Bulk-type all-solid-state Na-ion batteries (ASNBs) employing inorganic Na-ion conductors and operating at room temperature are considered as promising candidates for large-scale energy storage systems. However, their realization has been impeded by low ionic conductivity, instability in air of the solid electrolytes, and poor ionic contacts among the constituents of the electrodes. Here, we report novel glass-ceramic xNaI·(1 - x)Na3SbS4 superionic conductors (maximum Na+ conductivity of 0.74 mS cm-1 at 30 °C, for x = 0.10) obtained from scalable methanol solutions. Comprehensive spectroscopic evidence, density functional theory calculations, and electrochemical analysis suggest the decisive role of I- incorporated in the disordered domains at the nanoscale in the overall Na+ transport. Furthermore, the solution-derived NaI·Na3SbS4 forms uniform coating layers on the surface of the active material FeS2, providing unobstructed ionic transport pathways in the electrodes. The good electrochemical performance of FeS2/Na-Sn ASNBs at 30 °C is demonstrated.
Bibliographical noteFunding Information:
Y. S. J. research was supported by the Technology Development Program to Solve Climate Changes and by Basic Science Research Program of the National Research Foundation (NRF) funded by the Ministry of Science & ICT (grant no. NRF-2017M1A2A2044501 and 2018R1A2B6004996), by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (No. CAP-18-AB-1300), and by the Materials and Components Technology Development Program of MOTIE/KEIT (grant No. 10076731). J. H. L. acknowledges the support from Creative Materials Discovery Program through the NRF (2017M3D1A1040828).
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)