Structural and electronic features of binary Li₂S-P₂S₅ glasses.
Structural and electronic features of binary Li₂S-P₂S₅ glasses.
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DOI：
10.1038/srep21302
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发表时间：
2016-02-19
影响因子：
4.6
通讯作者：
Ogumi Z
中科院分区：
文献类型：
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作者：
Ohara K;Mitsui A;Mori M;Onodera Y;Shiotani S;Koyama Y;Orikasa Y;Murakami M;Shimoda K;Mori K;Fukunaga T;Arai H;Uchimoto Y;Ogumi Z
利用同步辐射X射线衍射、中子衍射和拉曼光谱数据，采用密度泛函理论（DFT）和反向蒙特卡罗（RMC）相结合的方法，对用作固体电解质的Li 2S-P2 S5二元玻璃的原子和电子结构进行了模拟.基于拉曼光谱结果的PSx多面体阴离子的比例反映在67 Li 2S-33 P2 S5、70 Li 2S-30 P2 S5和75 Li 2S-25 P2 S5玻璃的玻璃结构中，并且合理的结构代表了它们周围的锂离子分布。结果表明，当Li 2S含量较高时，PSx多面体和LiSy多面体的边共享率增大，而PSx多面体周围的自由体积减小.结果表明，PSx多面体表面附近的Li+离子明显受到阴离子极化的影响。DFT/RMC模型的电子结构表明，P离子和桥硫（BS）离子之间的电子转移削弱了P2 S7阴离子中P离子的正电荷。P2 S7阴离子的弱静电斥力使其比PS4和P2 S6阴离子更强地吸引Li+离子，并抑制锂离子导电。因此，在没有P离子和BS离子之间的电子转移的情况下，PSx和LiSy多面体之间的边缘共享的控制预期促进上述固体电解质中的锂离子传导。
The atomic and electronic structures of binary Li2S-P2S5 glasses used as solid electrolytes are modeled by a combination of density functional theory (DFT) and reverse Monte Carlo (RMC) simulation using synchrotron X-ray diffraction, neutron diffraction, and Raman spectroscopy data. The ratio of PSx polyhedral anions based on the Raman spectroscopic results is reflected in the glassy structures of the 67Li2S-33P2S5, 70Li2S-30P2S5, and 75Li2S-25P2S5 glasses, and the plausible structures represent the lithium ion distributions around them. It is found that the edge sharing between PSx and LiSy polyhedra increases at a high Li2S content, and the free volume around PSx polyhedra decreases. It is conjectured that Li+ ions around the face of PSx polyhedra are clearly affected by the polarization of anions. The electronic structure of the DFT/RMC model suggests that the electron transfer between the P ion and the bridging sulfur (BS) ion weakens the positive charge of the P ion in the P2S7 anions. The P2S7 anions of the weak electrostatic repulsion would causes it to more strongly attract Li+ ions than the PS4 and P2S6 anions, and suppress the lithium ionic conduction. Thus, the control of the edge sharing between PSx and LiSy polyhedra without the electron transfer between the P ion and the BS ion is expected to facilitate lithium ionic conduction in the above solid electrolytes.