy, PAN intercalated VS4 exhibits an outstanding electrochemical performance: high discharge specific capacity of 187.2 mAh g-1 at 200 mA g-1 after stabilization and a long lifespan of 5000 cycles at 2 A g-1 are achieved, outperforming other reported VS4-based materials to date for magnesium storage under the APC electrolyte. Theoretical calculations confirm that the intercalated PAN can indeed induce cations reduction and generate anionic vacancies by promoting electron transfer, which can accelerate the electrochemical reaction kinetics and activate the anionic redox chemistry, thus improving the magnesium storage performance. This approach of organic molecular intercalation represents a promising guideline for electrode material design on the development of advanced multivalent-ion batteries.

Catalyzing Desolvation at Cathode-Electrolyte Interface Enabling High-Performance Magnesium-Ion Batteries.

Magnesium ion batteries (MIBs) are expected to be the promising candidates in the post-lithium-ion era with high safety, low cost and almost dendrite-free nature. However, the sluggish diffusion kinetics and strong solvation capability of the strongly polarized Mg2+ are seriously limiting the specific capacity and lifespan of MIBs. In this work, catalytic desolvation is introduced into MIBs for the first time by modifying vanadium pentoxide (V2O5) with molybdenum disulfide quantum dots (MQDs), and it is demonstrated via density function theory (DFT) calculations that MQDs can effectively lower the desolvation energy barrier of Mg2+, and therefore catalyze the dissociation of Mg2+-1,2-Dimethoxyethane (Mg2+-DME) bonds and release free electrolyte cations, finally contributing to a fast diffusion kinetics within the cathode. Meanwhile, the local interlayer expansion can also increase the layer spacing of V2O5 and speed up the magnesiation/demagnesiation kinetics. Benefiting from the structural configuration, MIBs exhibit superb reversible capacity (≈300 mAh g-1 at 50 mA g-1) and unparalleled cycling stability (15 000 cycles at 2 A g-1 with a capacity of ≈70 mAh g-1). This approach based on catalytic reactions to regulate the desolvation behavior of the whole interface provides a new idea and reference for the development of high-performance MIBs.

Individualized prediction of non-sentinel lymph node metastasis in Chinese breast cancer patients with ≥ 3 positive sentinel lymph nodes based on machine-learning algorithms.

BACKGROUND: Axillary lymph node dissection (ALND) is a standard procedure for early-stage breast cancer (BC) patients with three or more positive sentinel lymph nodes (SLNs). However, ALND can lead to significant postoperative complications without always providing additional clinical benefits. This study aims to develop machine-learning (ML) models to predict non-sentinel lymph node (non-SLN) metastasis in Chinese BC patients with three or more positive SLNs, potentially allowing the omission of ALND. METHODS: Data from 2217 BC patients who underwent SLN biopsy at Shantou University Medical College were analyzed, with 634 having positive SLNs. Patients were categorized into those with ≤ 2 positive SLNs and those with ≥ 3 positive SLNs. We applied nine ML algorithms to predict non-SLN metastasis. Model performance was evaluated using ROC curves, precision-recall curves, and calibration curves. Decision Curve Analysis (DCA) assessed the clinical utility of the models. RESULTS: The RF model showed superior predictive performance, achieving an AUC of 0.987 in the training set and 0.828 in the validation set. Key predictive features included size of positive SLNs, tumor size, number of SLNs, and ER status. In external validation, the RF model achieved an AUC of 0.870, demonstrating robust predictive capabilities. CONCLUSION: The developed RF model accurately predicts non-SLN metastasis in BC patients with ≥ 3 positive SLNs, suggesting that ALND might be avoided in selected patients by applying additional axillary radiotherapy. This approach could reduce the incidence of postoperative complications and improve patient quality of life. Further validation in prospective clinical trials is warranted.

First-Principles Calculations of TiB4 and TiB5 as Anodes with High Capacity for Na-Ion Batteries.

The electrochemical properties of TiB4 and TiB5 monolayers in Na-ion batteries (NIBs) were studied by using the first-principles calculation method based on density functional theory. The TiB4/TiB5 monolayer showed excellent Na storage capacity, capable of adsorbing two layers of Na with theoretical capacities of 1176.77 and 1052.05 mA g-1, respectively. The average operating voltages of the TiB4 and TiB5 monolayers are 0.073 and 0.042 eV, respectively, indicating that they can be used as anode materials for NIBs. More interestingly, the exposed B surface not only brings a high theoretical capacity but also provides a relatively small diffusion barrier of 0.16 (for TiB4) and 0.33 eV (for TiB5), enhancing their rate capability in NIBs.

Theoretical insights into the intercalation mechanism of Li, Na, and Mg ions in a metallic BN/VS2 heterostructure.

Layered VS2 has been widely used as a battery anode material owing to its large specific surface area and controllable ion-transport channel. However, its semiconductor properties and poor cycling stability seriously limit its further applications. Herein, a two-dimensional BN/VS2 heterostructure (BVH) was constructed as an anode material for rechargeable metal-ion batteries (RMIBs). Demonstrated using first principles calculations, BVH exhibits a metallic property due to lattice stress between monolayer BN and VS2. BVH displays low ion diffusion energy barriers (0.13, 0.43, and 0.56 eV) and high theoretical capacities (447, 553.5, and 340.7 mA h g-1) for Li+, Na+, and Mg2+ storage. In BVH, the VS2 layer as the main redox center supports charge transfer, while the inactive BN layer enables high structural stability. This synergistic effect is expected to simultaneously achieve a high rate, high capacity, and long life. This design provides an important insight into developing new anode materials for RMIBs.

Universal N2O Reaction Gas To Remove Spectral Interferences of Nonmetallic Impurity Elements by Inductively Coupled Plasma Tandem Mass Spectrometry Analysis of High-Purity Magnesium Alloys.

Using N2O as a universal reaction gas, a new strategy was proposed for the highly sensitive interference-free simultaneous determination of nonmetallic impurity elements in high-purity magnesium (Mg) alloys by ICP-MS/MS. In the MS/MS mode, through O-atom and N-atom transfer reactions, 28Si+ and 31P+ were converted to the oxide ions 28Si16O2+ and 31P16O+, respectively, while 32S+ and 35Cl+ were converted to the nitride ions 32S14N+ and 14N35Cl+, respectively. The ion pairs formed via the 28Si+ → 28Si16O2+, 31P+ → 31P16O+, 32S+ → 32S14N+, and 35Cl+ → 14N35Cl+ reactions by the mass shift method could eliminate spectral interferences. Compared with the O2 and H2 reaction modes, the present approach delivered much higher sensitivity and lower limit of detection (LOD) of the analytes. The accuracy of the developed method was evaluated via standard addition method and comparative analysis by sector field ICP-MS (SF-ICP-MS). The study indicates that in the MS/MS mode, use of N2O as reaction gas can provide interference-free conditions and sufficiently low LODs for analytes. The LODs of Si, P, S, and Cl could reach down to 17.2, 4.43, 10.8, and 31.9 ng L-1, respectively, and the recoveries were in the range of 94.0-106%. The determination results of the analytes were consistent with those obtained by SF-ICP-MS. This study presents a systematic method for the precise and accurate quantification of Si, P, S, and Cl in high-purity Mg alloys by ICP-MS/MS. The developed method provides valuable reference that can be expanded and applied to other fields.

Rationally Integrating 2D Confinement and High Sodiophilicity toward SnO2 /Ti3 C2 Tx Composites for High-Performance Sodium-Metal Anodes.

The metallic sodium (Na) is characterized by high theoretical specific capacity, low electrode potential and abundant resources, and its advantages manifests itself as a promising candidate anode of sodium metal batteries (SMBs). However, the vaporization during the plating/stripping or uncontrolled growth of sodium dendrites in sodium metal anodes (SMAs) has posed major challenges to its practical applications. To address this issue, here, the SnO2 /Ti3 C2 Tx composite is rationally fabricated, in which sodiophilic SnO2 nanoparticles are in situ dispersed on the 2D Ti3 C2 Tx , providing the acceptor sites of Na+  that can control vaporization and dendrites. The SnO2 /Ti3 C2 Tx composite anode exhibits smooth and homogeneous morphology after Na-metal deposition cycles, stable Coulombic efficiency (CE) of half cells, long stable cycles of symmetric cells due to highly sodiophilic sites, and confinement effect. In addition, the full cells assembled with Na0.6 MnO2 also show excellent rate performance and cycling performance. These discoveries demonstrate the effectiveness of the acceptor sites and the confinement effect provided by the SnO2 /Ti3 C2 Tx composite, and thus provide an additional degree of freedom for designing SMBs.

A two-dimensional VO2/VS2 heterostructure as a promising cathode material for rechargeable Mg batteries: a first principles study.

Rechargeable magnesium batteries (RMBs) are considered as highly promising energy storage systems. However, the lack of cathode materials with fast Mg2+ diffusion kinetics and high energy density severely hinders the development of RMBs. Herein, a two-dimensional (2D) VO2/VS2 heterostructure as a RMB cathode material is proposed by introducing an O-V-O layer in VS2 to improve the discharge voltage and specific capacity while keeping the fast Mg2+ diffusion kinetics. Based on first principle calculations, the geometric structures, electronic characteristics of the VO2/VS2 heterostructure, and the adsorption properties and diffusion behaviors of Mg2+ in VO2/VS2 are systematically studied. The metallic properties of VO2/VS2 and a relatively low diffusion barrier of Mg2+ (0.6 eV) in VO2/VS2 enable a large potential in delivering high rate performance in actual RMBs. Compared with traditional VS2 materials (1.25 V), the average discharge platform of VO2/VS2 could be increased to 1.7 V. The theoretical capacities of the layered VS2 and VO2/VS2 are calculated as 233 and 301 mA h g-1, respectively. Thus, the VO2/VS2 heterostructure exhibits a high theoretical energy density of 511.7 W h kg-1, significantly surpassing that of VS2 (291.3 W h kg-1). This work provides important guidance for designing high-energy and high-rate 2D heterostructure cathode materials for RMBs and other multivalent ion batteries.

N2O as a Universal Reaction Gas to Overcome Spectral Interference in Determining Metal Impurities in Mg(TFSI)2 Electrolytes for Rechargeable Magnesium Batteries by Inductively Coupled Plasma Tandem Mass Spectrometry.

A new strategy for the determination of metal impurities in magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) electrolytes for rechargeable magnesium batteries using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was proposed. Mg(TFSI)2 was dissolved in 1,2-dimethoxyethane (DME), and 13 metal impurity elements were directly determined. Since N2 has a lower O atom affinity (1.6 eV) than the O atom (5.2 eV), N2O was a more effective O atom transfer gas than O2. In the MS/MS mode, N2O was selected as the reaction gas, and high sensitivities and low limits of detection (LODs) of analytes were obtained by mass shift methods. The accuracy of proposed analytical methods was assessed by the spike recovery experiments and comparative analyses using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). LODs were in the range of 0.18-26.6 ng kg-1, the recoveries were 92.5%-107%, and the relative standard deviation (RSD) was 2.0%-5.3%. No significant difference was observed between the ICP-MS/MS and SF-ICP-MS results at a 95% confidence level. The measurement realized the rapid determination of 13 metal impurity elements in Mg(TFSI)2 using N2O as a reaction gas with high sensitivity, accuracy, and precision. The method was applied for the analysis of Mg(TFSI)2 products with satisfactory results.

Switchable and Strain-Releasable Mg-Ion Diffusion Nanohighway Enables High-Capacity and Long-Life Pyrovanadate Cathode.

Rechargeable magnesium batteries (RMBs) suffer from low capacity and poor cyclability of cathode materials, which is due to the sluggish Mg2+ diffusion kinetics and large lattice strain. Here, a layer-interweaving mechanism in lamellar cathode to simultaneously facilitate Mg2+ diffusion and release Mg2+ -insertion strain is reported. In the Cu3 V2 O7 (OH)2 ·2H2 O (CVOH) cathode, Mg2+ diffusion highways are generated by the vertical interweaving of CVOH layers and V6 O13 layers that nucleate in CVOH during discharging, which are switchable by Mg2+ insertion/extraction. These highways enhance the Mg2+ diffusion coefficient by three orders of magnitude and release 50% Mg2+ -insertion strain. This enables CVOH to exhibit a high capacity of 262 mAh g-1 at high current density of 250 mA g-1 in aqua, and extremely low capacity loss of 0.0004% per cycle in the activated carbon//CVOH cell. This work inspires designing the magnesiation phase transformation of electrodes to resolve both kinetic and strain issues for high-performance RMBs.

Prognostic implication of novel immune-related signature in breast cancer.

Checkpoint inhibitor therapy has become increasingly important and has been endorsed as a treatment regimen in breast cancer. But benefits were limited to a small proportion of patients. We aimed to develop an improved signature on the basis of immune genes for detection of potential benefit from immunotherapy. Gene expression data of patients with breast cancer initially extracted from The Cancer Genome Atlas were analyzed. Ten genes were selected from the interaction of differentially expressed genes as well as immune-related genes to develop a survival signature. We compared the high-risk and low-risk groups by gene set enrichment analysis, immune infiltration, checkpoint molecule expression and immunophenoscore. Ten genes were extracted from interactions of differentially expressed and immune-related genes. The immune risk score was determined on the basis of the Cox regression coefficient of hub genes and validated with the GSE96058 dataset. Immune cell infiltrates, including CD8 + T cells, plasma cells, follicular helper T cells, CD4 + memory T cells, M1 macrophages, regulatory T cells and resting NK cells, were more highly infiltrated in the high-risk group as compared to the low-risk group. Checkpoint molecules, including CTLA-4, PD-L1, TIM-3, VISTA, ICOS, PD-1, and PD-L2, were expressed at markedly lower levels in the high-risk group as compared to the low-risk group. Immunophenoscores, as a surrogate of response to immune checkpoint therapy, was observed significant lower in the high-risk group. The 10-gene prognostic signature could identify patients' survival and was correlated with the biomarkers of immune checkpoint inhibitor therapy, which may guide precise therapeutic decisions in clinical practice.

H2O-Mg2+ Waltz-Like Shuttle Enables High-Capacity and Ultralong-Life Magnesium-Ion Batteries.

Mg-ion batteries (MIBs) are promising next-generation secondary batteries, but suffer from sluggish Mg2+ migration kinetics and structural collapse of the cathode materials. Here, an H2O-Mg2+ waltz-like shuttle mechanism in the lamellar cathode, which is realized by the coordination, adaptive rotation and flipping, and co-migration of lattice H2O molecules with inserted Mg2+, leading to the fast Mg2+ migration kinetics, is reported; after Mg2+ extraction, the lattice H2O molecules rearrange to stabilize the lamellar structure, eliminating structural collapse of the cathode. Consequently, the demo cathode of Mg0.75V10O24·nH2O (MVOH) exhibits a high capacity of 350 mAh g-1 at a current density of 50 mA g-1 and maintains a capacity of 70 mAh g-1 at 4 A g-1. The full aqueous MIB based on MVOH delivers an ultralong lifespan of 5000 cycles The reported waltz-like shuttle mechanism of lattice H2O provides a novel strategy to develop high-performance cathodes for MIBs as well as other multivalent-ion batteries.

Dual-Defect Engineering Strategy Enables High-Durability Rechargeable Magnesium-Metal Batteries.

Rechargeable magnesium-metal batteries (RMMBs) are promising next-generation secondary batteries; however, their development is inhibited by the low capacity and short cycle lifespan of cathodes. Although various strategies have been devised to enhance the Mg2+ migration kinetics and structural stability of cathodes, they fail to improve electronic conductivity, rendering the cathodes incompatible with magnesium-metal anodes. Herein, we propose a dual-defect engineering strategy, namely, the incorporation of Mg2+ pre-intercalation defect (P-Mgd) and oxygen defect (Od), to simultaneously improve the Mg2+ migration kinetics, structural stability, and electronic conductivity of the cathodes of RMMBs. Using lamellar V2O5·nH2O as a demo cathode material, we prepare a cathode comprising Mg0.07V2O5·1.4H2O nanobelts composited with reduced graphene oxide (MVOH/rGO) with P-Mgd and Od. The Od enlarges interlayer spacing, accelerates Mg2+ migration kinetics, and prevents structural collapse, while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity. Consequently, the MVOH/rGO cathode exhibits a high capacity of 197 mAh g-1, and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g-1, capable of powering a light-emitting diode. The proposed dual-defect engineering strategy provides new insights into developing high-durability, high-capacity cathodes, advancing the practical application of RMMBs, and other new secondary batteries.

Ultra-Stable Sodium-Ion Battery Enabled by All-Solid-State Ferroelectric-Engineered Composite Electrolytes.

Symmetric Na-ion cells using the NASICON-structured electrodes could simplify the manufacturing process, reduce the cost, facilitate the recycling post-process, and thus attractive in the field of large-scale stationary energy storage. However, the long-term cycling performance of such batteries is usually poor. This investigation reveals the unavoidable side reactions between the NASICON-type Na3V2(PO4)3 (NVP) anode and the commercial liquid electrolyte, leading to serious capacity fading in the symmetric NVP//NVP cells. To resolve this issue, an all-solid-state composite electrolyte is used to replace the liquid electrolyte so that to overcome the side reaction and achieve high anode/electrolyte interfacial stability. The ferroelectric engineering could further improve the interfacial ion conduction, effectively reducing the electrode/electrolyte interfacial resistances. The NVP//NVP cell using the ferroelectric-engineered composite electrolyte can achieve a capacity retention of 86.4% after 650 cycles. Furthermore, the electrolyte can also be used to match the Prussian-blue cathode NaxFeyFe(CN)6-z·nH2O (NFFCN). Outstanding long-term cycling stability has been obtained in the all-solid-state NVP//NFFCN cell over 9000 cycles at a current density of 500 mA g-1, with a fading rate as low as 0.005% per cycle.

A Novel Asymmetric Diffusion Path for Superior Ion Dynamic in High-Voltage Mg-Based Hybrid Batteries.

Magnesium-based batteries have garnered significant attention due to their high energy density, excellent intrinsic safety, and low cost. However, the application process has been hindered by the high Mg2+ ions diffusion barrier in solid-state structures and solid-liquid interphase. To address this issue, a hybrid battery technology based on Mg anode and Fe-based Prussian Blue Analogue cathode doped with functional transition metal ions and N═O bonds is proposed. Combined multiscale experimental characterizations with theoretical calculations, the subtle lattice distortion can create an asymmetric diffusion path for the active ions, which enables reversible extraction with significantly reduced diffusion barriers achieved by synergistic doping. The optimized cathode exhibits a working potential of 2.3 V and an initial discharge capacity of 152 mAh g-1 at 50 mA g-1. With the preferred electrolyte combined with equivalent concentration [Mg2(µ-Cl)2(DME)4][AlCl4]2 and NaTFSI salt solution, the hybrid system demonstrates superior cycling performance over 200 cycles at a high current density of 200 mA g-1, maintaining ≈100% coulombic efficiency with superior ion dynamic. The findings are expected to be marked an important step in the further application of high-voltage cathodes for Mg-based hybrid batteries.

Binary Mg-1†at%Gd alloy anode for high-performance rechargeable magnesium batteries.

Rechargeable magnesium batteries (RMBs) become a highly promising candidate for the large-scale energy storage system by right of the high volumetric capacity, intrinsic safety and abundant resources of Mg anode. However, the uneven Mg stripping and large overpotential will cause a severe pitting perforation and the followed failure of Mg anode. Herein, we proposed a high-performance binary Mg-1 at% Gd alloy anode prepared by the melting and hot extrusion. The introduction of 1 at% Gd element can effectively reduce the Mg2+ diffusion energy barrier (0.34 eV) on alloy surface and induces the formation of a robust and low-resistance electrolyte/anode interphase, thus enabling a uniform and fast Mg plating/stripping. As a result, the Mg-1 at.% Gd anode displays a largely enhanced life of 220 h and a low overpotential of 213 mV at a high current density of 5.0 mA cm-2 with 2.5 mAh cm-2 . Moreover, the assembled Mg-1 at.% Gd//Mo6 S8 full cell delivers a high rate performance (73.5 mAh g-1 at 5 C) and ultralong cycling stability of 8000 cycles at 5 C. This work brings new insights to design the new-type and practical Mg alloy anodes for commercial RMBs.

Realization of Mg2+ intercalation in a thermodynamically stable layer-structured oxide.

Magnesium batteries have emerged as one of the considerable choices for next-generation batteries. Oxide compounds have attracted great attention as cathodes for magnesium batteries because of their high output voltages and ease of synthesis. However, a majority of the reported results are based on metastable nanoscale oxide materials. This study puts forward a thermodynamically stable layer-structured oxide K0.5MnO2 with an enlarged lattice spacing as a model cathode material employing optimized electrolytes, enabling Mg2+ intercalation into the K0.5MnO2 framework in a real magnesium battery directly using Mg foil as the anode. First-principles calculations implied that the enlarged layer spacing could decrease the migration energy barrier of Mg2+ in the layered oxide. This work can pave the way to understanding the fundamental intercalation behavior of Mg2+ in magnesium batteries.

Large-Scale Integration of the Ion-Reinforced Phytic Acid Layer Stabilizing Magnesium Metal Anode.

Rechargeable magnesium batteries (RMBs) have garnered significant attention for their potential in large-scale energy storage applications. However, the commercial development of RMBs has been severely hampered by the rapid failure of large-sized Mg metal anodes, especially under fast and deep cycling conditions. Herein, a concept proof involving a large-scale ion-reinforced phytic acid (PA) layer (100 cm × 7.5 cm) with an excellent water-oxygen tolerance, high Mg2+ conductivity, and favorable electrochemical stability is proposed to enable rapid and uniform plating/stripping of Mg metal anode. Guided by even distributions of Mg2+ flux and electric field, the as-prepared large-sized PA-Al@Mg electrode (5.8 cm × 4.5 cm) exhibits no perforation and uniform Mg plating/stripping after cycling. Consequently, an ultralong lifespan (2400 h at 3 mA cm-2 with 1 mAh cm-2) and high current tolerance (300 h at 9 mA cm-2 with 1 mAh cm-2) of the symmetric cell using the PA-Al@Mg anode could be achieved. Notably, the PA-Al@Mg//Mo6S8 full cell demonstrates exceptional stability, operating for 8000 cycles at 5 C with a capacity retention of 99.8%, surpassing that of bare Mg (3000 cycles, 74.7%). Moreover, a large-sized PA-Al@Mg anode successfully contributes to the stable pouch cell (200 and 750 cycles at 0.1 and 1 C), further confirming its significant potential for practical utilization. This work provides valuable theoretical insights and technological support for the practical implementation of RMBs.

High-capacity, fast-charging and long-life magnesium/black phosphorous composite negative electrode for non-aqueous magnesium battery.

Secondary non-aqueous magnesium-based batteries are a promising candidate for post-lithium-ion battery technologies. However, the uneven Mg plating behavior at the negative electrode leads to high overpotential and short cycle life. Here, to circumvent these issues, we report the preparation of a magnesium/black phosphorus (Mg@BP) composite and its use as a negative electrode for non-aqueous magnesium-based batteries. Via in situ and ex situ physicochemical measurements, we demonstrate that Mg ions are initially intercalated in black phosphorus two-dimensional structures, forming chemically stable MgxP intermediates. After the formation of the intermediates, Mg electrodeposition reaction became the predominant. When tested in the asymmetric coin cell configuration, the Mg@BP composite electrode allowed stable stripping/plating performances for 1600 h (800 cycles), a cumulative capacity of 3200 mAh cm-2, and a Coulombic efficiency of 99.98%. Assembly and testing of the Mg@BP | |nano-CuS coin cell enabled a discharge capacity of 398 mAh g-1 and an average cell discharge potential of about 1.15 V at a specific current of 560 mA g-1 with a low decay rate of 0.016% per cycle for 225 cycles at 25 °C.