POLYPROPYLENE SEPARATOR GRAFTED WITH HYDROPHILIC MONOMERS FOR LITHIUMBATTERIES

Separator materials play an important part in lithium nonaqueous recha rgeable battery operation. Their wettability limits the performances o f batteries. To avoid wetting agents or undesirable substances to the electrode system, grafted separators are used. Acrylic acid (AA) and d iethyleneglycol-dimethacrylate (DEGDM) are grafted onto 50 mu m polypr opylene films. The physicochemical properties of the polymer films obt ained are studied versus the characteristics of grafting. The influenc e of temperature and monomer content on grafting kinetics is pointed o ut. Cycling performances of secondary lithium batteries including thes e grafted films as separators are also presented.