Polyzwitterions Functionalized Nafion Barrier Toward High Performance Lithium‐Sulfur Batteries

Abstract

AbstractLithium‐sulfur (Li−S) batteries have emerged to be the next generation energy storage batteries due to their high theoretical capacity and low cost. Nevertheless, the growth of lithium dendrites and the notorious shuttle effects of lithium polysulfides (LiPS) during electrochemical reactions hinder the further application of Li−S batteries. Herein, a novel imidazolium‐type polyzwitterions functionalized Nafion barrier was successfully prepared by grafting the zwitterion 3‐(1‐vinyl‐3‐imidazolio) propanesulfonate onto Nafion. The polyzwitterions can promote the lithium salts dissociation to fast ion distribution, and guide Li+ uniform nucleation for effective dendrite inhibition. In addition, with the strong interaction between the imidazole rings and LiPS, the polyzwitterions functionalized separator can capture LiPS thus suppressing the shuttle effects during Li−S battery cycling. Consequently, the symmetrical Li cell with polyzwitterions can provide superior cycling stability over 1200 h with no dendrite formation at a high current density of 3 mA cm−2. The polyzwitterions enhanced Li−S battery can deliver a reversible specific capacity of 460 mA h g−1 at 1 C for over 500 cycles, demonstrating a great promise in the development of high efficiency and high safety Li−S batteries.