To obtain a composition having a very high cation transport ratio, a small polarization and a high conductivity by covalently bonding a polymeric compound to an alkali siloxyaluminate.
The alkali siloxyaluminate has a structure represented by the formula (wherein M+ is e.g. a lithium or sodium ion which corresponds to an electrolyte of a l ithium ion battery or a sodium ion battery). An example of the method for obtaining the alkali siloxyaluminate consists of reacting a dialkylsilanediol with lithium aluminum hydride. The alkali siloxyaluminate can be covalently bonded to a polymeric compound through a reaction of the hydroxyl groups of the respective substituents with epoxy groups. When the polymeric compound is a butadiene skeleton polymer or the like, it can be used as a battery separator as such and can therefore permit reduction in the weight of a battery.
IIZUKA HIROSHI
KISHIDA MASATOSHI