Separator having a polysulfide barrier layer for lithium-sulfur cells

Abstract

A lithium-sulfur cell includes a lithium-containing anode, a sulfur-containing cathode and a separator arranged between the lithium-containing anode and the sulfur-containing cathode. To suppress a shuttle mechanism and to prevent a loss of active material, the separator includes a base layer and a polysulfide barrier layer. The polysulfide barrier layer is formed on the cathode side of the separator.

Claims

1. A lithium-sulfur cell, comprising: a lithium-containing anode; a sulfur-containing cathode; and a separator arranged between the lithium-containing anode and the sulfur-containing cathode, wherein the separator includes a base layer and a polysulfide barrier layer including at least one polymer having polysulfide affinity which forms a reversible ionic bond with a polysulfide and at least one polyolefin-polyether copolymer, the polysulfide barrier layer formed on a side of the separator facing the sulfur-containing cathode.

2. The lithium-sulfur cell of claim 1, wherein the polysulfide barrier layer includes a mixture of the at least one polymer having polysulfide affinity and at least one polysulfide-tight material.

3. A lithium-sulfur cell, comprising: a lithium-containing anode; a sulfur-containing cathode; and a separator arranged between the lithium-containing anode and the sulfur-containing cathode, the separator including a base layer and a polysulfide barrier layer, the polysulfide barrier layer formed on a side of the separator facing the sulfur-containing cathode from a mixture of at least one polymer having polysulfide affinity and at least one polysulfide-tight material, wherein the polysulfide barrier layer includes at least one polyolefin-polyether copolymer, the polysulfide barrier layer is formed on a side of the separator facing the sulfur-containing cathode, and during a synthesis of the mixture of at least one polymer having polysulfide affinity and at least one polysulfide-tight material, ceramic particles are inserted into a reaction product of the synthesis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and advantageous developments of the subjects according to the disclosure are illustrated by the drawings and are explained in the description hereinafter. It must be noted in this case that the drawings only have a descriptive character and are not intended to restrict the disclosure in any manner. In the drawings

(2) FIG. 1 shows a schematic cross section through an embodiment of a lithium-sulfur cell according to the disclosure; and

(3) FIG. 2 shows a schematic cross section through a further embodiment of a lithium-sulfur cell according to the disclosure.

(4) FIG. 1 shows a lithium-sulfur cell which comprises a lithium-containing anode 1, a sulfur-containing cathode 2 and a separator 3 which is arranged therebetween, i.e. between the lithium-containing anode 1 and the sulfur-containing cathode 2. In this case the separator 3 comprises a base layer 3a and a polysulfide barrier layer 3b which is constructed on the cathode side of the separator 3.

(5) The polysulfide barrier layer 3b can advantageously prevent polysulfides from penetrating the separator 3 and therefore from reaching the anode 1, and thus suppress a shuttle mechanism which otherwise could lead to a loss of active material.

(6) In order to ensure the barrier action, the polysulfide barrier layer 3b can comprise a polymer having polysulfide affinity, a polysulfide-tight, ceramic or polymeric material, or a mixture thereof.

(7) In the context of the embodiment shown in FIG. 2, the polysulfide barrier layer 3b is constructed as a multilayer, in particular double-layer, layer system 3b, 3b, in which one layer 3b comprises a polymer having polysulfide affinity and the other layer 3b comprises a polysulfide-tight ceramic material, wherein the polysulfide-tight layer 3b is constructed on the side of the layer 3b that has polysulfide affinity and which is facing away from the cathode 2.