Elucidating lithium-ion and proton dynamics in anti-perovskite solid electrolytes
Elucidating lithium-ion and proton dynamics in anti-perovskite solid electrolytes
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DOI：
10.1039/c8ee00779a
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发表时间：
2018-10-01
影响因子：
32.5
通讯作者：
Islam, M. Saiful
中科院分区：
文献类型：
--
作者：
Dawson, James A.;Attari, Tavleen S.;Islam, M. Saiful
全固态锂离子电池目前引起了相当大的研究关注，因为与传统的液体电解液设备相比，它们为提高能量密度和安全性提供了一个可行的机会。富锂反钙钛矿Li3-xOHxCl作为一种潜在的固体电解质材料最近引起了人们的兴趣，但它的锂和质子传输能力与组成的关系还没有得到充分的表征。在这项工作中，我们应用从头算分子动力学和H-1，H-2和Li-7固体核磁共振谱相结合的方法研究了Li_3-xOHxCl中锂离子和质子的迁移率。我们的计算预测了Li3OCl的一个强烈的放热水化热，这解释了这种材料很容易吸湿，而合成无水样品的难度很大。结果表明，锂离子的电导活化能随质子含量的增加而增大。原子模拟表明锂离子快速扩散，但排除了长程质子扩散的贡献。这些发现得到了变温固体核磁共振实验的支持，这些实验表明质子的局域运动和锂离子的长程迁移率密切相关。我们的研究结果证实了Li3-xOHxCl是一种很有前途的全固态锂离子电池固体电解质材料。
All-solid-state Li-ion batteries are currently attracting considerable research attention as they present a viable opportunity for increased energy density and safety when compared to conventional liquid electrolyte-based devices. The Li-rich anti-perovskite Li3-xOHxCl has generated recent interest as a potential solid electrolyte material, but its lithium and proton transport capabilities as a function of composition are not fully characterised. In this work, we apply a combination of ab initio molecular dynamics and H-1, H-2 and Li-7 solid-state NMR spectroscopy to study the mobility of lithium ions and protons in Li3-xOHxCl. Our calculations predict a strongly exothermic hydration enthalpy for Li3OCl, which explains the ease with which this material absorbs moisture and the difficulty in synthesising moisture-free samples. We show that the activation energy for Li-ion conduction increases with increasing proton content. The atomistic simulations indicate fast Li-ion diffusion but rule out the contribution of long-range proton diffusion. These findings are supported by variable-temperature solid-state NMR experiments, which indicate localised proton motion and long-range Li-ion mobility that are intimately connected. Our findings confirm that Li3-xOHxCl is a promising solid electrolyte material for all-solid-state Li-ion batteries.