High-entropy strategy based on low-cost metal substitution at Zr site for high-performance garnet-type solid-state electrolytes

Garnet-type solid-state electrolytes are celebrated for their exceptional stability against lithium metal, a property that is crucial for developing high safety all solid-state batteries. However, the practical adoption of this electrolyte is hindered by low ionic conductivity and poor interface contact. In this paper, we propose a novel strategy for fabricating the garnet-type high-entropy oxide solid-state electrolyte Li 6 La 3 Zr 0.5 Ti 0.5 Cr 0.5 Sn 0.5 O 12 (LLZTCSO) by low-cost partial substitution of Zr with Ti, Cr, Sn in the LLZO. By the lattice distortion effect generated by Zr substitution, LLZTCSO achieves rapid lithium ion migration, high air stability, and excellent mechanical properties. As a result, Li/Ag@LLZTCSO/Li symmetric cell shows lower interfacial impedance (100.5 Ω cm 2 ) and higher critical current density (1.428 mA cm −2 ) than LLZO. The LiFePO 4 (LFP)/Ag@LLZTCSO/Li full cell also exhibits good rate capability (145.06 mA h g −1 at 0.5C) and cycling performance (capacity degradation of 12.13% after 100 cycles at 0.1C). This study outlines a novel approach for the synthesis of high-performance garnet-type electrolytes for all-solid-state lithium metal batteries, providing important references for the design of garnet-type solid-state electrolytes in the future.