Competitive network modification in non-oxide chalcogenide glasses structural and motional properties of glasses in the system Li2S-P2S5-B2S3 studied by multinuclear NMR techniques
Competitive network modification in non-oxide chalcogenide glasses structural and motional properties of glasses in the system Li2S-P2S5-B2S3 studied by multinuclear NMR techniques
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非氧化物硫系玻璃的竞争网络改性通过多核NMR技术研究Li2S-P2S5-B2S3体系中玻璃的结构和运动性质
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
H. Eckert
中科院分区：
文献类型：
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作者：
Z. Zhang;J. Kennedy;J. Thompson;S. Anderson;D. Lathrop;H. Eckert
基于多于一种网络形成剂物质的非氧化物硫属玻璃对于作为电池中的固体电解质的应用具有某些优势。为了阐明竞争玻璃形成对离子导电硫系玻璃结构和运动性质的影响，采用DSC、电导率和6Li、7 Li、31 P和11B固体核磁共振技术对（Li 2S）0.67[（B2 S3）1-y（P2 S5）y]0.33系统进行了全面表征.所获得的数据提供了第一个系统的表征的共形成物的效果在硫系玻璃系统。y =0.3和0.9 ≤ y ≤ 1.0时形成均质玻璃样品，0 ≤ y ≤ 0.2时形成微相分离玻璃。共形成物的存在导致电导率的增加和活化能的降低，与二元系统（Li 2S-B2 S3或Li 2S-P2 S5）相比，但仅在形成均质玻璃的情况下。NMR数据，结合系统的DSC和NMR研究的二元系统（Li 2S）x（B2 S3）1-x（0.50 μ x μ 0.75）和（Li2S）x（P2S5）1−x（0.50 × 10.70），得出以下结论：1）~（11）B MAS-NMR非常适合于三配位和四配位硼原子的定量;在二元玻璃中，四倍硼（N4）的含量随Li_2S/B_2S_3比值的减小而增大，在三元玻璃中，N4随y的增大而增大。2）二元玻璃的31 P MAS-NMR谱区分三种不同的磷微环境，分别归属于偏磷酸盐、焦磷酸盐和正磷酸盐物种的硫化物类似物。这些结果表明，最初开发的氧化物玻璃的网络修改模型的适用性。对于三元玻璃，具有低磷含量的玻璃的DSC和NMR数据与相分离模型一致，所述相分离模型涉及含有所有磷组分的富锂硫代硼酸盐玻璃和含有四重硼原子的锂含量较低的玻璃相。除了结构研究外，还用7 Li自旋-自旋弛豫时间（T2）来表征Li原子的迁移率。Li运动的活化能，由温度依赖的T2测量和分析，使用BPP理论，从电导率测量的2-3倍，可能反映了该理论的不适用性的锂扩散过程中确定的不同。
Non-oxide chalcogenide glasses based on more than one network former species have certain advantages for applications as solid electrolytes in batteries. To elucidate the influence of competitive glass-formation on the structural and motional properties of ionically conductive chalcogenide glasses, the system (Li2S)0.67[(B2S3)1−y(P2S5)y]0.33 has been characterized comprehensively by DSC, electrical conductivity and6Li,7Li,31P, and11B solid state NMR techniques. The data obtained provide the first systematic characterization of the coformer effect in a chalcogenide glass system. Homogeneous glassy samples are formed fory=0.3 and 0.9≦y≦1.0, and microphase separated glasses for 0≦y≦0.2. The presence of a coformer leads to an increase in the electrical conductivity and a decrease of the activation energy, as compared to either binary system (Li2S-B2S3 or Li2S-P2S5), but only if homogeneous glasses are formed. The NMR data, in conjunction with systematic DSC and NMR studies of the binary systems (Li2S)x(B2S3)1−x (0.50≦x≦0.75) and (Li2S)x(P2S5)1−x (0.50≦x≦0.70), lead to the following conclusions: 1)11B MAS-NMR is well-suited to quantitate the amounts of three- and four coordinated boron atoms; in the binary glasses, the fraction of four-fold boron (N4) increases with decreasing Li2S/B2S3 ratio; in the ternary glasses N4 increases with increasingy. 2)31P MAS-NMR spectra of the binary glasses discriminate between three different phosphorus microenvironments, assigned to sulfide-analogs of metaphosphate, pyrophosphate, and orthophosphate species, respectively. These results suggest the applicability of network modification models originally developed for oxide glasses. For the ternary glasses, the DSC and NMR data of glasses with low phosphorus contents are consistent with a phase separation model involving a Li-rich thioborate glass that contains all of the phosphorus component and a glass phase less rich in lithium containing the four-fold boron atoms. In addition to the structural studies, the7Li spin-spin relaxation times (T2) are used to characterize the mobility of the Li atoms. The activation energy of Li motion, determined from temperature dependentT2 measurements and analyzed by using BPP theory differs from that determined from conductivity measurements by a factor of 2–3, possibly reflecting the inapplicability of this theory to the lithium diffusion process.