A Li2CuPS4 superionic conductor: a new sulfide-based solid-state electrolyte
A Li2CuPS4 superionic conductor: a new sulfide-based solid-state electrolyte
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Li2CuPS4超离子导体：新型硫化物固态电解质
DOI：
10.1039/c9ta01317b
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发表时间：
2019-05-28
影响因子：
11.9
通讯作者：
Zhu, Hong
中科院分区：
文献类型：
--
作者：
Xu, Zhenming;Chen, Ronghan;Zhu, Hong
基于密度泛函理论（DFT）计算，提出了一种新的硫化物基超离子导体--气晶石结构的Li 2CuPS 4（LCPS）材料.我们的理论研究表明，LCPS材料是热力学和动力学稳定的，很可能是实验合成。LCPS可以在高锂化学势下形成电子绝缘但离子导电的中间相，通过钝化其表面并由于有限的动力学而增强其电化学稳定性来防止进一步还原或氧化。LCPS是一种超离子导体，在300 K下表现出比现有技术Li 10 GeP 2S 12材料高得多的84.9 mS cm（-1）的离子电导率，这是由于Li离子结合较弱以及由于Cu+阳离子的可变价态而形成Li空位的能量补偿。LCPS超离子导体有望用作全固态锂离子电池的固态电解质材料。此外，通过减小阴离子元素和非锂阳离子元素之间的电负性差异，首次确定了制备具有Li四面体占据的新的超离子导体的替代设计原理。
A new sulfide-based superionic conductor, a kesterite-structured Li2CuPS4 (LCPS) material, was proposed based on density functional theory (DFT) calculations. Our theoretical studies reveal that the LCPS material is thermodynamically and dynamically stable, and very likely to be experimentally synthesized. LCPS can form electronically insulating but ionically conducting interphases at high lithium chemical potential, preventing further reduction or oxidation by passivating its surface and enhancing its electrochemical stability due to the limited kinetics. LCPS is a superionic conductor, exhibiting a much higher ionic conductivity of 84.9 mS cm(-1) at 300 K than the state-of-the-art Li10GeP2S12 material, due to the weaker Li ion binding and the energy compensation for forming Li vacancies due to the variable valence state of the Cu+ cation. The LCPS superionic conductor is promising for use as a solid-state electrolyte material for all-solid-state lithium ion batteries. Moreover, an alternative design principle for fabricating new superionic conductors with Li tetrahedral occupation by reducing the electronegativity difference between the anion element and non-lithium cation elements was identified for the first time.