Enabling structural and interfacial stability of 5 V spinel LiNi0.5Mn1.5O4 cathode by a coherent interface

Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side stability and maintaining high interfacial kinetics,however,has not yet been resolved.Herein,we design a coherent Li_(1.3)A_(l0.3)Ti_(1.7)(PO)_(4)(LATP)layer that is crystally connected to the spinel LNMO host lattices,which offers fast lithium ions transportation as well as enhances the mechanical stability that prevents the particle fracture.Furthermore,the inactive Li_(3)BO_(3)(LBO)coating layer inhibits the corrosion of transition metals and continuous side reactions.Consequently,the coherent-engineered LNMO-LATPLBO cathode material exhibits superior electrochemical cycling stability in a window of 3.0–5.0 V,for example a high-capacity retention that is 89.7%after 500 cycles at 200 m A g-1obtained and enhanced rate performance(85.1 m A h g^(-1)at 800 m A g^(-1))when tested with a LiPF6-based carbonate electrolyte.Our work presents a new approach of engineering 5 V class spinel oxide cathode that combines interfacial coherent crystal lattice design and surface coating.

Inverse Design of Phononic Crystal with Desired Transmission via a Gradient-Descent Approach

We propose a general approach based on the gradient descent method to study the inverse problem,making it possible to reversely engineer the microscopic configurations of materials that exhibit desired macroscopic properties.Particularly,we demonstrate its application by identifying the microscopic configurations within any given frequency range to achieve transparent phonon transport through one-dimensional harmonic lattices.Furthermore,we obtain the phonon transmission in terms of normal modes and find that the key to achieving phonon transparency or phonon blocking state lies in the ratio of the mode amplitudes at ends.

Interfacial nitrogen engineering of robust silicon/MXene anode toward high energy solid-state lithium-ion batteries

Replacing the conventional carbonate electrolyte by solid-state electrolyte (SSE) will offer improved safety for lithium-ion batteries.To further improve the energy density,Silicon (Si) is attractive for next generation solid-state battery (SSB) because of its high specific capacity and low cost.High energy density and safe Si-based SSB,however,is plagued by large volume change that leads to poor mechanical stability and slow lithium ions transportation at the multiple interfaces between Si and SSE.Herein,we designed a self-integrated and monolithic Si/two dimensional layered T_(3)C_(2)T_(x)(MXene,T_(x) stands for terminal functional groups) electrode architecture with interfacial nitrogen engineering.During a heat treatment process,the polyacrylonitrile not only converts into amorphous carbon (a-C) that shells Si but also forms robust interfacial nitrogen chemical bonds that anchors Si and MXene.During repeated lithiation and delithiation processes,the robust interfacial engineered Si/MXene configuration enhances the mechanical adhesion between Si and MXene that improves the structure stability but also contributes to form stable solid-electrolyte interphase (SEI).In addition,the N-MXene provides fast lithium ions transportation pathways.Consequently,the Si/MXene with interfacial nitrogen engineering (denoted as Si-N-MXene) deliveres high-rate performance with a specific capacity of 1498 m Ah g^(-1) at a high current of 6.4 A g^(-1).A Si-N-MXene/NMC full cell exhibited a capacity retention of 80.5%after 200 cycles.The Si-N-MXene electrode is also applied to SSB and shows a relative stable cycling over 100 cycles,demonstrating the versatility of this concept.

Any-polar resistive switching behavior in Ti-intercalated Pt/Ti/HfO_(2)/Ti/Pt device

The special any-polar resistive switching mode includes the coexistence and stable conversion between the unipolar and the bipolar resistive switching mode under the same compliance current.In the present work,the any-polar resistive switching mode is demonstrated when thin Ti intercalations are introduced into both sides of Pt/HfO_(2)/Pt RRAM device.The role of the Ti intercalations contributes to the fulfillment of the any-polar resistive switching working mechanism,which lies in the filament constructed by the oxygen vacancies and the effective storage of the oxygen ion at both sides of the electrode interface.

Mechanical properties and enhancement mechanisms of titanium-graphene nanocomposites

Molecular dynamics(MD)simulations of the titanium-graphene nanocomposites(TiGNCs)under uniaxial tension are carried out to investigate the mechanical properties and reinforcement mechanism of graphene in composites.It is found that introduction of mechanically robust graphene limits the strain-induced dislocation and araorphization and thereby highly improves the mechanical properties of metallic titanium that are greatly affected by the crystal stacking orientation of graphene and titanium layers.The thickness of titanium layers,interface interaction and working temperature play an important role in the mechanical strength and elastic moduli of composites.The results show the mechanical properties of TiGNCs are monotonically enhanced with reduction of the titanium layer thickness and working temperature,and the Young5s modulus obtained by MD simulation are higher than that predicted by the rule of mixture(ROM)due to consideration of interfacial interaction in computational calculation.In addition,once the critical thickness of titanium layer is reached,graphene wrinkles are induced in composites because of Poisson's effect induced large lateral compression stress in the interface region.This study provides helpful insights into fundamental understanding reinforcing mechanism of graphene and ultimately contribute to the optimal design and performance of mechanically robust graphene-based metallic composites.

Optical vortex copier and regenerator in the Fourier domain

The generation and manipulation of optical vortices are of fundamental importance in a variety of promising applications. Here, we develop a nonlinear optical paradigm to implement self-and cross-convolution of optical vortex arrays, demonstrating the features of a vortex copier and regenerator. We use a phase-only spatial light modulator to prepare the 1064 nm invisible fundamental light to carry special optical vortex arrays and use a potassium titanyl phosphate crystal to perform type Ⅱ second-harmonic generation in the Fourier domain to achieve 532 nm visible structured vortices. Based on pure cross-convolution, we succeed in copying arbitrary-order single vortices as well as their superposition states onto a prearranged array of fundamental Gaussian spots. Also, based on the simultaneous effect of self-and cross-convolutions, we can expand the initial vortex lattices to regenerate more vortices carrying various higher topological charges. Our presented method of realizing an optical vortex copier and regenerator could find direct applications in optical manipulation, optical imaging, optical communication, and quantum information processing with structured vortex arrays.

用于柔性智能变色玻璃的叶脉状分级银网络透明电极

呈现出可逆颜色变化的智能窗户可调节阳光的透射,节省大量的能耗.目前,在众多智能玻璃中,柔性电致变色器件由于可实现卷对卷生产,良好的控制性以及与其他能源(太阳能电池和锂电池)的兼容性而受到广泛关注.因此,作为柔性电致变色器件不可或缺的部分,柔性透明电极变得越来越重要.本文基于叶脉状的分层金属网络构造了大面积的柔性透明电极,该多级网络由介观尺度的"树干"和微观尺度的"分支"组成.自发形成的"分支"使导电路径均匀分布,而激光蚀刻的"树干"则能够将收集的电子进行远距离传输.该透明电极表现出高的透光率(~81%)和低的电阻(1.36Ωsq–1),并可通过调整网格的宽度、边长和裂纹图案的大小来优化性能.在此基础上,制造了具有显著循环性能的柔性电致变色器件.具有高透明度、导电性和柔韧性的多级银网络透明电极未来将可能在下一代柔性可穿戴光电设备中有广泛的应用前景.

Thermally activated phase transitions in Fe-Ni core-shell nanoparticles

Fe-Ni core-shell nanoparticles are versatile functional materials,and their thermal stabilities are crucial for their performances in operating conditions.In this study,the thermodynamic behaviors of Fe-Ni core-shell nanoparticles are examined under continuous heating.The solid-solid phase transition from body centered cubic(bcc)to face centered cubic(fcc)in the Fe core is identified.The transition is accompanied with the generation of stacking faults around the core-shell interface,which notably lowers the melting points of the Fe-Ni core-shell nanoparticles and causes even worse thermal stability compared with Ni ones.Moreover,the temperature of the structural transformation is shown to be tuned by modifying the Ni shell thickness.Finally,the stress distributions of the core and the shell are also explored.The relevant results could be helpful for the design,preparation,and utilization of Fe-based nanomaterials.

Quantum information transfer between a two-level and a four-level quantum systems

Quantum mechanics provides a disembodied way to transfer quantum information from one quantum object to another.In theory,this quantum information transfer can occur between quantum objects of any dimension,yet the reported experiments of quantum information transfer to date have mainly focused on the cases where the quantum objects have the same dimension.Here,we theoretically propose and experimentally demonstrate a scheme for quantum information transfer between quantum objects of different dimensions.By using an optical qubit-ququart entangling gate,we observe the transfer of quantum information between two photons with different dimensions,including the flow of quantum information from a four-dimensional photon to a twodimensional photon and vice versa.The fidelities of the quantum information transfer range from 0.700 to 0.917,all above the classical limit of 2/3.Our work sheds light on a new direction for quantum information transfer and demonstrates our ability to implement entangling operations beyond two-level quantum systems.