Ti_(3)C_(2)T_(x) nanosheets have attracted significant attention for their potential in electromagnetic wave absorption(EWA).However,their inherent self-stacking and exorbitant electrical conductivity inevitably lead ...Ti_(3)C_(2)T_(x) nanosheets have attracted significant attention for their potential in electromagnetic wave absorption(EWA).However,their inherent self-stacking and exorbitant electrical conductivity inevitably lead to serious impedance mismatch,restricting their EWA application.Therefore,the optimization of impedance matching becomes crucial.In this work,we developed polymethyl methacrylate(PMMA)@Ti_(3)C_(2)T_(x)@SiO_(2) composites with a sandwich-like core–shell structure by coating SiO_(2) on PMMA@Ti_(3)C_(2)T_(x).The results demonstrate that the superiority of the SiO_(2) layer in combination with PMMA@Ti_(3)C_(2)T_(x),outperforming other relative graded distribution structures and meeting the requirements of EWA equipment.The resulting PMMA@Ti_(3)C_(2)T_(x)@SiO_(2) composites achieved a minimum reflection loss of-58.08 dB with a thickness of 1.9 mm,and an effective absorption bandwidth of 2.88 GHz.Mechanism analysis revealed that the structural design of SiO_(2) layer not only optimized impedance matching,but also synergistically enhanced multiple loss mechanisms such as interfacial polarization and dipolar polarization.Therefore,this work provides valuable insights for the future preparation of high-performance electromagnetic wave absorbing Ti_(3)C_(2)T_(x)-based composites.展开更多
Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in...Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in-situ ionic ring-opening polymerization of 1,3-dioxolane(DOL) monomers in SiO_(2) nanofiber membrane(PDOL-SiO_(2)) for lithium metal batteries.The oxygen atoms of PDOL together with Si-O of SiO_(2) construct a more efficient channel for Li^(+) migration.Consequently,the lithium ion transference number(t_(Li^(+)) and ionic conductivity(σ) at 30℃ of PDOL-SiO_(2) are 0.80 and 1.68×10^(-4)S/cm separately.PDOL-SiO_(2) manifests the electrochemical decomposition potentials of 4.90 V.At 0.5 mA/cm^(2),Li|PDOL-SiO_(2) |Li cell shows a steady cycling performance for nearly 1400 h.LFP|PDOL-SiO_(2) |Li battery can steadily cycle at 0.5 C with a capacity retention rate of 89% after 200 cycles.While cycling at 2 C,the capacity retention rate can maintain at 78% after 300 cycles.This contribution provides a innovative strategy for accelerating Li^(+)transportation via designing PDOL molecular chains throughout the SiO_(2) nanofiber framework,which is crucial for high-energy-density LMBs.展开更多
基金supported by the National Natural Science Foundation of China(No.U2004177)Henan Province Key Research Project for Higher Education Institutions(No.23B430017)+1 种基金the Outstanding Youth Fund of Henan Province(No.212300410081)the Science and Technology Innovation Talents in Universities of Henan Province(No.22HASTIT001).
文摘Ti_(3)C_(2)T_(x) nanosheets have attracted significant attention for their potential in electromagnetic wave absorption(EWA).However,their inherent self-stacking and exorbitant electrical conductivity inevitably lead to serious impedance mismatch,restricting their EWA application.Therefore,the optimization of impedance matching becomes crucial.In this work,we developed polymethyl methacrylate(PMMA)@Ti_(3)C_(2)T_(x)@SiO_(2) composites with a sandwich-like core–shell structure by coating SiO_(2) on PMMA@Ti_(3)C_(2)T_(x).The results demonstrate that the superiority of the SiO_(2) layer in combination with PMMA@Ti_(3)C_(2)T_(x),outperforming other relative graded distribution structures and meeting the requirements of EWA equipment.The resulting PMMA@Ti_(3)C_(2)T_(x)@SiO_(2) composites achieved a minimum reflection loss of-58.08 dB with a thickness of 1.9 mm,and an effective absorption bandwidth of 2.88 GHz.Mechanism analysis revealed that the structural design of SiO_(2) layer not only optimized impedance matching,but also synergistically enhanced multiple loss mechanisms such as interfacial polarization and dipolar polarization.Therefore,this work provides valuable insights for the future preparation of high-performance electromagnetic wave absorbing Ti_(3)C_(2)T_(x)-based composites.
基金supported by the Department of Science and Technology of Zhuhai City(No.ZH22017001200059PWC)the Department of Science and Technology of Guangdong Province,China(No.2019A050510043)。
文摘Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in-situ ionic ring-opening polymerization of 1,3-dioxolane(DOL) monomers in SiO_(2) nanofiber membrane(PDOL-SiO_(2)) for lithium metal batteries.The oxygen atoms of PDOL together with Si-O of SiO_(2) construct a more efficient channel for Li^(+) migration.Consequently,the lithium ion transference number(t_(Li^(+)) and ionic conductivity(σ) at 30℃ of PDOL-SiO_(2) are 0.80 and 1.68×10^(-4)S/cm separately.PDOL-SiO_(2) manifests the electrochemical decomposition potentials of 4.90 V.At 0.5 mA/cm^(2),Li|PDOL-SiO_(2) |Li cell shows a steady cycling performance for nearly 1400 h.LFP|PDOL-SiO_(2) |Li battery can steadily cycle at 0.5 C with a capacity retention rate of 89% after 200 cycles.While cycling at 2 C,the capacity retention rate can maintain at 78% after 300 cycles.This contribution provides a innovative strategy for accelerating Li^(+)transportation via designing PDOL molecular chains throughout the SiO_(2) nanofiber framework,which is crucial for high-energy-density LMBs.
