The miniaturization and high integration of devices demand significant thermal management materials.Current technologies for the thermal management of electronics show some limitations in the case of multiple chip arr...The miniaturization and high integration of devices demand significant thermal management materials.Current technologies for the thermal management of electronics show some limitations in the case of multiple chip arrays.A device in multiple chip array is affected by heat from adjacent devices,along with thermal conductive composite.To address this problem,we present a nano composite of aligned boron nitride(BN)nanosheet islands with porous polydimethylsiloxane(PDMS)foam to have mechanical stability and non-thermal interference.The islands of tetrahedrally-structured BN in the composite have a high thermal conductivity of 1.219 W·m^(-1)·K^(-1) in the through-plane direction(11.234W·m^(-1)·K^(-1)in the in-plane direction)with 16 wt.%loading of BN.On the other hand,porous PDMS foam has a low thermal conductivity of 0.0328W·m^(-1)·K^(-1) in the through-plane direction at 70%porosity.Heat pathways are then formed only in the structured BN islands of the composite.The porous PDMS foam can be applied as a thermal barrier between structured BN islands to inhibit thermal interference in multiple device arrays.Furthermore,this composite can maintain selective thermal dissipation performance with 70%tensile strain.Another beauty of the work is that it could have guided heat dissipation by assembling of multiple layers which have high vertical thermal conductive islands,while inhibiting thermal interference.The selective heat dissipating composite can be applied as a heatsink for multiple chip arrays electronics.展开更多
The shuttle effect of lithium polysulfides and the uncontrollable deposition of lithium sulfides(Li_(2)S)severely hinder the realization of high-performance lithium-sulfur(Li-S)batteries.Herein,we fabricated a carbon ...The shuttle effect of lithium polysulfides and the uncontrollable deposition of lithium sulfides(Li_(2)S)severely hinder the realization of high-performance lithium-sulfur(Li-S)batteries.Herein,we fabricated a carbon cloth(CC)-based self-supported interlayer(denoted as Co_(4)S_(3)/C@CC),which is covered with Co_(4)S_(3)-embedded porous carbon nanoarrays through a facile two-step method with cobalt-based metal-organic framework(Co-MOF)nanosheets as the template.The interconnected carbon network and the polar Co_(4)S_(3)nanoparticles in the Co_(4)S_(3)/C@CC interlayer not only effectively suppress the polysulfide shuttle,but also significantly facilitate the lithium ion(Li^(+))conduction with a considerable Li^(+)transference number of 0.86.Besides,the rich interfaces between the polar Co_(4)S_(3)nanoparticles and the conductive carbon substrate serve as reaction sites to accelerate the polysulfide conversion and guide the flower-like growth of Li_(2)S,which ultimately mitigates the interlayer surface passivation and improves the sulfur utilization.Therefore,the Li-S batteries with the Co_(4)S_(3)/C@CC interlayer deliver an excellent rate capacity(368.7 mA h g^(−1)at 10 C),a stable cycling performance(a low fading rate of 0.045%per cycle over 1400 cycles at 2.0 C),and a high initial areal capacity(4.83 mA h cm^(−2)at 0.2 C under a sulfur loading of 4.6 mg cm^(−2)).This work provides a perspective on the self-supported catalytic interlayer for the selective Li^(+)conduction and Li_(2)S regulation toward high-performance Li-S batteries.展开更多
基金supported by a National Research Foundation of Korea(NRF)grant,funded by the Korean government(MSIT)(NRF-2020M3H4A1A02084898 and NRF-2019M3C7A1032076)the Technology Innovation Program(20013794,Center for Composite Materials and Concurrent Design)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘The miniaturization and high integration of devices demand significant thermal management materials.Current technologies for the thermal management of electronics show some limitations in the case of multiple chip arrays.A device in multiple chip array is affected by heat from adjacent devices,along with thermal conductive composite.To address this problem,we present a nano composite of aligned boron nitride(BN)nanosheet islands with porous polydimethylsiloxane(PDMS)foam to have mechanical stability and non-thermal interference.The islands of tetrahedrally-structured BN in the composite have a high thermal conductivity of 1.219 W·m^(-1)·K^(-1) in the through-plane direction(11.234W·m^(-1)·K^(-1)in the in-plane direction)with 16 wt.%loading of BN.On the other hand,porous PDMS foam has a low thermal conductivity of 0.0328W·m^(-1)·K^(-1) in the through-plane direction at 70%porosity.Heat pathways are then formed only in the structured BN islands of the composite.The porous PDMS foam can be applied as a thermal barrier between structured BN islands to inhibit thermal interference in multiple device arrays.Furthermore,this composite can maintain selective thermal dissipation performance with 70%tensile strain.Another beauty of the work is that it could have guided heat dissipation by assembling of multiple layers which have high vertical thermal conductive islands,while inhibiting thermal interference.The selective heat dissipating composite can be applied as a heatsink for multiple chip arrays electronics.
基金financially supported by the National Natural Science Foundation of China(51871188,51931006)。
文摘The shuttle effect of lithium polysulfides and the uncontrollable deposition of lithium sulfides(Li_(2)S)severely hinder the realization of high-performance lithium-sulfur(Li-S)batteries.Herein,we fabricated a carbon cloth(CC)-based self-supported interlayer(denoted as Co_(4)S_(3)/C@CC),which is covered with Co_(4)S_(3)-embedded porous carbon nanoarrays through a facile two-step method with cobalt-based metal-organic framework(Co-MOF)nanosheets as the template.The interconnected carbon network and the polar Co_(4)S_(3)nanoparticles in the Co_(4)S_(3)/C@CC interlayer not only effectively suppress the polysulfide shuttle,but also significantly facilitate the lithium ion(Li^(+))conduction with a considerable Li^(+)transference number of 0.86.Besides,the rich interfaces between the polar Co_(4)S_(3)nanoparticles and the conductive carbon substrate serve as reaction sites to accelerate the polysulfide conversion and guide the flower-like growth of Li_(2)S,which ultimately mitigates the interlayer surface passivation and improves the sulfur utilization.Therefore,the Li-S batteries with the Co_(4)S_(3)/C@CC interlayer deliver an excellent rate capacity(368.7 mA h g^(−1)at 10 C),a stable cycling performance(a low fading rate of 0.045%per cycle over 1400 cycles at 2.0 C),and a high initial areal capacity(4.83 mA h cm^(−2)at 0.2 C under a sulfur loading of 4.6 mg cm^(−2)).This work provides a perspective on the self-supported catalytic interlayer for the selective Li^(+)conduction and Li_(2)S regulation toward high-performance Li-S batteries.
