In situ Nanomechanical Research on Large-Scale Plastic Deformation of Individual Ultrathin Multi-walled Carbon Nanotube

Carbon nanotubes are a promising candidate for the application of flexible electronics due to the ultrahigh intrinsic conductivity and excellent mechanical flexibility. In the present work, the morphology of the ultrathin (diameter<20 nm) multi-walled carbon nanotubes (MWCNTs) under an axial compression was investigated by using in-situ transmission electron microscopy. Moreover, the overall dynamic deformation processes and the force-displacement (F-D) curves of the MWCNTs were also examined. Interestingly, the MWCNTs almost restored their original morphology after 15 loading-unloading cycles. The deformation and recovery process indicate that the MWCNTs are flexible and exhibit excellent durability against compression. The Young’s modulus of the MWCNTs is estimated with the value of ∽0.655 TPa derived from the F-D curves fitting. Our results suggest that the ultrathin carbon nanotube structures may have great application potentials in flexible devices.

Significant effect of ordered micro-domain on cell boundary phase distribution and demagnetization curve squareness of Sm_(2)Co_(17)-type magnet

Cu-rich cell boundary phase is difficult to precipitate evenly,resulting in a generally poor demagnetization curve squareness for Fe-rich Sm_(2)Co_(17)-type magnet,which is a key factor limiting the further improvement of magnetic energy product.In this study,we report that nanoscale strip-like ordered micro-domains distributed in1:7H disordered matrix phase of the solid solution precursor is a new factor significantly affecting the precipitation and distribution of the cell boundary phase.Long strip-like and continuous micro-twin structure with twin boundaries neatly perpendicular to the C-axis is observed after sintering treatment.After solution treatment,sequential and long strip-like micro-twins gradually transform into disordered state along the basal plane,forming narrow disordered 1:7H(TbCu_(7)-type structure)phase between the separated strip-like ordered micro-domains.This disordering transformation takes place via broken down of the long strip-like ordered micro-domains,which is accomplished by narrowing along the width direction followed by reduction of the length.Furthermore,a new model revealing the effect of the ordered micro-domains on the formation of the cell boundary phase is proposed.Antiphase boundaries enriched in Cu have already existed in the precursor with long strip-like ordered micro-domains.Therefore,the Cu-rich cell boundary phase acting as strong pinning centers cannot be precipitated homogeneously and distributed continuously after aging,resulting in a poor demagnetization curve squareness of Sm_(2)Co_(17)-type magnet.Our results indicate that significant broken down of the nanoscale ordered micro-domains in solution precursor is the key factor improving the distribution of cell boundary phase in Sm_(2)Co_(17)-type magnets.

Stabilized cathode/sulfide solid electrolyte interface via Li_(2)ZrO_(3)coating for all-solid-state batteries

High-capacity LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM)cathode is essential for realizing high energy density all-solid-state lithium batteries.However,the space charge layer effect between NCM cathode and the commonly used sulfide solid electrolyte results in deterioration of the battery performance.In this work,a 10-nm electrochemical stable Li_(2)ZrO_(3)(LZO)layer was in situ coated on the surface of NCM particles through facile wet chemical method.