Boosting Solid-State Diffusivity and Conductivity in Lithium Superionic Argyrodites by Halide Substitution
Boosting Solid-State Diffusivity and Conductivity in Lithium Superionic Argyrodites by Halide Substitution
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DOI：
10.1002/anie.201814222
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发表时间：
2019-06-24
影响因子：
16.6
通讯作者：
Nazar, Linda F.
中科院分区：
文献类型：
--
作者：
Adeli, Parvin;Bazak, J. David;Nazar, Linda F.
开发高性能的全固态电池取决于找到具有高离子导电性和延展性的固体电解质材料。在这里，我们报告了新的富卤化物的固溶体相在argyrodite Li 6PS 5Cl家庭，Li 6-xPS 5-xCl 1 +x，并结合联合收割机电化学阻抗谱，中子衍射，和Li-7 NMR MAS和PFG光谱显示，增加Cl-/S2-的比例有一个系统的，和显着的影响，锂离子在晶格中的扩散。在固溶体制度的极限处的相Li5.5PS4.5Cl1.5在298 K下表现出9.4 +/- 0.1mScm（-1）的冷压电导率（在烧结时为12.0 +/- 0.2mScm（-1））-几乎是在相同处理条件下的Li 6PS 5Cl的四倍，并且与亚稳态超离子Li 7 P3 S11相当。由二价S2-取代一价Cl-引起的移动的Li-离子和周围框架阴离子之间的相互作用减弱在增强Li+-离子扩散性方面起主要作用，沿着增加的位点无序和更高的锂空位群体。
Developing high-performance all-solid-state batteries is contingent on finding solid electrolyte materials with high ionic conductivity and ductility. Here we report new halide-rich solid solution phases in the argyrodite Li6PS5Cl family, Li6-xPS5-xCl1+x, and combine electrochemical impedance spectroscopy, neutron diffraction, and Li-7 NMR MAS and PFG spectroscopy to show that increasing the Cl-/S2- ratio has a systematic, and remarkable impact on Li-ion diffusivity in the lattice. The phase at the limit of the solid solution regime, Li5.5PS4.5Cl1.5, exhibits a cold-pressed conductivity of 9.4 +/- 0.1mScm(-1) at 298K (and 12.0 +/- 0.2mScm(-1) on sintering)-almost four-fold greater than Li6PS5Cl under identical processing conditions and comparable to metastable superionic Li7P3S11. Weakened interactions between the mobile Li-ions and surrounding framework anions incurred by substitution of divalent S2- for monovalent Cl- play a major role in enhancing Li+-ion diffusivity, along with increased site disorder and a higher lithium vacancy population.