Designable Hierarchical Cathode for a High-Efficiency Polysulfide Trapper Toward High-Performance Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries have attracted wide attention due to their high theoretical capacity and energy density. However, practical application of lithium–sulfur batteries is still hampered by many problems, especially poor conductivity of sulfur and the polysulfide shuttle. To resolve these problems, we have designed a sulfur host with a hierarchical structure. This host is made by growing MnO2 nanosheets on one side of carbon paper, of which the other side is coated with carbon nanotubes modified with g-C3N4. The fabricated sulfur host provides a physical shield and chemical adsorption against polysulfide shuttling. Moreover, the conductive framework of carbon nanotubes can allow efficient impregnation of sulfur and facilitate electron transport. Benefiting from these synergetic effects, the as-made sulfur cathode with 70.3 wt.% sulfur content delivers enhanced electrochemical performances including a high capacity, an excellent rate performance and a superior cycling stability.