Strangmüller Stefan, Eickhoff Henrik, Müller David, Klein Wilhelm, Raudaschl-Sieber Gabriele, Kirchhain Holger, Sedlmeier Christian, Baran Volodymyr, Senyshyn Anatoliy, Deringer Volker L, van Wüllen Leo, Gasteiger Hubert A, Fässler Thomas F
Department of Chemistry , Technische Universität München , Lichtenbergstrasse 4 , D-85747 Garching , Germany.
Department of Physics , University of Augsburg , Universitätsstrasse 1 , D-86159 Augsburg , Germany.
J Am Chem Soc. 2019 Sep 11;141(36):14200-14209. doi: 10.1021/jacs.9b05301. Epub 2019 Aug 27.
Solid electrolytes with superionic conductivity are required as a main component for all-solid-state batteries. Here we present a novel solid electrolyte with three-dimensional conducting pathways based on "lithium-rich" phosphidosilicates with ionic conductivity of σ > 10 S cm at room temperature and activation energy of 30-32 kJ mol expanding the recently introduced family of lithium phosphidotetrelates. Aiming toward higher lithium ion conductivities, systematic investigations of lithium phosphidosilicates gave access to the so far lithium-richest compound within this class of materials. The crystalline material (space group 3), which shows reversible thermal phase transitions, can be readily obtained by ball mill synthesis from the elements followed by moderate thermal treatment of the mixture. Lithium diffusion pathways via both tetrahedral and octahedral voids are analyzed by temperature-dependent powder neutron diffraction measurements in combination with maximum entropy method and DFT calculations. Moreover, the lithium ion mobility structurally indicated by a disordered Li/Si occupancy in the tetrahedral voids plus partially filled octahedral voids is studied by temperature-dependent impedance and Li NMR spectroscopy.
具有超离子导电性的固体电解质是全固态电池的主要组成部分。在此，我们展示了一种基于“富锂”磷硅化物的新型固体电解质，其具有三维导电通道，在室温下离子电导率σ>10 S cm ，活化能为30 - 32 kJ mol ，扩展了最近引入的磷代四价元素锂化物家族。为了实现更高的锂离子电导率，对磷硅化锂进行了系统研究，从而获得了这类材料中迄今为止锂含量最高的化合物。这种晶体材料（空间群3）表现出可逆的热相变，通过球磨法由元素合成，随后对混合物进行适度热处理即可轻松获得。通过结合最大熵法和密度泛函理论（DFT）计算的变温粉末中子衍射测量，分析了通过四面体和八面体空隙的锂扩散途径。此外，通过变温阻抗和锂核磁共振光谱研究了由四面体空隙中无序的Li/Si占据以及部分填充的八面体空隙在结构上所表明的锂离子迁移率。
