Can Substitutions Affect the Oxidative Stability of Lithium Argyrodite Solid Electrolytes?
Can Substitutions Affect the Oxidative Stability of Lithium Argyrodite Solid Electrolytes?
复制标题
取代会影响锂银矿固体电解质的氧化稳定性吗？
DOI：
10.1021/acsaem.1c03599
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发表时间：
2022
影响因子：
6.4
通讯作者：
Zeier, Wolfgang G.
中科院分区：
文献类型：
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作者：
Banik, Ananya;Liu, Yunsheng;Ohno, Saneyuki;Rudel, Yannik;Jiménez-Solano, Alberto;Gloskovskii, Andrei;Vargas-Barbosa, Nella M.;Mo, Yifei;Zeier, Wolfgang G.
锂离子导电的银矿由于其高离子电导率而在研究最多的固体电解质中。固态电池的主要问题是固体电解质的稳定性。在这里，我们提出了一个系统的研究的影响，阳离子和阴离子取代的电化学稳定性的Li 6PS 5X使用逐步循环伏安法，光学带隙测量，硬X射线光电子能谱沿着与第一性原理计算。我们观察到，从Li_6PS_5Cl到Li_（6 + x）P_（1-x）M_xS_5I（M = Si ~（4+），Ge ~（4+）），氧化稳定性没有改变。考虑到化学键合表明，价带边缘主要由PS43-单元或未结合的硫化物阴离子的非键合轨道填充，并且这些硫化物基固体电解质中的简单取代不能提高氧化稳定性。这项工作提供了对化学键合对超离子导体稳定性的作用的见解，并表明长期稳定的固态电池需要替代策略。
Lithium-ion conducting argyrodites are among the most studied solid electrolytes due to their high ionic conductivities. A major concern in a solid-state battery is the stability of the solid electrolyte. Here, we present a systematic study on the influence of cationic and anionic substitution on the electrochemical stability of Li6PS5X using stepwise cyclic voltammetry, optical band gap measurements, and hard X-ray photoelectron spectroscopy along with first-principles calculations. We observe that on going from Li6PS5Cl to Li6+xP1–xMxS5I (M = Si4+, Ge4+), the oxidative stability does not change. Considering the chemical bonding shows that the valence band edges are mostly populated by nonbonding orbitals of the PS43–units or unbound sulfide anions and that simple substitutions in these sulfide-based solid electrolytes cannot improve oxidative stabilities. This work provides insights into the role of chemical bonding on the stability of superionic conductors and shows that alternative strategies are needed for long-term stable solid-state batteries.