The good flexibility of graphene makes it possible to effectively relieve the volume change of the sulfur. Graphene as a sulfur host can improve the conductivity of the cathode. Graphene has many advantages, such as high specific surface area, excellent electrical conductivity, high structural stability, high strength, high flexibility, and easy functionalization. Among the carbon materials, graphene has received extensive attention. The use of the carbon-sulfur composite cathode is considered to be an effective way to realize the improvement.

In recent years, researchers have conducted a lot of work on the modification of cathode materials for the improved performance of LSB. (3) The repeated volume changes of elemental sulfur during the cycling process. (2) The dissolution of the reaction intermediate (Li 2S n, 4 ≤ n ≤ 8) into the electrolyte. Therefore, LSB is regarded as the most potential substitute for commercial LIB, but the performance of LSB is still difficult to reach the current level of commercial LIB, for these reasons: (1) the low conductivity of elemental sulfur and its discharge products (Li 2S 2 and Li 2S). In addition, sulfur also has the advantage of being a sufficient resource, having low cost, and being harmless to the environment. The low working voltage of LSB (~2.2 V) can adapt to the commercial need. Elemental sulfur has a high theoretical specific capacity of 1675 mAh g −1, indicating its great potential as energy storage material. Recently, a lithium-sulfur battery (LSB) has caught the attention of researchers all over the world. Therefore, the search for a new rechargeable battery with high energy density has become urgent. After development for more than 20 years, the specific capacity of the commercial cathode material is close to its theoretical value, which still cannot meet the growing energy need. Lithium-ion battery (LIB) is the most widely used rechargeable battery, with many advantages: high energy density, long service life and low cost.

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