An acetylene black modified gel polymer electrolyte for high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered to be a promising energy storage system for the future. However, a series of problems, such as sulfur acting as an insulator, the shuttle effect and the growth of lithium dendrites, have hindered their commercial application. To simultaneously tackle these three challenges, a composite quasi-solid/gel polymer electrolyte consisting of a nonporous supporting layer made by lightly cross-linked PMMA and a coated acetylene black layer was prepared to realize high-performance Li-S batteries. The nonporous polymer membrane was used to efficiently suppress the growth of lithium dendrites and promote the formation of a stable solid electrolyte interphase, while the acetylene black layer facing the sulfur cathode can hinder the polysulfide diffusion and promote rapid electron transfer. The as-prepared lithium-sulfur batteries show good cycling stability for 200 cycles, with an initial specific capacity of 994.5 mA h g^-1 at 1C and perfect rate performance with a reversible capacity of 657.5 mA h g^-1 at 3C. The growth of lithium dendrites was also effectively suppressed. This work provides a new concept for the structural design of Li-S batteries and promises to promote the further commercialization of Li-S batteries.