Divalent anion-driven framework regulation in Zr-based halide solid electrolytes for all-solid-state batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41310361.
- Also identified by DOI 10.1038/s41467-025-65702-2 and PMC identifier 12660725.
- 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
Research into solid electrolytes for all-solid-state batteries has intensified due to demand for safer and higher-energy-density batteries. Halide solid electrolytes are valued for their high ionic conductivity, oxidative stability, and ductility. Among them, Li<sub>2</sub>ZrCl<sub>6</sub> is cost-effective but has a relatively lower Li⁺ ionic conductivity (0.4 mS cm<sup>-1</sup> at 25 °C) compared to other halides, such as Li<sub>3</sub>InCl<sub>6</sub> (> 1 mS cm<sup>-1</sup> at 25 °C). Here, we elucidate a fundamental mechanism of divalent-anion-driven framework modification that enables enhanced ionic conduction in Zr-based halides. Specifically, we demonstrate enhanced Li<sup>+</sup> conductivities for oxygen- (0.8Li<sub>2</sub>O-ZrCl<sub>4</sub>: 1.78 mS cm<sup>-1</sup> at 25 °C) and sulfur- (0.8Li<sub>2</sub>S-ZrCl<sub>4</sub>: 1.01 mS cm<sup>-1</sup> at 25 °C) substituted lattices. Synchrotron-based X-ray analyses identify distinct anionic sublattices and first-principles calculations reveal that divalent anions locally cluster within the lattice, inducing structural distortion and Li-site destabilization. These changes widen lithium conduction channels and alter the bonding environment, weakening and diversifying Li-Cl interactions. As a result, the energy landscape for lithium migration is flattened, leading to improved ionic conduction. These findings highlight design strategies for divalent-anion-driven framework regulation in halide solid electrolytes.