Polymer lithium–sulfur batteries with a Nafion membrane and an advanced sulfur electrode

Abstract

The development of lithium–sulfur (Li–S) battery technology is experiencing a critical challenge due to the migration of the soluble polysulfide species from the cathode to the lithium–metal anode which results in poor cyclability of the cell. To overcome the above issue, use of lithium-ion conductive membranes instead of the traditional porous Celgard membrane as the separator/electrolyte is one of the promising approaches. In this study, a lithiated Nafion membrane is used as a cation-selective electrolyte for Li–S batteries to suppress the polysulfide diffusion. An advanced cathode structure containing a high-surface activated carbon nanofiber (AC-CNF) current collector filled with dissolved lithium polysulfides and a thin AC-CNF upper current collector is used to improve the sulfur utilization. The Li–S battery system with the lithiated Nafion membrane and the sandwich cathode exhibits significantly enhanced cyclability relative to the cells with the traditional liquid-electrolyte integrated porous separator.