A Compact Nanoconfined Sulfur Cathode for High-Performance Lithium-Sulfur Batteries

A high-sulfur-loading cathode is the most essential component for lithium-sulfur batteries to gain considerable energy density for practical applications. The main challenges associated with high-sulfur-loading electrodes are low specific capacity caused by the insulating nature of sulfur and poor stability arising from dissolution of polysulfides into most organic electrolytes. Here, we propose a hierarchically structured sulfur cathode that simultaneously tackles both problems associated with high-sulfur-loading electrodes. Specifically, titanium monoxide hollow nanospheres are packed space efficiently and closely connected by carbon layers into microsized “clusters” as the sulfur host. As a result of this hierarchical structure design, the nanoscale reaction chambers and the microscale conductive networks cooperatively promise high capacities of sulfur at various current densities. During cycling, the titanium monoxide polar layer in every nanocompartment effectively hinders the dissolution of polysulfides, resulting in superior cycling stability for the high-sulfur-loading electrode.