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With the lightest green structural material for 21st century, a significant weight reduction effect was expected to solve the lightweight problem in aerospace and other fields. However, the material's poor mechanical properties and flammability limited its widely application in such fields. In this paper, the GWK series alloys (Mg-5.3Gd-4.11Y-0.13Zr, Mg-5.5Gd-4.22Y-0.19Zr, and Mg-5.46Gd-4.02Y-0.20Zr, in wt.%) were designed, and we explored the effect of alloy composition and process on the microstructure and properties of GWK series alloys subject to casting, homogenization, extrusion, ageing and ignition. The result show that Mg-5.3Gd-4.11Y-0.13Zr alloy after T4 treatment at 500 °C/6 h obtains an excellent solid solution effect. In addition, the aged alloy shows a good balance of mechanical properties, a tensile strength of 405 MPa, yield strength of 275 MPa, as well as elongation of 8.12%, and excellent non-flammability. [ABSTRACT FROM AUTHOR]

With the lightest green structural material for 21st century, a significant weight reduction effect was expected to solve the lightweight problem in aerospace and other fields. However, the material’s poor mechanical properties and flammability limited its widely application in such fields. In this paper, the GWK series alloys (Mg-5.3Gd-4.11Y-0.13Zr, Mg-5.5Gd-4.22Y-0.19Zr, and Mg-5.46Gd-4.02Y-0.20Zr, in wt.%) were designed, and we explored the effect of alloy composition and process on the microstructure and properties of GWK series alloys subject to casting, homogenization, extrusion, ageing and ignition. The result show that Mg-5.3Gd-4.11Y-0.13Zr alloy after T4 treatment at 500 °C/6 h obtains an excellent solid solution effect. In addition, the aged alloy shows a good balance of mechanical properties, a tensile strength of 405 MPa, yield strength of 275 MPa, as well as elongation of 8.12%, and excellent non-flammability.

The effect of Al content on the texture evolution and recrystallization behavior of the non-flammable Mg sheet alloys containing Ca and Y was investigated in this study. With a decrease in the Al content from 3 wt.% to 1 wt.%, the amounts of the other alloying elements dissolved in the matrix, especially Ca, are increased. The increase of the alloying elements in a solid solution brought out the retarded recrystallization and weakened texture with the basal poles tilted toward the sheet transverse direction. Extension twinning activity increased when Al content with decreasing, resulting in the texture broadening towards the sheet transverse direction in the as-rolled sheets. The textures of the AZXW1000 and AZXW2000 sheets weaken uniformly in all sample directions during annealing, while the AZXW3000 sheet shows less weakening of the rolling direction split component. The texture weakening of the alloys with lower Al contents is attributed to the retarded recrystallization caused by the larger amount of the dissolved Ca solutes. Based on the non-basal texture and relatively stable grain structure, the Mg alloy sheet containing a relatively small amount of Al is advantageous to improve the formability.

A new Mg alloy with the composition of Mg-8Al-0.3Zn-0.1Mn-0.3Ca-0.2Y was successfully fabricated by a low-temperature, low-speed indirect extrusion process. The extruded alloy showed excellent mechanical properties, i.e., a tensile yield strength of 379.3 MPa, ultimate tensile strength of 421.7 MPa, elongation of 11.3%, and yield asymmetry of 0.95, as well as a very high chip ignition temperature of 820 °C. The outstanding mechanical properties are attributed to the microstructural characteristics of the extruded alloy, that is, (i) grain boundary strengthening by fine recrystallized grains, (ii) precipitation hardening by abundant fine Mg 17 Al 12 precipitates, and (iii) strain hardening by the deformed non-recrystallized region with a strong basal texture that is unfavorable for basal slip during tension. Electron backscatter diffraction results showed that no twinning occurred in the recrystallized grains, which had a very small size of approximately 800 nm, whereas {10–12} twins were formed in the non-recrystallized grains even at low compressive stress, which consequently increased the yield asymmetry. [ABSTRACT FROM AUTHOR]

The anode properties of Nb-doped rutile TiO 2 electrodes were investigated in an ionic liquid electrolyte comprised of N -methyl- N -propylpyrrolidinium cation and bis(fluorosulfonyl)amide anion for use in a safe Na-ion battery. Although the electrolyte's conductivity was lower than that of a conventional organic electrolyte at 30 °C, it showed high conductivity comparable to that of the organic electrolyte at 60 °C. The Nb-doped TiO 2 electrode showed excellent cyclability in the ionic liquid electrolyte at 60 °C: a high capacity retention of 97% was observed even at the 350th cycle, which is comparable to value in the organic electrolyte (91%). In a non-flammability test in a closed system, no ignition was observed with the ionic liquid electrolyte even at 300 °C. These results indicate that combination of a Nb-doped TiO 2 anode and ionic liquid electrolyte gives not only an excellent cyclability but also high safety for a Na-ion battery operating at a temperature below the sodium's melting point of 98 °C. [ABSTRACT FROM AUTHOR]

Abstract: Novel binary electrolytes based on ionic liquid (N-butyl-methyl piperidinium bis(trifluoro-methylsulfonyl)imide, PP14-TFSI) and sulfone (tetramethylene sulfone, TMS) have been prepared and examined for use in lithium-ion batteries. The addition of sulfone is expected to improve the lithium salts solvability, ionic conductivity and electrode compatibility of the ionic liquid greatly. More importantly, the addition of sulfone is not expected to deteriorate the peculiar properties of the ionic liquid, such as the wide electrochemical window and non-flammability. Experimental results have shown that the reversible discharge capacities of the Li/LiFePO4 half-cell, which contains a 0.5 M LiTFSI/(60%) PP14-TFSI/(40%) TMS mixed electrolyte at a current density of 0.05 C and 1 C, can reach up to 160 and 150 mAh g−1, respectively, which are much higher than the discharge capacity achieved using the pure ionic liquid electrolyte under the same conditions. Furthermore, lithium difluoro(oxalato)borate (LiDFOB) has been found to have positive effects on the battery performance of the mixed electrolytes. The 0.5 M LiDFOB/(60%) PP14-TFSI/(40%) TMS mixed electrolyte exhibits better compatibility with the Li1.2Ni0.2Mn0.6O2 cathode than conventional electrolytes, where an initial discharge capacity of 255 mAh g−1 is obtained and a stable capacity of above 230 mAh g−1 is retained after 30 cycles. [Copyright &y& Elsevier]

Today, the requirement for clean, highly efficient, and safe energy seems to be higher and higher due to non-renewable energy and pollution of the environment. At this moment, lithium-ion batteries (LIBs) look like a reliable solution for this dilemma since they have huge energy density. However, the flammability of the conventional electrolyte used in the LIBs is one of critical disadvantages of LIBs, which compromises the safety issue of LIBs. Herein, we reported a non-flammable zwitterionic ionic liquid-based electrolyte named TLPEC, which was fabricated by simply mixing a novel zwitterionic ionic liquid TLP (93 wt%) and ethylene carbonate (EC, 7 wt%). The TLPEC electrolyte exhibited a wide electrochemical potential window of 1.65–5.10 V and a robust ionic conductivity of 1.0 × 10−3 S cm−1 at 20 °C, which renders TLPEC to be a suitable electrolyte for LIBs with enhanced safety performance. The LIBs, with TLPEC as the electrolyte, exhibited an excellent performance in terms of excellent rate capability, cycling stability, and high specific capacity at 25 and 60 °C, which were attributed to the stability and high ionic conductivity of TLPEC electrolyte during cycling as well as the excellent interface compatibility of TLPEC electrolyte with lithium anode. [ABSTRACT FROM AUTHOR]

The effect of Al content on the texture evolution and recrystallization behavior of the non-flammable Mg sheet alloys containing Ca and Y was investigated in this study. With a decrease in the Al content from 3 wt.% to 1 wt.%, the amounts of the other alloying elements dissolved in the matrix, especially Ca, are increased. The increase of the alloying elements in a solid solution brought out the retarded recrystallization and weakened texture with the basal poles tilted toward the sheet transverse direction. Extension twinning activity increased when Al content with decreasing, resulting in the texture broadening towards the sheet transverse direction in the as-rolled sheets. The textures of the AZXW1000 and AZXW2000 sheets weaken uniformly in all sample directions during annealing, while the AZXW3000 sheet shows less weakening of the rolling direction split component. The texture weakening of the alloys with lower Al contents is attributed to the retarded recrystallization caused by the larger amount of the dissolved Ca solutes. Based on the non-basal texture and relatively stable grain structure, the Mg alloy sheet containing a relatively small amount of Al is advantageous to improve the formability. [ABSTRACT FROM AUTHOR]

• Non-flammable electrolyte with TMP and F-EPE improves the safety of SIB. • TMP/F-EPE electrolyte stabilizes the interface of NFM cathode during all processes. • The cycling life of NFM/HC pouch cell increases by using TMP/F-EPE electrolyte. Despite their beneficial effect on battery safety, non-flammable electrolytes often have an adverse side effect on the electrochemical performance of lithium and sodium ion batteries due to their poor compatibility with the electrodes. In this paper, we report a new non-flammable electrolyte consisting of trimethyl phosphate (TMP) and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (F-EPE) as non-flammable solvents and fluoroethylene carbonate (FEC) as additive with different concentration of Na salts, and a EC-DEC-FEC electrolyte was also prepared as baseline electrolyte. The flammability and non-flammability of the prepared electrolytes was tested. It is shown that the prepared electrolyte not only increases the capacity (129.9 vs. 122.5 mAh g−1 of baseline electrolyte) of NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM) cathode but also stabilizes the cyclability (70.8% retention after 500 cycles) of NFM/HC (HC: hard carbon) pouch cells. The dissolution of pristine NaNi 1/3 Fe 1/3 Mn 1/3 O 2 cathode material in different solvents and electrolytes, and the XPS patterns of the cycled NFM cathode in the prepared electrolytes were also studied to understand the capacity fading mechanism. These results indicate that this new non-flammable electrolyte holds great potential for application in rechargeable sodium-ion batteries. [ABSTRACT FROM AUTHOR]