Highly aligned lithiophilic electrospun nanofiber membrane for the multiscale suppression of Li dendrite growth

Using inorganic fibrous membranes as protective layers has yielded success in suppressing dendrite growth.However,conventional fibrous membranes usually have large voids and low affinity for Li,promoting inhomogeneous charge distribution and allowing some dendrites to grow.Herein,we introduce a highly aligned TiO_(2)/SiO_(2)(A-TS)electrospun nanofiber membrane as a protective layer for the Li metal anode.The A-TS membrane is fabricated by a custom-made electrospinning system with an automatic fiber alignment collector that allows control of the fibers’orientation.At the scale of the individual fibers,their high binding energies with Li can attract more“dead”Li by reacting with the SiO_(2) component of the composite,avoiding uncontrollable deposition on the metal anode.At the membrane scale,these highly ordered structures achieve homogeneous contact and charge distribution on the Li metal surface,leaving no vulnerable areas to nucleate dendrite formation.Additionally,the excellent mechanical and thermal stability properties of the A-TS membrane prevent any potential puncturing by dendrites or thermal runaway in a battery.Hence,an A-TS@Li anode exhibits stable cycling performance when used in both Li-S and Li-NCM811 batteries,highlighting significant reference values for the future design and development of high-energy-density metal-based battery systems.

Non-Local and Memory Character of Frictional Energy Dissipation on Atomic Scale

The traditional description of atomic-scale friction, as investigated in Friction force microscopy, in terms of mechanical stick-slip instabilities appears so successful that it obscures the actual mechanisms of frictional energy dissipation. More sophisticated theoretical approach, which takes into account damping explicitly, reveals the existence of some hidden, unexplained problems, like the universal nearly-critical damping and unexpectedly high value of the dissipation rate. In this paper, we combine analysis in the framework of nonequilibrium statistical mechanics with simple atomistic modeling to show that the hidden problems of atomic scale friction find their origin in the nontrivial character of energy dissipation that is non-local and dominated by memory effects, which have not been addressed before in the context of dry, atomic-scale friction.

Non-isoplanatic lens aberration correction in dark-field digital holographic microscopy for semiconductor metrology

In the semiconductor industry,the demand for more precise and accurate overlay metrology tools has increased because of the continued shrinking of feature sizes in integrated circuits.To achieve the required sub-nanometre precision,the current technology for overlay metrology has become complex and is reaching its limits.Herein,we present a dark-field digital holographic microscope using a simple two-element imaging lens with a high numerical aperture capable of imaging from the visible to near-infrared regions.This combination of high resolution and wavelength coverage was achieved by combining a simple imaging lens with a fast and accurate correction of non-isoplanatic aberrations.We present experimental results for overlay targets that demonstrate the capability of our computational aberration correction in the visible and near-infrared wavelength regimes.This wide-ranged-wavelength imaging system can advance semiconductor metrology.

Endo-microscopy beyond the Abbe and Nyquist limits

For several centuries,far-field optical microscopy has remained a key instrument in many scientific disciplines,including physical,chemical,and biomedical research.Nonetheless,far-field imaging has many limitations:the spatial resolution is controlled by the diffraction of light,and the imaging speed follows the Nyquist–Shannon sampling theorem.The recent development of super-resolution techniques has pushed the limits of spatial resolution.However,these methods typically require complicated setups and long acquisition times and are still not applicable to deeptissue bioimaging.Here,we report imaging through an ultra-thin fibre probe with a spatial resolution beyond the Abbe limit and a temporal resolution beyond the Nyquist limit simultaneously in a simple and compact setup.We use the random nature of mode coupling in a multimode fibre,the sparsity constraint and compressive sensing reconstruction.The new approach of super-resolution endo-microscopy does not use any specific properties of the fluorescent label,such as depletion or stochastic activation of the molecular fluorescent state,and therefore can be used for label-free imaging.We demonstrate a spatial resolution more than 2 times better than the diffraction limit and an imaging speed 20 times faster than the Nyquist limit.The proposed approach can significantly expand the realm of the application of nanoscopy for bioimaging.

Mechanochemical reactions of GaN-Al_(2)O_(3) interface at the nanoasperity contact:Roles of crystallographic polarity and ambient humidity

Mechanochemical reactions of the GaN-Al_(2)O_(3) interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining.In this work,the mechanochemical reactions on Ga-and N-faced GaN surfaces rubbed by the Al_(2)O_(3) nanoasperity as a function of the environmental humidity were investigated.Experimental results indicate that the N-face exhibits much stronger mechanochemical removal over the relative humidity range of 20%-80%than the Ga-face.Increasing water molecules in environmental conditions significantly promotes the interfacial mechanochemical reactions and hence accelerates the atomic attrition on N-face.The hypothesized mechanism of the selective water-involved mechanochemical removal is associated with the dangling bond configuration,which affects the mechanically-stimulated chemical reactions via altering the activation energy barrier to form the bonding bridge across the sliding interface.These findings can enrich the understanding of the underlying mechanism of mechanochemical reactions at GaN-Al_(2)O_(3) interface and a broad cognition for regulating the mechanochemical reactions widely existing in scientific and engineering applications.

Electrochemically-stimulated nanoscale mechanochemical wear of silicon

Mechanochemical reactions at the sliding interface between a single-crystalline silicon(Si)wafer and a silica(SiO2)microsphere were studied in three environmental conditions:humid air,potassium chloride(KCl)solution,and KCl solution with an applied voltage.Compared to that from humid air,mechanochemical material removal from the silicon surface increased substantially in the KCl-immersed condition,and further increased when electrochemistry was introduced into the tribological system.By measuring the load dependence of the material removal rate and analyzing the results using a mechanically assisted Arrhenius-type kinetic model,the activation energy(E_(a))and the mechanical energy(E_(m)),by which this energy is reduced by mechanical activation,were compared qualitatively under different environmental conditions.In the KCl-immersed condition,mechanochemistry may decrease the required effective energy of reactions(E_(eff)=E_(a)−E_(m))and promote material removal mainly through improved catalysis of the mechanochemical reactions facilitated by greater availability of water molecules compared to the humid air condition.Thus,the effectiveness of the mechanochemistry is improved.In the electrochemical condition,electrochemically-accelerated oxidation of the silicon surface was confirmed by the X-ray photoelectron spectroscopy(XPS)characterization.The results strongly suggest that electrochemistry further stimulates mechanochemical reactions primarily by increasing the initial energy state of the surface via the facilitated formation of interfacial bonding bridges,i.e.,a surface oxidation/hydroxylation process.