为提高层合板损伤检测的准确性与灵敏度,基于聚偏二氟乙烯(polyvinylidene fluoride,PVDF)梳状换能器激发的零群速度(zero group velocity,ZGV)Lamb波,提出了一种层合板损伤的检测方法。采用二维时域有限元方法,研究了PVDF梳状换能器对...为提高层合板损伤检测的准确性与灵敏度,基于聚偏二氟乙烯(polyvinylidene fluoride,PVDF)梳状换能器激发的零群速度(zero group velocity,ZGV)Lamb波,提出了一种层合板损伤的检测方法。采用二维时域有限元方法,研究了PVDF梳状换能器对零群速度Lamb波的激励,通过改变层合板中铝层杨氏模量来表征不同的损伤程度,分析了PVDF梳状换能器电压响应特性与层合板损伤程度之间的关系。结果表明:采用PVDF梳状换能器能够有效激励零群速度Lamb波,并获得层合板内部的状态信息。随着损伤程度的增加,PVDF梳状换能器响应的零群速度共振峰频域幅值随着铝层杨氏模量的减小而显著减少,进而灵敏地评价层合板损伤变化。研究结果说明优化设计的PVDF梳状换能器在零群速度Lamb波的激发与接收性能上都具有优越性,能够有效检测层合板损伤情况。展开更多
Poly(ethylene oxide)(PEO)and Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)-based composite polymer electrolytes(CPEs)are considered one of the most promising solid electrolyte systems.However,agglomeration of LLZTO w...Poly(ethylene oxide)(PEO)and Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)-based composite polymer electrolytes(CPEs)are considered one of the most promising solid electrolyte systems.However,agglomeration of LLZTO within PEO and lack of Li^(+)channels result in poor electrochemical properties.Herein,a functional supramolecular combination(CD-TFSI)consisting of activeβ-cyclodextrin(CD)supramolecular with self-assembled LiTFSI salt is selected as an interface modifier to coat LLZTO fillers.Benefiting from vast H-bonds formed betweenβ-CD and PEO matrix and/or LLZTO,homogeneous dispersion and tight interface contact are obtained.Moreover,^(6)Li NMR spectra confirm a new Li^(+)transmission pathway from PEO matrix to LLZTO ceramic then to PEO matrix in the as-prepared PEO/LLZTO@CD-TFSI CPEs due to the typical cavity structure ofβ-CD.As a proof,the conductivity is increased from 5.3×10^(-4)S cm^(-1)to 8.7×10^(-4)S cm^(-1)at 60℃,the Li^(+)transference number is enhanced from 0.38 to 0.48,and the electrochemical stability window is extended to 5.1 V versus Li/Li^(+).Li‖LiFePO_(4)CR2032 coin full cells and pouch cells prove the practical application of the as-prepared PEO/LLZTO@CD-TFSI CPEs.This work offers a new strategy of interface modifying LLZTO fillers with functional supramolecular combination to optimize PEO/LLZTO CPEs for solid lithium batteries.展开更多
文摘为提高层合板损伤检测的准确性与灵敏度,基于聚偏二氟乙烯(polyvinylidene fluoride,PVDF)梳状换能器激发的零群速度(zero group velocity,ZGV)Lamb波,提出了一种层合板损伤的检测方法。采用二维时域有限元方法,研究了PVDF梳状换能器对零群速度Lamb波的激励,通过改变层合板中铝层杨氏模量来表征不同的损伤程度,分析了PVDF梳状换能器电压响应特性与层合板损伤程度之间的关系。结果表明:采用PVDF梳状换能器能够有效激励零群速度Lamb波,并获得层合板内部的状态信息。随着损伤程度的增加,PVDF梳状换能器响应的零群速度共振峰频域幅值随着铝层杨氏模量的减小而显著减少,进而灵敏地评价层合板损伤变化。研究结果说明优化设计的PVDF梳状换能器在零群速度Lamb波的激发与接收性能上都具有优越性,能够有效检测层合板损伤情况。
基金the financial support of the National Natural Science Foundation of China(Nos.21773167,51972220)the National Key Research and Development Program of China(No.2021YFE0107200)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.20KJA480003)the Key R&D Project funded by Department of Science and Technology of Jiangsu Province(No.BE2020003)
文摘Poly(ethylene oxide)(PEO)and Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)-based composite polymer electrolytes(CPEs)are considered one of the most promising solid electrolyte systems.However,agglomeration of LLZTO within PEO and lack of Li^(+)channels result in poor electrochemical properties.Herein,a functional supramolecular combination(CD-TFSI)consisting of activeβ-cyclodextrin(CD)supramolecular with self-assembled LiTFSI salt is selected as an interface modifier to coat LLZTO fillers.Benefiting from vast H-bonds formed betweenβ-CD and PEO matrix and/or LLZTO,homogeneous dispersion and tight interface contact are obtained.Moreover,^(6)Li NMR spectra confirm a new Li^(+)transmission pathway from PEO matrix to LLZTO ceramic then to PEO matrix in the as-prepared PEO/LLZTO@CD-TFSI CPEs due to the typical cavity structure ofβ-CD.As a proof,the conductivity is increased from 5.3×10^(-4)S cm^(-1)to 8.7×10^(-4)S cm^(-1)at 60℃,the Li^(+)transference number is enhanced from 0.38 to 0.48,and the electrochemical stability window is extended to 5.1 V versus Li/Li^(+).Li‖LiFePO_(4)CR2032 coin full cells and pouch cells prove the practical application of the as-prepared PEO/LLZTO@CD-TFSI CPEs.This work offers a new strategy of interface modifying LLZTO fillers with functional supramolecular combination to optimize PEO/LLZTO CPEs for solid lithium batteries.
