Structural origin of massive improvement in Li-ion conductivity on transition from (Li2S)5(GeS2)(P2S5) glass to Li10GeP2S12 crystal
Structural origin of massive improvement in Li-ion conductivity on transition from (Li2S)5(GeS2)(P2S5) glass to Li10GeP2S12 crystal
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DOI：
10.1016/j.ssi.2017.01.023
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发表时间：
2017-03-01
影响因子：
3.2
通讯作者：
Fukunaga, Toshiharu
中科院分区：
文献类型：
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作者：
Mori, Kazuhiro;Kasai, Takuya;Fukunaga, Toshiharu
对机械合金化制备的锂离子导体（Li_2S）（_5）（GeS_2）（P_2S_5）玻璃进行了同步辐射X射线衍射和飞行时间中子衍射实验。结合反向蒙特卡罗（RMC）模拟和键价和（BVS）方法，研究了Li离子在（Li 2S）（5）（GeS 2）（P2 S5）玻璃中的三维结构和导电路径.表征了电化学性质;该材料在300 I下的电导率σ（300）（K）为1.5 × 10（-5）S/cm（活化能E-a为55 kJ/mol）。此外，通过对（Li_2S）_（5）（GeS_2）（P_2S_5）玻璃在803 K下进行时效处理，可以得到最先进的锂离子导体Li_（10）GeP_2S_（12）晶体（σ（300 K）= 1.2 × 10 ~（-2）S/cm，E-a = 24 kJ/mot）。通过比较Li离子在（Li_2S）（5）（GeS_2）（P_2S_5）玻璃和Li_（10）GeP_2S_（12）晶体中的导电路径，发现Li离子的最大BV失配值，用于（Li 2S）（5）（GeS 2）（P2 S5）玻璃（竖线Δ V（Li）竖线（max）= 0.13）显著大于Li 10 GeP 2S 12晶体竖线Δ V（Li）竖线（max）= 0.13）。0.03）。这表明Li离子沿着传导路径移动的势垒E-a在从（Li 2S）（5）（GeS 2）（P2 S 5）玻璃到Li 10 GeP 2S 12晶体的转变上降低。在这里，我们提出，降低的垂直酒吧Δ V（Li）垂直酒吧（最大）的原因是在玻璃-晶体转变过程中的σ（300 K）和E-a的大规模改善的结构起源。(C)2017 Elsevier B. V.版权所有。
We carried out synchrotron X-ray diffraction and time-of-flight neutron diffraction experiments for a lithium-ion conductor, (Li2S)(5)(GeS2)(P2S5) glass, prepared by mechanical alloying. The three-dimensional structure and the conduction pathways of Li ions in (Li2S)(5)(GeS2)(P2S5) glass were visualized by combining reverse Monte Carlo (RMC) modeling and the bond valence sum (BVS) approach. The electrochemical properties were characterized; the material demonstrated an electrical conductivity, sigma(300) (K), of 1.5 x 10(-5)S/cm at 300 I( and an activation energy, E-a, of 55 kJ/mol. In addition, it was found that the most advanced lithium-ion conductor, Li10GeP2S12 crystal (sigma(300K) = 1.2 x 10(-2) S/cm and E-a = 24 kJ/mot), could be obtained by aging the (Li2S)(5)(GeS2)(P2S5) glass at 803 K. By comparing the conduction pathways of Li ions in (Li2S)(5)(GeS2)(P2S5) glass with those in Li10GeP2S12 crystal, we found that vertical bar Delta V(Li)vertical bar(max), the maximum BV mismatch value for Li ions, for (Li2S)(5)(GeS2)(P2S5) glass (vertical bar Delta V(Li)vertical bar(max) = 0.13) was significantly larger than that for Li10GeP2S12 crystal vertical bar Delta V(Li)vertical bar(max) = 0.03). This indicates that the potential barrier, E-a, for Li ions moving along the conduction pathways lowers on the transition from (Li2S)(5)(GeS2)(P2S5) glass to Li10GeP2S12 crystal. Here, we propose that the lowering of the vertical bar Delta V(Li)vertical bar(max) is the reason for the structural origin of the massive improvement in sigma(300K) and E-a during the glass-to-crystal transition. (C) 2017 Elsevier B.V. All rights reserved.