COATED SEPARATOR FOR ENERGY STORAGE DEVICE

An energy storage device includes an anode; a cathode; an electrolyte in contact with both the anode and the cathode; and an electrically non-conductive, porous separator between the anode and the cathode. At least one major surface of the porous separator includes a coating with a layer having a star polymer. The star polymer includes a hydrophobic core and at least three arms, wherein at least some of the arms includes ion-conductive polar functional groups.