A stable cathode-solid electrolyte composite for high-voltage, long-cycle-life solid-state sodium-ion batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33623048.
- Also identified by DOI 10.1038/s41467-021-21488-7 and PMC identifier 7902639.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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 Na<sub>3-x</sub>Y<sub>1-x</sub>Zr<sub>x</sub>Cl<sub>6</sub> (NYZC) that is both electrochemically stable (up to 3.8 V vs. Na/Na<sup>+</sup>) and chemically compatible with oxide cathodes. Its high ionic conductivity of 6.6 × 10<sup>-5</sup> S cm<sup>-1</sup> at ambient temperature, several orders of magnitude higher than oxide coatings, is attributed to abundant Na vacancies and cooperative MCl<sub>6</sub> rotation, resulting in an extremely low interfacial impedance. A SSSB comprising a NaCrO<sub>2</sub> + NYZC composite cathode, Na<sub>3</sub>PS<sub>4</sub> 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 halides for SSSB applications.