Toward More Reliable Lithium–Sulfur Batteries: An All-Graphene Cathode Structure

Lithium–sulfur (Li–S) batteries are attracting increasing interest due to their high theoretical specific energy density, low cost, and eco-friendliness. However, most reports of the high gravimetric specific capacity and long cyclic life are not practically reliable because of their low areal specific capacity derived from the low areal sulfur loading and low sulfur content. Here, we fabricated a highly porous graphene with high pore volume of 3.51 cm3 g–1 as the sulfur host, enabling a high sulfur content of 80 wt %, and based on this, we further proposed an all-graphene structure for the sulfur cathode with highly conductive graphene as the current collector and partially oxygenated graphene as a polysulfide-adsorption layer. This cathode structural design enables a 5 mg cm–2 sulfur-loaded cathode showing both high initial gravimetric specific capacity (1500 mAh g–1) and areal specific capacity (7.5 mAh cm–2), together with excellent cycling stability for 400 cycles, indicating great promise for more reliable lithium–sulfur batteries.