A Strategy for configuration of an integrated flexible sulfur cathode for high-performance lithium-sulfur batteries

Lithium-sulfur batteries are regarded as promising candidates for energy storage devices owing to their high theoretical energy density. The practical application is hindered, however, by low sulfur utilization and unsatisfactory capacity retention. Herein, we present a strategy for configuration of the sulfur cathode, which is composed of an integrated carbon/sulfur/carbon sandwich structure on polypropylene separator that is produced using the simple doctor-blade technique. The integrated electrode exhibits excellent flexibility and high mechanical strength. The upper and bottom carbon layers of the sandwich-structured electrode not only work as double current collectors, which effectively improve the conductivity of the electrode, but also serve as good barriers to suppress the diffusion of the polysulfide and buffer the volume expansion of the active materials, leading to suppression of the shuttle effect and low self-discharge behavior. An integrated flexible sulfur cathode consisting of a carbon/sulfur/carbon sandwich structure coated on a polypropylene separator was prepared by the doctor-blade method. This sulfur cathode could enhance the electronic conductivity, toleration of volume expansion, and control of the polysulfide diffusion, thereby improving the electrochemical performance of lithium-sulfur batteries.