A Mild Strategy to Strengthen Three Dimensional Graphene Aerogel for Supporting Sulfur as a Free-standing Cathode in Lithium-Sulfur Batteries

Recently, three dimensional graphene aerogel (3DGA) supported sulfur microparticles was used as a cathode material for lithium-sulfur batteries, which was considered as one of the most promising next generation rechargeable batteries due to its ultra-high theoretical specific capacity (1675 mAh/g). However, the mechanical strength of 3DGA remains an issue for further application. Herein, a strengthened 3DGA (S3DGA) was achieved by soaking in a low concentration ammonia solution at a relative low temperature. Then the S3DGA loaded sulfur (S3DGA-S) was cut into a round piece and directly used as a cathode without additional binders or conductive additives in Li-S batteries. The mechanical strength, microstructure, and electrochemical properties were investigated by compare with a 3DGA prepared without strengthen. The S3DGA-S presented good mechanical strength, excellent capacity retention, and lower electrochemical impedance.