Interfacial Coordination Engineering to Boost Li-Ion Conduction in Economic Zr-Based Halide Electrolytes.

Wu, Mengyi; Su, Han; Zhong, Yu; Zhao, Fanya; Tu, Jiangping; Wang, Xiuli · Adv Mater · 2025

basic_science · Level V

Where this comes from

Abstract

Halide solid electrolytes (HSEs) have seen rapid progress in the development of all-solid-state lithium batteries (ASSLBs), offering favorable lithium-ion transport properties, broad electrochemical stability, and strong interfacial compatibility with high-voltage oxide cathodes. However, developing HSEs that simultaneously offer high ionic conductivity and low cost remains a significant challenge. Most high-conductivity halides rely on expensive metal elements, whereas cost-effective Zr-based halides are limited by their relatively low ionic conductivity. In this study, a new composite electrolyte (LA/LZCO) is developed via an interfacial coordination reaction between Zr-based oxychlorides (LZCO) and Li<sub>1.3</sub>Al<sub>0.3</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> (LATP). The coordination between PO<sub>4</sub> <sup>3-</sup> groups in LATP and Zr<sup>4+</sup> in LZCO induces local structural disorder, promoting LZCO amorphization. As a result, the ionic conductivity of LA/LZCO composite electrolyte is enhanced by more than twofold compared to LZCO, reaching 2.81 mS cm<sup>-1</sup>, among one of the highest reported for Zr-based halide electrolytes. When integrated into ASSLBs with NCM83125 cathodes, the composite electrolyte enables excellent cycling stability, with 92.4% and 87.5% capacity retention after 1000 cycles at 0.5 and 2 C under 4.25 V. Even at an elevated cut-off voltage of 4.5 V, 85.1% capacity is retained after 380 cycles, highlighting the promise of this composite strategy for high-energy, long-life ASSLBs.