MXene‐Based Anode‐Free Magnesium Metal Battery

Abstract

Rechargeable magnesium batteries (RMBs) are promising next‐generation low‐cost and high‐energy devices. Among all RMBs, anode‐free magnesium metal batteries that use in situ magnesium‐plated current collectors as negative electrodes can afford optimal energy densities. However, anode‐free magnesium metal batteries have remained elusive so far, as their practical application is plagued by low Mg plating/stripping efficiency due to nonuniform Mg deposition on conventional anode current collectors. Herein, for the first time, an anode‐free Mg‐metal battery is developed by employing a 3D MXene (Ti3C2Tx) film with horizontal Mg electrodeposition. The magnesiophilic oxygen and reactive fluorine terminations in MXene enable an enriched local magnesium‐ion concentration and a durable magnesium fluoride‐rich solid electrolyte interphase on the Ti3C2Tx film surface. Meanwhile, Ti3C2Tx MXene exhibits a high lattice geometrical fit with Mg (≈96%) to guide the horizontal electrodeposition of Mg. Consequently, the developed Ti3C2Tx film achieves reversible Mg plating/stripping with high Coulombic efficiencies (>99.4%) at high‐current‐density (5.0 mA cm−2) and high‐Mg‐utilization (50%) conditions. When this Ti3C2Tx film is coupled with a pre‐magnesized Mo6S8 cathode, the anode‐free Mg‐metal full‐cell prototype exhibits a volumetric energy density five times higher than its standard Mg‐metal counterpart. This work provides insights into the rational design of anode current collectors to guide horizontal Mg electrodeposition for anode‐free Mg metal batteries.

Chloride-Free Electrolyte Based on Tetrabutylammonium Triflate Additive for Extended Anodic Stability in Magnesium Batteries

“…Meanwhile, the anodes cycled in the other two electrolytes show relatively lesser surface oxidation and possess a higher amount of Mg­(OH) 2 , which usually suppress electrolyte degradation into the bulk anode . The F 1s spectra confirmed the presence of MgF 2 (685.78 eV) and CF 3 –SO 3 – (689.35 eV) in all three systems. ,, Similarly, the S 2p spectrum confirms the presence of MgS (162.17 eV) and CF 3 –SO 3 – (169.16 eV). , Both groups arise from the decomposition of the OTf – ions. The flat N 1s spectra in all of the electrolyte systems confirm the high reductive stability of TBA + ions against Mg metal.…”

“…38 The F 1s spectra confirmed the presence of MgF 2 (685.78 eV) and CF 3 −SO 3 − (689.35 eV) in all three systems. 42,71,72 Similarly, the S 2p spectrum confirms the presence of MgS (162.17 eV) and CF 3 −SO 3 − (169.16 eV). 18,39 Both groups arise from the decomposition of the OTf − ions.…”

Inhibition of Zinc Dendrite Growth by WC-Cellulose Separators for High-Performance Zinc-Ion Batteries

“…1−4 Thus, AZIBs have been considered as one of the most promising candidates for highdensity energy-storage systems in the application of electric vehicles, portable electronics, and large-scale energy-storage grids. 5,6 Nevertheless, several formidable challenges, including uncontrollable Zn dendrite growth and water-induced side reaction, leading to the low Coulombic efficiency and unsatisfactory working life, retard the commercialization of AZIBs. 7,8 The continuous growth of Zn dendrites on the Zn anode during cyclical Zn deposition/desolution can impale the separator and thus result in the short-circuit and failure of batteries.…”

“…The explosive growth of rechargeable aqueous zinc-ion batteries (AZIBs) in scientific research is ascribed to the advantages of low-cost, high safety, environmental friendliness, rich inventories of Zn metal, and high theoretical capacity (820 mA h·g –1 and 5855 mA h·cm –3 ). − Thus, AZIBs have been considered as one of the most promising candidates for high-density energy-storage systems in the application of electric vehicles, portable electronics, and large-scale energy-storage grids. , Nevertheless, several formidable challenges, including uncontrollable Zn dendrite growth and water-induced side reaction, leading to the low Coulombic efficiency and unsatisfactory working life, retard the commercialization of AZIBs. , The continuous growth of Zn dendrites on the Zn anode during cyclical Zn deposition/desolution can impale the separator and thus result in the short-circuit and failure of batteries. Besides, owing to the high reduction activity, the Zn metal anode can easily react with the water molecules in aqueous electrolyte, leading to the hydrogen evolution reaction (HER) and surface microcorrosion.…”

MXene-modified electrodes and electrolytes in dye-sensitized solar cells

“…MXenes are special structural and electrical two-dimensional (2D) transition metal carbides, nitrides, or carbonitrides. 13–35 They are created by carefully etching layers of MAX phases, where MAX stands for carbon or nitrogen, M for an early transition metal, and A for a group 13 or 14 element. 36,37 MXenes are appealing for various energy storage and conversion applications, including DSSCs, due to their high specific surface area, electrical conductivity, and tunable surface chemistry.…”