A stable cathode-solid electrolyte composite for high-voltage, long- cycle-life solid-state sodium-ion batteries

EA Wu and S Banerjee and HM Tang and PM Richardson and JM Doux and J Qi and ZY Zhu and A Grenier and YX Li and EY Zhao and G Deysher and E Sebti and H Nguyen and R Stephens and G Verbist and KW Chapman and RJ Clement and A Banerjee and YS Meng and SP Ong, NATURE COMMUNICATIONS, 12, 1256 (2021).

DOI: 10.1038/s41467-021-21488-7

Rechargeable solid-state sodium-ion batteries (SSSBs) hold great promise for safer and more energy-dense energy storage. However, the poor electrochemical stability between current sulfide-based solid electrolytes and high-voltage oxide cathodes has limited their long-term cycling performance and practicality. Here, we report the discovery of the ion conductor Na3-xY1-xZrxCl6 (NYZC) that is both electrochemically stable (up to 3.8V vs. Na/Na+) and chemically compatible with oxide cathodes. Its high ionic conductivity of 6.6 x 10(-5)Scm(-1) at ambient temperature, several orders of magnitude higher than oxide coatings, is attributed to abundant Na vacancies and cooperative MCl6 rotation, resulting in an extremely low interfacial impedance. A SSSB comprising a NaCrO2+NYZC composite cathode, Na3PS4 electrolyte, and Na-Sn anode exhibits an exceptional first-cycle Coulombic efficiency of 97.1% at room temperature and can cycle over 1000 cycles with 89.3% capacity retention at 40 degrees C. These findings highlight the immense potential of halides for SSSB applications. Rechargeable solid-state sodium-ion batteries hold great promise for safer and more energy-dense energy storage. Here, the authors show a new sodium-based halide, Na3-xY1-xZrxCl6, for sodium-all-solid-state batteries with enhanced ionic conductivity and long-term cycling stability.

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