Nb-Doped TiO2 with Outstanding Na/Mg-Ion Battery Performance.

The group "beyond Li-ion" batteries (Na/Mg-ion batteries) have the advantages of abundant reserves and high theoretical specific capacity. However, the sluggish kinetics resulting from large ion radius (Na+) and polarity (Mg2+) seriously limit the battery performance. Herein, we prepared Nb-doped anatase TiO2 with Ti vacancies (Nb-TiO2) through a simple solvothermal and subsequent calcination process. The Nb doping widens the channels for metal ion diffusion, and the cationic vacancies can act as ion storage sites and improve the electrode conductivity. Thus, Nb-TiO2 exhibits improved performance for rechargeable Na/Mg-ion batteries.

The Degradation Properties of MgO Whiskers/PLLA Composite In Vitro.

In this study, composite films of stearic acid⁻modified magnesium oxide whiskers (Sa⁻w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO whiskers through neutralization of the acidic product of PLLA degradation. The cytocompatibility of the composites also increased remarkably, as determined from the cell viability results, and was higher than that of PLLA at the chosen whisker content. This was beneficial for the cell affinity of the material, as it notably led to an enhanced biocompatibility of the PLLA, in favor of promoting cell proliferation, which significantly improved its bioactivity, as well.

In vitro and in vivo corrosion, mechanical properties and biocompatibility evaluation of MgF2-coated Mg-Zn-Zr alloy as cancellous screws.

Magnesium (Mg) and its alloys as biodegradable materials have received much attention in the orthopedics applications; however, the corrosion behavior of these metals in vivo remains challenging. In this work, a dense and nanoscale magnesium fluoride (MgF2) coating was deposited on the surface of Mg-Zn-Zr (MZZ) alloy cancellous screw. The MZZ cancellous screw with MgF2 coating maintained an integrated shape and high yield tensile stress after 30days immersion in SBF, comparing with the bare screw. Hydrogen releasing rate of the MZZ samples was suppressed at a lower level at the initial stage, which is in favour of the adhesion of the cells. And in vivo experiments indicated that MgF2-coated MZZ screws presented advantages in cytocompatibility, osteoconductivity and osteogenesis of cancellous bone in rabbits. Corrosion rate in vivo perfusion environment increased very slowly with time in long-term study, which was an opposite trend in vitro static immersion test. Moreover, maximum corrosion rate (CRmax), a critical calculation method of corrosion rate was introduced to predict fracture regions of the sample. The MZZ alloy with MgF2 coating possesses a great potential for clinical applications for internal fracture fixation repair.