Dendrite growth in lithium-ion batteries may bring thermal run-away especially at high current densities,which remains the major bottleneck to implement safe and fast charging for portable electronic devices or electr...Dendrite growth in lithium-ion batteries may bring thermal run-away especially at high current densities,which remains the major bottleneck to implement safe and fast charging for portable electronic devices or electronical vehicles.Designing dendrite inhibition separators with proper pore size is considered to be one of the most promising strategies to guarantee the battery safety.However,due to the impossible observation of lithium-ion distribution under separator by experiments,the underlying dendrite inhibition mechanism is still not fully understood.Here,we apply the phase-field model,which takes the separator phase into account to construct the electrochemical system total free energy,to study the ion re-distribution behavior of porous separator and understand the pore size inhibition effect on lithium dendrite.The numerical results indicate that separator with smaller pore size is beneficial to smoother electrodeposition,since the lithium-ion concentration on the electrode surface is more uniform under denser separator pores,when their sizes is larger than the critical nucleus.The proposed model could capture the physicochemical process of electrodeposition under multiphase structures,so it could also be used to explore dendrite growth under composite electrodes and composite solid electrolytes.展开更多
To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_(2.5) and size-segregated aerosol particles were collected daily during fall at an urban site ...To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_(2.5) and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju,Korea.During the study period,the total concentration of secondary ionic species(SIS) contributed an average of 43.9% to the PM_(2.5) ,whereas the contribution of SIS to the PM_(2.5) during the haze period was 62.3%.The NO_3 and SO^(2-)_4 concentrations in PM_(2.5) during the haze period were highly elevated,being 13.4 and 5.0 times higher than those during non-haze period,respectively.The PM,NO^-_3,SO^(2-)_4,oxalate,water-soluble organic carbon(WSOC),and humic-like substances(HULIS) had tri-modal size distributions peaks at 0.32,1.0,and 5.2 μm during the non-haze and haze periods.However,during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm,while on October 21 when the heaviest haze event occurred,they had predominant droplet mode size distributions peaking at 1.00 μm.Moreover,strong correlations of WSOC and HULIS with SO^(2-)_4,oxalate,and K+at particle sizes of 〈 1.8 μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations.It was found that the factors affecting haze formation could be the local stable synoptic conditions,including the weak surface winds and high surface pressures,the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula,as well as the locally emitted and produced aerosol particles.展开更多
基金the National Natural Science Foundation of China(Nos.52102280,U2030206,11874254,51622207)Shanghai Pujiang Program(No.2019PJD016)+2 种基金Foundation of China Academy of Engineering Physics-Key Laboratory of Neutron Physics(No.2019BB07)Scientific Research Project of Zhijiang Laboratory(No.2021PE0AC02)funding from King Abdullah University of Science and Technology(KAUST)。
文摘Dendrite growth in lithium-ion batteries may bring thermal run-away especially at high current densities,which remains the major bottleneck to implement safe and fast charging for portable electronic devices or electronical vehicles.Designing dendrite inhibition separators with proper pore size is considered to be one of the most promising strategies to guarantee the battery safety.However,due to the impossible observation of lithium-ion distribution under separator by experiments,the underlying dendrite inhibition mechanism is still not fully understood.Here,we apply the phase-field model,which takes the separator phase into account to construct the electrochemical system total free energy,to study the ion re-distribution behavior of porous separator and understand the pore size inhibition effect on lithium dendrite.The numerical results indicate that separator with smaller pore size is beneficial to smoother electrodeposition,since the lithium-ion concentration on the electrode surface is more uniform under denser separator pores,when their sizes is larger than the critical nucleus.The proposed model could capture the physicochemical process of electrodeposition under multiphase structures,so it could also be used to explore dendrite growth under composite electrodes and composite solid electrolytes.
基金supported by the Basic Science Research Programs through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(NRF2014R1A1A4A01003896)the support from the BK21 Plus program through the NRF funded by the MOE
文摘To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_(2.5) and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju,Korea.During the study period,the total concentration of secondary ionic species(SIS) contributed an average of 43.9% to the PM_(2.5) ,whereas the contribution of SIS to the PM_(2.5) during the haze period was 62.3%.The NO_3 and SO^(2-)_4 concentrations in PM_(2.5) during the haze period were highly elevated,being 13.4 and 5.0 times higher than those during non-haze period,respectively.The PM,NO^-_3,SO^(2-)_4,oxalate,water-soluble organic carbon(WSOC),and humic-like substances(HULIS) had tri-modal size distributions peaks at 0.32,1.0,and 5.2 μm during the non-haze and haze periods.However,during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm,while on October 21 when the heaviest haze event occurred,they had predominant droplet mode size distributions peaking at 1.00 μm.Moreover,strong correlations of WSOC and HULIS with SO^(2-)_4,oxalate,and K+at particle sizes of 〈 1.8 μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations.It was found that the factors affecting haze formation could be the local stable synoptic conditions,including the weak surface winds and high surface pressures,the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula,as well as the locally emitted and produced aerosol particles.