Oxygen Vacancy-Li2ZrO3: A New Choice for Boosting Homogenous Distribution and Transport of Lithium Ion in Composite Solid-State Electrolytes

YR Wang and TM Fang and C Wang and SY Wang and K Yang and J Biao and DH Li and DJ Yang and YB He and YZ Xia, ADVANCED MATERIALS, 37 (2025).

DOI: 10.1002/adma.202505209

The low concentration and inhomogenous distribution of free lithium ion (Li+) in composite polymer electrolytes (CPEs) greatly restrict the Li+ transport, cycle stability and rate performance of all solid-state batteries. In this work, lithium zirconate with superficial oxygen (O)-vacancies (O-LZO) is reported as a new Li+ conductors for polyethylene oxide (PEO)-based CPEs (PEO@O-LZO). The O-LZO demonstrates exceptional Li+ transport capability, and its superficial O-vacancies efficiently adsorb anions to facilitate the dissociation of lithium salts, leading a high concentration of free Li+ in CPEs. Furthermore, the electropositive equilibrium charge layer of O-vacancies avoids the aggregation of Li+ near the filler and achieves a stable interface to promote the efficient and continuous Li+ transport. These effects contribute to a high Li+ conductivity of 1.63 x 10-4 S cm-1 and a Li+ migration number of 0.35 for PEO@O-LZO at 40 degrees C. The assembled battery (LiFePO4/PEO@O-LZO/Li) exhibits a capacity of 120 mAh g-1 at 3 C and stable cycling performance with an 80.5% capacity retention after 800 cycles at 1 C and 40 degrees C, maintaining excellent coulombic efficiency. This work provides a design principle of fillers to regulate Li+ concentration and distribution in CPEs for efficient solid-state lithium metal batteries.

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