Local structural features of medium-entropy garnet with ultra-long cycle life

High-entropy ceramics (HECs) have gained great attention as one of the rapidly growing families of high-entropy materials. Increasing the species yields enhanced properties owing to high configurational entropy and elemental synergies, alluding to the potential of HECs in designing materials with tailored properties. However, the question is obscure as to whether the multiple elements show priority in the arrangement in the structure, as well as how they regulate the bond length. Here, we synthesize a medium-entropy garnet-structured electrolyte Li6La3Zr0.5Hf0.5Ta0.5Nb0.5O12 (ME-LLZO) and elucidate its short-range structure based on the calculated supercell and neutron pair distribution function (PDF) refinement. Extended bottleneck size, elongated Li–O bond length, and local clustering of 16a sites, where tetravalent ions prefer to be the first-nearest octahedrons of pentavalent ions, are observed. Differences between the multiple cations inevitably influence the short-range structure, and our study provides a new paradigm for future exploration of HEC-based solid-state electrolytes.