The invention relates to an isolating layer used for a
lithium-
sulfur battery. The surfaces of a positive
electrode, a negative
electrode or a diaphragm are coated with the isolating layer, or the isolating layer can be attached to the space between the positive
electrode and diaphragm or between the negative electrode and diaphragm in an independent sheet-shaped
solid way so as to protect the battery; and the functional isolating layer comprises three components, including a functional agent, a binder and a conductive agent, wherein the functional agent is a
lithium sulfonate group-containing carbon material, a
polymer, or a mixture of the carbon material and the
polymer, and a material formed by the carbon material and the
polymer and corresponding
metal oxides thereof based on different proportions in a mixing manner. By virtue of
lithium sulfonate included in the components of the isolating layer, lithium
ion concentration in an
electrolyte and
ion mass transfer rate are improved; by virtue of the existence of
sulfonate, the
ionic conductivity can be reinforced, and by matching with the use of the binder, an obvious chemical blocking and
adsorption effect on lithium
polysulfide is achieved, so that dissolving and
diffusion are effectively suppressed, and surface
passivation, formed by deposition of insoluble lithium
polysulfide, on the lithium negative electrode surface can be relieved; and meanwhile, by virtue of the addition of the conductive agent, the
internal resistance of the battery is lowered.