Status and challenges facing representative anode materials for rechargeable lithium batteries

Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.

Effect of staggered array structure on the flow field of micro gas chromatographic column

A new design of staggered array semi-packed micro gas chromatographic column was presented based on the micro electromechanical system(MEMS)technology.It was a sensor for gas sample analysis.The internal velocity fields of ten types of semi-packed micro gas chromatographic column were studied.The effects of array spacing and dislocation spacing on the flow field distribution were investigated.The results show that on the basis of ensuring the formation of virtual wall,with the increase of array spacing,the maximum velocity difference between the flow channels in the vertical direction decreases gradually,but the velocity difference in the flow channels a and b increases.When the inlet velocity was set to be 0.18 m/s,the maximum velocity difference in the channel of the staggered semi-packed micro gas chromatography column 3(CSAC3)was 0.05610 m/s.The maximum velocity difference in the channel a was 0.09160 m/s.The maximum velocity difference in the channel b was 0.02401 m/s.CSAC3 had a more uniform velocity field distribution,which can effectively suppress the laminar flow effect during chromatographic separation,and had a smaller pressure distribution,which puts forward lower requirements for carrier gas system.The staggered array semi-packed micro gas chromatography column proposed in this paper can effectively improve the velocity field distribution and pressure distribution in the channel,and provide a theoretical basis for the design of the new micro gas chromatography column structure.

High-sensitivity Bloch surface wave sensor with Fano resonance in grating-coupled multilayer structures

A new type of device consisting of a lithium niobate film coupled with a distributed Bragg reflector(DBR)was theoretically proposed to explore and release Bloch surface waves for applications in sensing and detection.The film and grating made of lithium niobate(LiNbO_(3))were placed on both sides of the DBR and a concentrated electromagnetic field was formed at the film layer.By adjusting the spatial incidence angle of the incident light,two detection and analysis modes were obtained,including surface diffraction detection and guided Bloch detection.Surface diffraction detection was used to detect the gas molecule concentrations,while guided Bloch detection was applied for the concentration detection of biomolecule-modulated biological solutions.According to the drift of the Fano curve,the average sensor sensitivities from the analysis of the two modes were 1560°/RIU and 1161°/RIU,and the maximum detection sensitivity reached2320/RIU and 2200°/RIU,respectively.This study revealed the potential application of LiNbO_(3)as a tunable material when combined with DBR to construct a new type of biosensor,which offered broad application prospects in Bloch surface wave biosensors.

Micro-scale Realization of Compliant Mechanisms:Manufacturing Processes and Constituent Materials-A Review

Compliant micromechanisms(CMMs)acquire mobility from the deflection of elastic members and have been proven to be robust by millions of silicon MEMS devices.However,the limited deflection of silicon impedes the realization of more sophisticated CMMs,which often require larger deflections.Recently,some novel manufacturing processes have emerged but are not well known by the community.In this paper,the realization of CMMs is reviewed,aiming to provide help to mechanical designers to quickly find the proper realization method for their CMM designs.To this end,the literature surveyed was classified and statistically analyzed,and representative processes were summarized individually to reflect the state of the art of CMM manufacturing.Furthermore,the features of each process were collected into tables to facilitate the reference of readers,and the guidelines for process selection were discussed.The review results indicate that,even though the silicon process remains dominant,great progress has been made in the development of polymer-related and composite-related processes,such as micromolding,SU-8 process,laser ablation,3D printing,and the CNT frameworking.These processes result in constituent materials with a lower Young’s modulus and larger maximum allowable strain than silicon,and therefore allow larger deflection.The geometrical capabilities(e.g.,aspect ratio)of the realization methods should also be considered,because different types of CMMs have different requirements.We conclude that the SU-8 process,3D printing,and carbon nanotube frameworking will play more important roles in the future owing to their excellent comprehensive capabilities.