A sandwich-structured ceramic-gel hybrid electrolyte to realize practical long cycle life Li-air batteries

Abstract

Lithium-air batteries (LABs) have been regarded as the pinnacle of energy storage field owing to their ultrahigh energy density. However, most research focuses on lithium-oxygen batteries that work in pure oxygen instead of ambient air due to Li anode corrosion by the moisture in air atmosphere. Inspired by soft properties of gel polymer electrolyte (GPE) and dense structure characteristics of Li1.5Al0.5Ge1.5(PO4)3 ceramic, a sandwich-structured ceramic/gel hybrid electrolyte is successfully constructed via ultraviolet-irradiation method in this work, in which Li1.5Al0.5Ge1.5(PO4)3 ceramic is helpful in inhibiting Li anode corrosion while GPE is good at optimizing interface compatibility of electrolyte│electrode. The results show that the Li anode in LABs maintains metallic luster even after cycling in ambient air at 10–20% relative humidity (RH) for more than 100 h. Moreover, the interface resistance of Li symmetric cell is sharply reduced (from over 20 kΩ–1 kΩ), and it exhibits an ultralong lifespan (2000 h). Therefore, the lithium-air coin cell with this hybrid electrolyte has achieved more than 4-times the lifetime of that of conventional GPEs. A ‘3.5 cm × 3.5 cm’ pouch cell based on this hybrid electrolyte has also obtained an excellent cycle life of 750 h, further proving its application prospects in LABs.