Lithium-sulfur (Li-S) batteries are among the most promising candidates for future high-energy, low-cost energy-storage systems. However, still many challenges have to be solved on the way to their commercialization. One of the most prominent of those is related to the polysulfide shuttle. In recent years, various approaches have been developed to contain, control or eliminate its effects, and thus to achieve higher specific charge, higher coulombic efficiencies and longer cycling life. One of recurring approaches is best described as introducing 'polysulfide barriers', either inorganic or polymeric membranes with lithium-ion conduction or interlayers with adsorptive properties, preventing polysulfides from reaching the lithium metallic anode. All of these approaches result in improved performance and longer cycling life of the Li-S battery. However, little attention has been given to the commercial viability of such solutions. Here we present a simple model to evaluate the practicability of polysulfide barriers in terms of gravimetric and volumetric energy densities as well as cost. We take into account the effects of barrier thickness, the physical properties and cost of the materials they are made of, as well as account for sulfur loading when assessing the viability of polysulfide barrier implementation into a practical Li-S cell. The Li-S battery combines several attractive properties, most importantly a high theoretical energy density, high theoretical specific charge and low cost.1-5 Moreover, the abundance of elemental sulfur -the active material in the Li-S battery -makes commercialization of this system even more desirable. The main drawback of sulfur as the active material is its insulating nature, which also applies to the Li 2 S, an end product of the lithiation reaction upon discharge. 5,6 However, the most detrimental process within Li-S cells is the polysulfide shuttle, which is triggered when highly soluble long-chain polysulfides are formed upon sulfur lithiation. Due to their high mobility in electrolyte, they can leach out from the positive electrode and reside in the electrolyte. There, polysulfides disproportionate in contact with other polysulfides or sulfur, and are partially oxidized or reduced when interacting with the positive or negative electrode, respectively. This leads to 'endless' red-ox shuttle, often referred to as the 'polysulfide shuttle '. 4,7 In addition, a part of the dissolved polysulfides can also be fully reduced at the negative electrode, forming an insulating layer; as a result, part of the active material is irreversibly lost and at the same time the resistance of the negative electrode is increased. The polysulfide shuttle therefore lowers the efficiency of the cell, reduces its specific charge and compromises its lifetime. [8][9][10][11][12] In recent years, numerous solutions have been proposed to reduce the effects of polysulfide shuttle and to control it. These approaches include encapsulation by or addition of adsorbing inorganic materials, polymers and their...