Lithium-metal fl uoride (MF) batteries offer the highest theoretical energy density, exceeding that of the sulfur-lithium cells. However, conversion-type MF cathodes suffer from high resistance, small capacity utilization at room temperature, irreversible structural changes, and rapid capacity fading with cycling. In this study, the successful application of the approach to overcome such limitations and dramatically enhance electrochemical performance of Li-MF cells is reported. By using iron fl uoride (FeF 2 ) as an example, Li-MF cells capable of achieving near-theoretical capacity utilization are shown when MF is infi ltrated into the carbon mesopores. Most importantly, the ability of electrolytes based on the lithium bis(fl uorosulfonyl)imide (LiFSI) salt is presented to successfully prevent the cathode dissolution and leaching via in situ formation of a Li ion permeable protective surface layer. This layer forms as a result of electrolyte reduction/oxidation reactions during the fi rst cycle of the conversion reaction, thus minimizing the capacity losses during cycling. Postmortem analysis shows the absence of Li dendrites, which is important for safer use of Li metal anodes. As a result, Li-FeF 2 cells demonstrate over 1000 stable cycles. Quantum chemistry calculations and postmortem analysis provide insights into the mechanisms of the passivation layer formation and the performance boost.

The electron-beam welding (EBW) behaviors of pure Mg and the AZ31, AZ61, and AZ91 Mg alloys are examined in this study, in terms of fusion-zone characteristics, grain structures, texture evolution, and joint efficiency. With increasing A1 content, the Mg-based materials were found to be more easily fusion welded. The AZ91 alloy could be welded using a beam power of 2200 W and a weld speed of 16 mm/s, resulting in a weld depth of 29 mm with a fusion-zone aspect ratio of 8.2. The grains inside the fusion zone were nearly equiaxed in shape and ϳ10 m in size, due to the rapid cooling rate. Extended partial melting zones were observed in alloys with high solute contents, such as AZ61 and AZ91. The postweld tensile strength of the Mg alloys could recover back to ϳ80 to 110 pct of the original strength. The texture in the fusion zone was traced by X-ray diffraction (XRD) and electron-backscattered diffraction (EBSD). The grain orientations inside the rapidly solidified electron-beam-welded fusion zones are still rather diversely distributed. The a 1 -, a 2 -, and a 3 -axes of some grains tend to align at 90 or 30 deg with respect to welding direction, and the c-axis tends to align along the plate normal direction. The influence from surface tension on the weld top-surface appearance and weld depth was not pronounced for the current four Mg materials. Instead, differences in the solidus temperatures and thermal conductivity should be the primary factors.

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With the development of information industries, abundant waste toner was produced along with the generation of waste toner cartridges in office works. Waste toner is considered a hazardous material due to the small size (2–7 μm) and components of polystyrene, polyacrylate, Fe3O4, and SiO2. Cancers of blood circulation and digestive systems will be induced if toner is inhaled. According to our knowledge, little information was published about the disposal technology of waste toner. This paper proposes an environmentally-friendly technology to dispose waste toner. Vacuum-gasification-condensation was employed to treat waste toner. Industrial chemicals, n-butene gas, and liquid oils of styrene, polystyrene, and acrylic ester were obtained from the pyrolysis of polystyrene and polyacrylate. The organics of waste toner began to be decomposed and gasified when the temperature reached 450 °C. Above 570 °C, most of the polystyrene and polyacrylate were converted to gases and then condensed into oil in the temperatures of 180 and 80 °C. SiO2 and Fe3O4 of waste toner were transformed into nano-Fe3O4 and nano-SiO2 and gathered. The size of the nanoparticles was about 200 nm. This paper provides a recovery technology of waste toner that is environmentally-friendly and high value-added.