A general synthesis of inorganic nanotubes as high-rate anode materials of sodium ion batteries

Ino rganic tubular materials have an exceptionally wide range of applications,yet developing a simple and universal method to controllably synthesize them remains challenging.In this work,we report a vaporphase-etching hard-template method that can directly fabricate tubes on various thermally stable oxide and sulfide materials.This synthesis method features the introduction of a vapor-phase-etching process to greatly simplify the steps involved in preparing tubular materials and avoids complicated postprocessing procedures.Furthermore,the in-situ heating transmission electron microscopy(TEM)technique is used to observe the dynamic formation process of TiO_(2-x) tubes,indicating that the removal process of the Sb2S3 templates first experienced the Rayleigh instability,then vapor-phase-etching process.When used as an anode for sodium ion batteries,the TiO_(2-x) tube exhibits excellent rate performance of134.6 mA h g^(-1) at the high current density of 10 A g^(-1) and long-term cycling over 7000 cycles.Moreover,the full cell demonstrates excellent cycling performance with capacity retention of 98%after 1000 cycles,indicating that it is a promising anode material for batteries.This method can be expanded to the design and synthesis of other thermally-stable tubular materials such as ZnS,MoS_(2),and SiO_(2).

A mussel-inspired delivery system for enhancing self-healing property of epoxy coatings

Dopamine(DA), one type of mussel-inspired biological molecules with adhesive nature and corrosion inhibitor property, are often used to functionalize the surfaces of various materials. Herein, we report the application of polydopamine(PDA) microcapsules as novel nanocontainers for the purpose, loading corrosion inhibitor(benzotriazole) in its shell structure, and then were embedded into epoxy coatings to provide self-healing and anti-corrosion protection for carbon steel. Fast release of benzotriazole in acidic environment caused by local corrosion and the chelating effect of PDA-Fe^(3+)can synergistically promote the formation of protective film on bare steel surface, which endows coatings with self-healing functionality. Electrochemical impedance spectroscopy(EIS), local electrochemical impedance spectroscopy(LEIS), and spray tests were conducted to evaluate the active inhibition and corrosion resistance of the loaded coatings. The scratched coating with incorporation of nanocontainers presented better protection performance, exhibiting increased Ro(oxide layer resistance) and R ct(charge transfer resistance) during initial immersion periods. The EIS tests in long-term immersion were also performed to confirm the anti-corrosion effect of composited coatings. These results demonstrated that benzotriazole-decorated PDA capsules dramatically enhanced the self-healing properties and anti-corrosion performance of epoxy coatings with the synergistic help of PDA and benzotriazole.