The effect of adding CeO2 on the lithium-ion conductivity of PEO solid electrolytes in all solid-state batteries

Polyethylene oxide (PEO) is used as a solid electrolyte in lithium solid-state batteries. Recently, research has been actively conducted to control lithium-ion conductivity by adding ceramic fillers. In this study, unlike previous research, ultra-nano-sized ceria (CeO2) was used as a ceramic filler, added in the range of 0 to 20 wt%. The sample resistance was analyzed using the 2-probe AC impedance method. The highest ionic conductivity was observed when 7.5 wt% of CeO2 was added to the PEO, attributed to the increased amorphous region within the PEO. A Li|solid electrolyte|Li symmetric cell was fabricated using the 7.5 wt% added solid electrolyte. It exhibited low cell overpotential at room temperature and demonstrated stable cycling characteristics for over 300 hours.