Szczuka Conrad, Karasulu Bora, Groh Matthias F, Sayed Farheen N, Sherman Timothy J, Bocarsly Joshua D, Vema Sundeep, Menkin Svetlana, Emge Steffen P, Morris Andrew J, Grey Clare P
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
J Am Chem Soc. 2022 Sep 14;144(36):16350-16365. doi: 10.1021/jacs.2c01913. Epub 2022 Aug 30.
All-solid-state batteries based on non-combustible solid electrolytes are promising candidates for safe energy storage systems. In addition, they offer the opportunity to utilize metallic lithium as an anode. However, it has proven to be a challenge to design an electrolyte that combines high ionic conductivity and processability with thermodynamic stability toward lithium. Herein, we report a new highly conducting solid solution that offers a route to overcome these challenges. The Li-P-S ternary was first explored via a combination of high-throughput crystal structure predictions and solid-state synthesis (via ball milling) of the most promising compositions, specifically, phases within the LiP-LiS tie line. We systematically characterized the structural properties and Li-ion mobility of the resulting materials by X-ray and neutron diffraction, solid-state nuclear magnetic resonance spectroscopy (relaxometry), and electrochemical impedance spectroscopy. A LiP-LiS metastable solid solution was identified, with the phases adopting the fluorite (LiS) structure with P substituting for S and the extra Li ions occupying the octahedral voids and contributing to the ionic transport. The analysis of the experimental data is supported by extensive quantum-chemical calculations of both structural stability, diffusivity, and activation barriers for Li transport. The new solid electrolytes show Li-ion conductivities in the range of established materials, while their composition guarantees thermodynamic stability toward lithium metal anodes.
基于不可燃固体电解质的全固态电池是安全储能系统的有前途的候选者。此外，它们提供了使用金属锂作为阳极的机会。然而，事实证明，设计一种兼具高离子导电性、可加工性以及对锂具有热力学稳定性的电解质是一项挑战。在此，我们报告一种新型高导电固溶体，它为克服这些挑战提供了一条途径。通过高通量晶体结构预测与最具前景的组成（具体而言，LiP-LiS连线上的相）的固态合成（通过球磨）相结合，首次对Li-P-S三元体系进行了探索。我们通过X射线和中子衍射、固态核磁共振光谱（弛豫测量）以及电化学阻抗谱，系统地表征了所得材料的结构性质和锂离子迁移率。确定了一种LiP-LiS亚稳固溶体，其中各相采用萤石（LiS）结构，P取代S，额外的锂离子占据八面体空隙并有助于离子传输。对实验数据的分析得到了关于结构稳定性、扩散率以及锂传输活化能垒的大量量子化学计算的支持。新型固体电解质的锂离子电导率处于现有材料的范围内，同时其组成保证了对锂金属阳极的热力学稳定性。
