物理化学学报2020，Vol.36Issue(11)：82-89,8.DOI:10.3866/PKU.WHXB202001048
利用固态核磁共振研究100LiO1/2-(100-x)PO5/2-xTeO2快离子导电玻璃的结构
Structure Investigations on 100LiO1/2-(100-x)PO5/2-xTeO2 Fast Ionic Conducting Glasses Using Solid-State Nuclear Magnetic Resonance Spectroscopy
摘要
Abstract
Modified phosphate glasses can be used in all-solid-state batteries as solid electrolytes and cathodes due to their high ionic conductivity.The properties of fast ionic conducting glasses are strongly related to the structure of the glass networks.However,most previous works have focused on improving the ionic conductivity of such glasses by composition adjustments,while structural studies are scant.Structural investigations are essential to understand the composition dependence of the glass structure,which is valuable for improving the ionic conductivity and developing new ionic conducting glasses.In this work,phosphate ionic conducting glasses with compositions of 100LiO1/2-(100-x)PO5/2-xTeO2 (x =0,10,20,25,30) were synthesized,and their structures were investigated using Raman and solid-state nuclear magnetic resonance (SSNMR) spectroscopy.When x =0,Raman and 31P magic angle spinning (MAS) NMR spectra showed that most of the phosphorus species were Q(2)0Te species,while the concentration of Q(1)0Te species was negligible.Q(n)mTe represents the phosphorus species withn bridging oxygen atoms (the oxygen atoms in P-O-P and P-O-Te linkages are both considered to be bridging oxygen atoms),and m Te atoms are connected to this[PO4]tetrahedron.When PO5/2 is substituted with TeO2,long P-O-P chains are broken into short chains,and Q(2)0Te species gradually transform into Q(2)1Te and Q(1)0Te species.Two-dimensional (2D) refocused incredible natural abundance double quantum transfer experiment (INADEQUATE) spectra proved that no isolated phosphorus species existed in the glasses;Q(2)0Te,Q(2)1re,and Q(1)Te species were connected with each other through P-O-P linkages.Three-and four-coordinated Te were observed in the static 125Te wideband uniform-rate smooth truncation quadrupolar Carr-Purcell-Meiboom-Gill (WURST-QCPMG) spectra.When the concentration of TeO2 was low,four-coordinated Te was dominant.However,with the increase in TeO2,the proportion of three-coordinated Te gradually increased,while that of four-coordinated Te decreased.The experimental contents of P-O-P,P-O-Te,and Te-O-Te linkages in these glasses were calculated from the deconvolutions of 31p and 125Te NMR spectra.Then,the experimental contents were compared with the theoretical contents calculated according to a random distribution model.It was found that the experimental contents of homonuclear P-O-P and Te-O-Te linkages were slightly higher than their corresponding theoretical values,while the experimental content of heteronuclear P-O-Te was slightly lower than the theoretical value.These results indicated a weak priority for homonuclear connectivities.In this glass system,Li+ ions preferred to stay around[PO4]tetrahedrons rather than tellurium oxygen polyhedrons.However,a small number of Li+ ions still interacted with tellurium oxygen polyhedrons to form[TeO3]units.During the substitution of PO5/2 by TeO2,the fractions of bridging oxygen atoms in these glasses were almost unchanged,resulting in a slight change in the glass transition temperature.This work provides a comprehensive description of glass networks,depending on their compositions,which could be valuable for improving the ionic conductivity and for designing new fast ionic conducting glasses through structural modifications.关键词
磷碲酸盐玻璃/固态核磁共振/快离子导体/玻璃结构/拉曼光谱Key words
Phosphotellurite glass/Solid-state NMR/Fast ionic conductor/Glass structure/Raman spectrum分类
化学化工引用本文复制引用
张宗辉,任进军,胡丽丽..利用固态核磁共振研究100LiO1/2-(100-x)PO5/2-xTeO2快离子导电玻璃的结构[J].物理化学学报,2020,36(11):82-89,8.基金项目
The project was supported by the National Natural Science Foundation of China (61675218) and the 100 Talents Program of Chinese Academy of Sciences.国家自然科学基金(61675218)和中国科学院百人计划资助项目 （61675218）
