Large-Scale Simulation Unveiled Superior Potassium-Based Solid Electrolyte with High Ionic Conductivity and Excellent Electrochemical Stability in M_{5}YSi_{4}O_{12} (M=Li,K)

Simultaneously achieving interfacial stability and high room-temperature ionic conductivity (≥10^{−3} S/cm) in solid-state electrolytes is one of the most significant challenges in the development of all-solid-state batteries. In this study, by combining first-principles simulations and large-scale...

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Main Authors: Zhao Li, Jiaxiang Li, Congwei Xie, Keith Butler, Fei Du, Yu Xie
Format: Article
Language:English
Published: American Physical Society 2025-08-01
Series:PRX Energy
Online Access:http://doi.org/10.1103/8wkh-238p
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Summary:Simultaneously achieving interfacial stability and high room-temperature ionic conductivity (≥10^{−3} S/cm) in solid-state electrolytes is one of the most significant challenges in the development of all-solid-state batteries. In this study, by combining first-principles simulations and large-scale machine-learning molecular dynamics modeling, we demonstrate K_{5}YSi_{4}O_{12} is such an outstanding electrolyte for K-ion batteries that showcases both intrinsic interfacial stability with metal anode and fast ion diffusivity. Conversely, Li_{5}YSi_{4}O_{12} only exhibits mediocre performance for Li-ion batteries. Our results show Li_{5}YSi_{4}O_{12} is thermodynamically unstable and will be reduced by the metal anode, whereas thermodynamically stable K_{5}YSi_{4}O_{12} presents a wide electrochemical stability window of 0.00–3.27 V versus K/K^{+}, suggesting it is stable in contact with potassium metal. The predicted ionic conductivity is 0.43 and 3.63 mS/cm for Li_{5}YSi_{4}O_{12} and K_{5}YSi_{4}O_{12}, respectively. Moreover, a significant size effect has been observed in K_{5}YSi_{4}O_{12}, where the accurate ionic conductivity can only be obtained through large-scale simulations. Further analysis reveals low energy barrier and long hopping distance are responsible for the higher ionic conductivity in K_{5}YSi_{4}O_{12}. This work identifies an excellent electrolyte candidate for K-ion batteries and underscores the importance of scale in the modeling of ionic conductivity.
ISSN:2768-5608