β-Cyclodextrin-modified porous ceramic membrane with enhanced ionic conductivity and thermal stability for lithium-ion batteries

Exploration of advanced separator with high ambient temperature ionic conductivity, excellent electrochemical stability, high thermal stability, and superior flame-retarding ability is crucial to realize the large-scale application of high energy density lithium-ion batteries (LIBs). Hence, a rationally designed porous ceramic membrane (PCM) composed of nanosized Al2O3 as inorganic filler, poly(vinylidene fluoride) (PVDF) as binder, and β-cyclodextrin (β-CD) as modifier exhibits the significantly enhanced physical and electrochemical properties in porosity, electrolyte wettability, ionic conductivity, thermal stability, and flame-retarding ability compared to commercial polypropylene (PP) separators. Particularly, the LiNi0.8Co0.1Mn0.1O2/Li half cells and LiNi0.8Co0.1Mn0.1O2/graphite pouch cells assembled with 3 wt.% β-CD-modified PCM (PCM-CD3) as separators both present the superior electrochemical performance in terms of specific capacity, capacity retention, rate capability, and high temperature cycling stability. This β-CD-modified PCM is highly expected to pave the road for the practical implementation of high safety power LIBs.