ELECTRODE SEPARATOR

摘要

A method of making an electrode separator for use in an electrochemical device comprises a non-woven fabric whose fibres comprise a polyolefin, having groups bonded to them by a graft polymerisation reaction between the fibre surfaces and a vinyl monomer which is capable of reacting with an acid or a base to form a salt directly or indirectly. The method includes the step of reducing the thickness of the fabric by application to it of heat and pressure under such conditions that (a) the reduction in thickness can be at least partially retained until the fabric is exposed to water or an aqueous solution, and (b) the reduction in thickness is then at least partially recovered when the fabric is exposed to water or an aqueous solution.