Zachary Hood1 2 Xiaoming Liu2 Younan Xia1 Miaofang Chi2

1, Georgia Institute of Technology, Atlanta, Georgia, United States
2, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States

Sulfide-based sodium solid electrolytes are expected to improve next-generation energy storage technology on the basis of energy density, safety, cost, etc. Yet inherent limitations, especially the water and air stability, represent grand challenges for these materials to be processed into thin films for real batteries in electric vehicles and portable electronics [1-4]. Therefore, the exploration of new Na-ion superionics is of special importance to develop new robust Na-batteries and has attracted intense attention in recent years. Here, we show that Na4P2S6 and Na3SbS4 hold excellent air and water tolerance and desirable ionic conductivities as solid electrolytes [5-6]. Soft-chemistry approaches were used to produce these new solid electrolytes, and their electrolyte properties were investigated using various electrochemical methods. Their lattice structures and ion mobility were studied by combining first-principles analysis with advanced electron microscopy imaging, and these properties were further linked to their macroscopic performance. We also show that both materials hold promising electrochemical properties for batteries that employ sodium metal anodes. Our results provide valuable insights into the design of superionic materials with high stability and tolerance for next-generation solid-state batteries. Their potential applications in other electrochemical devices will also be discussed.

Research sponsored by the Materials Sciences and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy. Microscopy performed as part of a user project at Oak Ridge National Laboratory’s Center for Nanophase Materials Sciences (CNMS), which is a U.S. DOE User Facility.

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4. H. Wang, Y. Chen, Z.D. Hood, G. Sahu, A.S. Pandian, J.K. Keum, K. An, C. Liang. Angewandte Chemie International Edition 55, 30 (2016): 8551-8555.
5. Hood et. al., In preparation.
6. Hood et. al., In preparation.