Review on advanced functional separators for lithium-sulfur batteries

As the demand to energy storage devices for portable electronics and electric vehicles increase, lithium-sulfur (Li-S) batteries have attracted much attention for its extremely high energy density. However, the low coulombic efficiency, rapid fading capacity, and poor cycle performance of lithium anode hinder the demonstration of practical Li-S cells. The advanced functional separator/interlayer system have been proposed and verified to retard the shuttle of polysulfides and extend the cycling life of a Li-S cell. In this review, the progress on multifunctional separators/interlayers for lithium sulfur batteries are summarized, including permselective separator inhibiting polysulfide shuttles, separator with low interfacial resistance, and composite electrolyte stabilizing anode and retarding the formation of Li dendrites. New insights into challenge and opportunities of multifunctional separator/interlayer system are also prospected.