Effects of Halogen and Sulfur Mixing on Lithium-Ion Conductivity in Li7-x-y(PS4)(S2-x-yClxBry) Argyrodite and the Mechanism for Enhanced Lithium Conduction
Effects of Halogen and Sulfur Mixing on Lithium-Ion Conductivity in Li7-x-y(PS4)(S2-x-yClxBry) Argyrodite and the Mechanism for Enhanced Lithium Conduction
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DOI：
10.1021/acs.jpcc.2c03780
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发表时间：
2022-08-12
影响因子：
3.7
通讯作者：
Kuwata, Naoaki
中科院分区：
文献类型：
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作者：
Masuda, Naoya;Kobayashi, Kiyoshi;Kuwata, Naoaki
含有硫化磷的全固态锂离子电池是很有前途的下一代电池，因为它们比液体电解质电池具有更高的能量密度。富卤素银柱石li7 - α (PS4)(s2 - α X α)(α > 1) （X = Cl, Br， I; α > 1）比其他硫化磷具有更高的离子电导率；改变单个阴离子的含量使卤素取代成为可能。然而，目前还没有合适的模型来描述这些银柱石中的离子传导路径。在这里，我们讨论了一系列的成分图来解释Li7-x-y(PS4)(S2-x-yClxBry) （x + y > 1）的锂离子电导率。Li-5.4(PS4)（S0.4Cl1.0Br0.6）和Li-5.4(PS4) -(S0.4Cl0.6Br1.0)的离子电导率最高，为11.6 mS/cm。对Li7-x-y(PS4)(S2-x-yClxBry) （x + y > 1）采用键价和映射和最大熵方法。结果表明，这些银柱石具有围绕卤化物或硫化物离子的锂笼状结构，并通过间隙位（16e）在笼状结构之间形成锂离子传导路径。氯离子、溴离子和硫离子在4a和4d位点上的无序程度控制笼间传导路径的长度；笼间的短锂离子传导路径增强了锂离子的导电性。这些结果可以启发开发具有增强离子电导率的富卤素成分li7 - α (PS4)(s2 - α X α)（α > 1）。
All-solid-state lithium-ion batteries containing phosphorus sulfides are promising next-generation batteries because they have higher energy densities than their liquid-electrolyte counterparts. Halogen-rich argyrodites, Li7-alpha(PS4)(S2-alpha X alpha) (alpha > 1) (X = Cl, Br, I; alpha > 1), exhibit higher ionic conductivities than other phosphorus sulfides; varying the content of a single anion enables halogen substitution. However, there is no appropriate model for the ion-conducting path in these argyrodites. Herein, we discuss a range of composition maps to explain the lithium-ion conductivity of Li7-x-y(PS4)(S2-x-yClxBry) (x + y > 1). The ionic conductivities (similar to 11.6 mS/cm) of Li-5.4(PS4)(S0.4Cl1.0Br0.6) and Li-5.4 (PS4)-(S0.4Cl0.6Br1.0) are among the highest reported. Bond valence sum mapping and maximum entropy methods for Li7-x-y(PS4)(S2-x-yClxBry) (x + y > 1) were used. The results showed that these argyrodites have a lithium-cage structure surrounding the halide or sulfide ions at the 4d sites and a lithium-ion-conduction path between the cages via an interstitial site (16e). The degree of disorder of chloride, bromide, and sulfide ions on the 4a and 4d sites controls the conduction path length between the cages; a short lithium-ion-conduction path between the cages enhances lithium-ion conductivity. These results could inspire the development of halogen-rich compositions of Li7-alpha(PS4)(S2-alpha X alpha) (alpha > 1) with enhanced ionic conductivities.