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Rechargeable Mg ion batteries (MIBs) have aroused great interests, and using alloy-type anodes and conventional electrolytes offers an effective way to develop high energy density Mg battery systems. However, the dealloying-induced nanoporosity evolution of alloy-type anodes during the charging process has received less attention. Herein, using a magnetron-sputtered Mg3Bi2 film as an example, we investigate its electrochemical dealloying and associated structural evolution in an all-phenyl-complex electrolyte by in-situ and ex-situ characterizations. The microstructures and length scales of nanoporous Bi can be facilely regulated by changing electrochemical parameters, and there exists a good linear correlation between the surface diffusivity of Bi and the applied current density/potential scan rate on a logarithm scale. More importantly, the self-supporting nanoporous Bi electrodes deliver satisfactory Mg storage performance and alloy-type anodes show good compatibility with conventional electrolytes. Furthermore, the charging-induced dealloying in MIBs is a general strategy to fabricate nanoporous less noble metals like Sn, Pb, In, Cu, Zn and Al, which shows advantages over chemical dealloying in aqueous solutions. Our findings highlight the significance of nanoporosity evolution of alloy-type anodes during dealloying, and open opportunities for the fabrication of nanoporous reactive metals.

Solid electrolytes with high Mg-ion conductivity are required to develop solid-state Mg-ion batteries. The migration energies of the Mg2+ ions of 5,576 Mg compounds tabulated from the inorganic crystal structure database (ICSD) were evaluated via high-throughput calculations. Among the computational results, we focused on the Mg2+ ion diffusion in Mg0.6Al1.2 Si1.8O6, as this material showed a relatively low migration energy for Mg2+ and was composed solely of ubiquitous elements. Furthermore, first-principles molecular dynamics calculations confirmed a single-phase Mg2+ ion conductor. The bulk material with a single Mg0.6Al1.2Si1.8O6 phase was successfully prepared using the sol-gel method. The relative density of the sample was 81%. AC impedance measurements indicated an electrical conductivity of 1.6 × 10−6 Scm−1 at 500°C. The activation energy was 1.32 eV, which is comparable to that of monoclinic-type Mg0.5Zr2(PO4)3.

Rechargeable Mg ion batteries (MIBs) have aroused great interests, and using alloy-type anodes and conventional electrolytes offers an effective way to develop high energy density Mg battery systems. However, the dealloying-induced nanoporosity evolution of alloy-type anodes during the charging process has received less attention. Herein, using a magnetron-sputtered Mg 3 Bi 2 film as an example, we investigate its electrochemical dealloying and associated structural evolution in an all-phenyl-complex electrolyte by in-situ and ex-situ characterizations. The microstructures and length scales of nanoporous Bi can be facilely regulated by changing electrochemical parameters, and there exists a good linear correlation between the surface diffusivity of Bi and the applied current density/potential scan rate on a logarithm scale. More importantly, the self-supporting nanoporous Bi electrodes deliver satisfactory Mg storage performance and alloy-type anodes show good compatibility with conventional electrolytes. Furthermore, the charging-induced dealloying in MIBs is a general strategy to fabricate nanoporous less noble metals like Sn, Pb, In, Cu, Zn and Al, which shows advantages over chemical dealloying in aqueous solutions. Our findings highlight the significance of nanoporosity evolution of alloy-type anodes during dealloying, and open opportunities for the fabrication of nanoporous reactive metals. [ABSTRACT FROM AUTHOR]

Solid electrolytes with high Mg-ion conductivity are required to develop solid-state Mg-ion batteries. The migration energies of the Mg2+ ions of 5,576 Mg compounds tabulated from the inorganic crystal structure database (ICSD) were evaluated via high-throughput calculations. Among the computational results, we focused on the Mg2+ ion diffusion in Mg0.6Al1.2 Si1.8O6, as this material showed a relatively low migration energy for Mg2+ and was composed solely of ubiquitous elements. Furthermore, first-principles molecular dynamics calculations confirmed a single-phase Mg2+ ion conductor. The bulk material with a single Mg0.6Al1.2Si1.8O6 phase was successfully prepared using the sol-gel method. The relative density of the sample was 81%. AC impedance measurements indicated an electrical conductivity of 1.6 × 10−6 Scm−1 at 500°C. The activation energy was 1.32 eV, which is comparable to that of monoclinic-type Mg0.5Zr2(PO4)3. [ABSTRACT FROM AUTHOR]

Solid electrolytes with high Mg-ion conductivity are required to develop solid-state Mg-ion batteries. The migration energies of the Mg2+ ions of 5,576 Mg compounds tabulated from the inorganic crystal structure database (ICSD) were evaluated via high-throughput calculations. Among the computational results, we focused on the Mg2+ ion diffusion in Mg0.6Al1.2 Si1.8O6, as this material showed a relatively low migration energy for Mg2+ and was composed solely of ubiquitous elements. Furthermore, first-principles molecular dynamics calculations confirmed a single-phase Mg2+ ion conductor. The bulk material with a single Mg0.6Al1.2Si1.8O6 phase was successfully prepared using the sol-gel method. The relative density of the sample was 81%. AC impedance measurements indicated an electrical conductivity of 1.6 × 10−6 Scm−1 at 500°C. The activation energy was 1.32 eV, which is comparable to that of monoclinic-type Mg0.5Zr2(PO4)3. [ABSTRACT FROM AUTHOR]

In this work, the electrochemical properties of micron In–Sn–Bi alloy electrodes for rechargeable magnesium batteries (RMBs) are evaluated. Compared with the low stability pure Bi anode, In–Sn–Bi alloy anodes show high reversible specific capacity and high cycle stability. Among the studied alloys, In 10 Sn 10 Bi 80 electrode shows high reversible specific capacity up to 260 mAh g−1, good rate performance and excellent cycle stability (capacity retention above 98% after 80 cycles). The synergistic effects coming from the multi-phase structure have been clarified. The multi-phase structure resists the volume change and structural collapse and then guarantee the good cycle stability compared with that of pure Bi. Additionally, benefited by the fast kinetics of magnesiation/de-magnesiation of the dispersed Bi-rich phase, the reversibility of magnesiation/de-magnesiation of In and Sn are also realized. The multi-phase & fine-substructure design of the electrode materials is promising for the application in RMBs. [Display omitted] • Ternary In–Sn–Bi anodes were synthesized by simple mechanical ball milling method. • Bi-rich fine-substructure designed alloy provides good diffusion kinetics of Mg2+. • Multi-phase structure resists volume change and delivers excellent cycle stability. • In 10 Sn 10 Bi 80 delivers capacity >250mAh g−1 with retention >98% after 80 cycles. [ABSTRACT FROM AUTHOR]

• The interlayer spacing of V 2 O 5 was adjusted through the intercalation of PEDOT. • V 2 O 5 interacts with PEDOT with the phase transition from Quinoid to Benzoid. • A reversible and fast Mg2+ ion storage of V 2 O 5 /PEDOT was achieved. • The enlarged interlayer and water activation improved the kinetic performances. • Bilayer structured V 2 O 5 /PEDOT achieved the high rate and cycling performances. Magnesium ion batteries (MIBs) are attracting attention as promising alternatives to next-generation energy storage systems owing to their high safety, high volumetric capacity, low reduction potential, abundant raw materials, and economic efficiency. However, developing highly reversible and kinetically fast MIB cathode materials is very challenging owing to the sluggish Mg2+ ion diffusion and low reversible capacity typical of bivalent magnesium ions, as well as the strong electrostatic interactions with the host cathode material. Herein, we designed a charge transfer interaction of a bilayered V 2 O 5 /PEDOT (VOP) complex with involving the phase transition of PEDOT from a quinoid to a benzoid structure which could be realized because of reversible and fast Mg2+ ion storage through an enlarged interlayer spacing of 19.02Å. Furthermore, the effect of water activation on the enhancement of the kinetics was confirmed by conducting electrochemical and in-situ/ex-situ characterizations. Consequently, the as-designed VOP electrodes delivered a high specific capacity of 339.7 mAh/g at 100 mA g−1, high-rate capacity of 256.3 mAh/g at 500 mA g−1, and long-term cyclic stability with a 0.065 % decay rate and high capacity of 172.5 mAh/g after 500 cycles. [ABSTRACT FROM AUTHOR]

Solid electrolytes with high Mg-ion conductivity are required to develop solid-state Mg-ion batteries. The migration energies of the Mg 2+ ions of 5,576 Mg compounds tabulated from the inorganic crystal structure database (ICSD) were evaluated via high-throughput calculations. Among the computational results, we focused on the Mg 2+ ion diffusion in Mg 0.6 Al 1.2  Si 1.8 O 6 , as this material showed a relatively low migration energy for Mg 2+ and was composed solely of ubiquitous elements. Furthermore, first-principles molecular dynamics calculations confirmed a single-phase Mg 2+ ion conductor. The bulk material with a single Mg 0.6 Al 1.2 Si 1.8 O 6 phase was successfully prepared using the sol-gel method. The relative density of the sample was 81%. AC impedance measurements indicated an electrical conductivity of 1.6 × 10 -6 Scm -1 at 500°C. The activation energy was 1.32 eV, which is comparable to that of monoclinic-type Mg 0.5 Zr 2 (PO 4 ) 3 ., (© 2020 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)