Water-mediated synthesis of cost-effective Fe3+ substituted LaCl3-based halide solid-state electrolyte

Solid-state electrolytes (SSEs) are pivotal in the development of high-performance all-solid-state lithium batteries (ASSLBs). Traditionally, halides have been synthesized primarily using solid-state techniques, with wet chemistry synthesis being less frequently utilized. In this work, the cost-effective Fe3+ substituted LaCl3-based halide solid-state electrolyte was synthesized via a water-mediated method for the first time. The optimized Li0.5Fe0.25La0.58Cl3 exhibits an ionic conductivity of 0.741 mS cm-1 at room temperature (RT), accompanied by a low activation energy of 0.26 eV. Additionally, the SSE displays a uniform crystal structure and excellent grain fusion, which is crucial for maintaining intimate solid-solid interfacial contacts within the battery. The ASSLBs based on LiCoO2 demonstrate good cycling stability. This research contributes novel insights to the expansion of the LaCl3-based electrolyte family and diversifies the available synthetic methodologies.