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A Stable Cathode-Solid Electrolyte Composite for Long-Cycle-Life, High Voltage Solid-State Sodium-ion Batteries

submitted on 29.07.2020, 00:02 and posted on 29.07.2020, 10:47 by Erik Wu, Swastika Banerjee, HANMEI TANG, Peter M. Richardson, Jean-Marie Doux, Ji Qi, Zhuoying Zhu, Antonin Grenier, Yixuan Li, Enyue Zhao, Grayson Deysher, Han Nguyen, Ryan Stephens, Guy Verbist, Karena W. Chapman, Raphaële J. Clément, Abhik Banerjee, Ying Shirley Meng, Shyue Ping Ong

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 Na3-xY1-xZrxCl6 (NYZC) as an ion conductor that is both electrochemically stable (up to 3.8 V vs. Na/Na+) and chemically compatible with oxide cathodes. Its high ionic conductivity of 6.6 x 10-5 S cm-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°C. These findings highlight the immense potential of halide ion conductors for SSSB applications.


Email Address of Submitting Author


University of California, San Diego


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

R. S. and G. V. are employees of Shell International Exploration and Production Inc., USA and Shell Global Solutions International BV, Netherlands, respectively. A patent was filed for this work through the UCSD Office of Innovation and Commercialization.

Version Notes

This version of the manuscript was submitted to Nature Energy on July 21, 2020.