A long life solid-state lithium–oxygen battery enabled by a durable oxygen deficient flower-like CeO2 microsphere based solid electrolyte

Abstract

Rechargeable lithium–oxygen batteries (Li–O₂) are one of the most promising candidates for energy storage and electric vehicles due to their high energy density. Nevertheless, their realistic applications are frequently restricted by the safety problems and serious side reactions caused by the use of nonaqueous liquid electrolytes, which makes the service life and safety of these batteries unable to meet the requirements. Here, a durable composite electrolyte membrane was prepared by rationally utilizing oxygen vacancies in flower-like CeO₂ microspheres to promote the decomposition of lithium salts and scavenge excess oxygen radicals. The prepared composite electrolyte consists of polyvinylidene fluoride–hexafluoropropylene (PVDF–HFP), LiTFSI salt, Li₇La₃Zr₂O₁₂, and flower-like CeO₂ microspheres. The composite electrolyte exhibits a wide electrochemical window (5.1 V vs. Li/Li⁺), high ionic conductivity (4.86 × 10⁻⁴ S cm⁻¹) and ionic transference number (0.65) at room temperature. The assembled solid-state lithium–oxygen battery with this composite electrolyte can be cycled stably for more than 400 times (about 2000 hours). Moreover, solid-state Li|LiFePO₄ batteries assembled using this composite electrolyte exhibited good cycling stability and high coulombic efficiency as well. This work designs an extraordinary composite electrolyte with both safety and longevity for lithium–oxygen and lithium-ion rechargeable batteries.