Interface and mechanical degradation mechanisms of the silicon anode in sulfide-based solid-state batteries at high temperatures

Silicon(Si)is a competitive anode material owing to its high theoretical capacity and low electrochemical potential.Recently,the prospect of Si anodes in solid-state batteries(SSBs)has been proposed due to less solid electrolyte interphase(SEI)formation and particle pulverization.However,major challenges arise for Si anodes in SSBs at elevated temperatures.In this work,the failure mechanisms of Si-Li_(6)PS_(5)Cl(LPSC)composite anodes above 80℃are thoroughly investigated from the perspectives of interface stability and(electro)chemo-mechanical effect.The chemistry and growth kinetics of Lix Si|LPSC interphase are demonstrated by combining electrochemical,chemical and computational characterizations.Si and/or Si–P compound formed at Lix Si|LPSC interface prove to be detrimental to interface stability at high temperatures.On the other hand,excessive volume expansion and local stress caused by Si lithiation at high temperatures damage the mechanical structure of Si-LPSC composite anodes.This work elucidates the behavior and failure mechanisms of Si-based anodes in SSBs at high temperatures and provides insights into upgrading Si-based anodes for application in SSBs.

Virtual fire drill system supporting co-located collaboration

Background Due to the restriction of display mode,in most of the virtual reality systems with multiple people in the same physical space,the program renders the scene based on the position and perspective of the one user,so that other users just see the same scene,resulting in vision disorder.Methods To improve experience of multi-user co-located collaboration,in this study,we propose a fire drill system supporting co-located collaboration,in which three co-located users can collaborate to complete the virtual firefighting mission.Firstly,with multi-view stereoscopic projective display technology and ultra wideband(UWB)technology,co-located users can roam independently and watch virtual scenes through the correct perspective view based on their own position by wearing dedicated shutter glasses,thus carrying out different virtual tasks,which improves the flexibility of co-located collaboration.Secondly,we design simulated firefighting water-gun using the micro-electromechanical system sensor,through which users can interact with virtual environment,and thus provide a better interactive experience.Finally,we develop a workbench including a holographic display module and multi touch operation module for virtual scene assembly and virtual environment control.Results The controller can use the workbench to adjust the virtual layout in real time,and control the virtual task process to increase the flexibility and playability of system.Conclusions Our work can be employed in a wide range of related virtual reality applications.

Liquid-phase synthesis of Li_(2)S and Li_(3)PS_(4) with lithium-based organic solutions

Sulfide solid electrolytes are widely regarded as one of the most promising technical routes to realize all-solid-state batteries(ASSBs)due to their high ionic conductivity and favorable deformability.However,the relatively high price of the crucial starting material,Li_(2)S,results in high costs of sulfide solid electrolytes,limiting their practical application in ASSBs.To solve this problem,we develop a new synthesis route of Li_(2)S via liquid-phase synthesis method,employing lithium and biphenyl in 1,2-dimethoxyethane(DME)ether solvent to form a lithium solution as the lithium precursor.Because of the comparatively strong reducibility of the lithium solution,its reaction with sulfur proceeds effectively even at room temperature.This new synthesis route of Li_(2)S starts with cheap precursors of lithium,sulfur,biphenyl and DME solvent,and the only remaining byproduct(DME solution of biphenyl)after the collection of Li_(2)S product can be recycled and reused.Besides,the reaction can proceed effectively at room temperature with mild condition,reducing energy cost to a great extent.The as-synthesized Li_(2)S owns uniform and extremely small particle size,proved to be feasible in synthesizing sulfide solid electrolytes(such as the solid-state synthesis of Li_(6)PS_(5)C_(l)).Spontaneously,this lithium solution can be directly employed in the synthesis of Li_(3)PS_(4) solid electrolytes via liquid-phase synthesis method,in which the centrifugation and heat treatment processes of Li_(2)S are not necessary,providing simplified production process.The as-synthesized Li_(3)PS_(4) exhibits typical Li+conductivity of 1.85×10^(-4) S·cm^(-1) at 30℃.

Insights into the synergistic promotion of spin polarization over C_(3)N_(5.4) for enhancing cooperative hydrogen evolution and benzylamine oxidation coupling

Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric constants.Regulating spin-polarized electrons is regarded as an attractive strategy,but often confined to the d-orbital elements.Here,the nonmetal P and N elements co-mediated the spin polarization of carbon nitrides(PCN)have been elaborately designed.The optimized PCN-3 shows an outstanding hydrogen production(22.2 mmol·g^(-1)·h^(-1))coupled with selective benzylamine oxidation without using any solvent and cocatalysts,which is 200 times of original C_(3)N_(4)and superior to the photocatalysts has been reported to date.Experimental and theoretical results verified that the spin-orbital coupling of N 2p and P 2p remarkably increased the parallel spin states of charge and reduced the formation of singlet excitons to accelerate exciton dissociation in carbon nitride.In addition,charge separation and surface catalysis can be significantly enhanced by the electron spin polarization of carbon nitride with the parallel arrangement,huge built-in electric field and disturbed electronic structure.Our finding deepens the insight into the charge separation and exciton dissociation in spin polarization,and offers new tactics to develop high-efficiency catalysts.