Composite Separator and Lithium Ion Battery Comprising Said Separator and Method for Producing Said Composite Separator

A composite separator is provided which includes a polymer membrane, a binder, a solid inorganic lithium-ion conductor and a liquid electrolyte. The solid inorganic lithium-ion conductor is present in the composite separator in a higher volume and weight proportion than the liquid electrolyte. A method for forming the composite separator is also provided, and a lithium-ion battery is provided which includes a composite separator having a polymer membrane, a binder, a solid inorganic lithium-ion conductor and a liquid electrolyte.