CeO2/GR interlayer prepared to reinforce the cathode and promote the electrochemical performance of lithium-sulfur batteries

The interlayer which was assembled as an "additional electrode" between the cathode and separator, has become a research hotspot to promote the electrochemical performance of Lithium-Sulfur batteries (LSBs). Herein, we have prepared cerium-oxide/graphene (CeO2/GR) interlayer by a simple secondary scraping and coating method, in which the uniformed CeO2 nanoparticles as diameter size of 10 nm with complete crystal structure were in- situ formed on GR by hydrothermal method and high temperature annealing. CeO2 nanoparticles, as a polar metal oxide can provide a large surface area to adsorb polysulfide, improve the utilization rate of the active material and inhibit the shuttle effect, GR can improve the conductivity of cathode materials. As a result, the electrochemical performance of LSBs can be significantly improved by CeO2/GR interlayer. As the best one, the battery with CeO2/GR-1.8 interlayer showed an excellent capacity of 1488 mA h g-1 under a current density of 167.5 mA g-1 (0.1 C). Besides, it exhibited a long-term cyclability with an inferior capacity decay of 0.13% per cycle and a super-high coulombic efficiency of 99.96% within 350 cycles. The excellent electrochemical performance could due to the extra polysulfides adsorbed by CeO2, which contributed uniformly on the interlayer surface could be recycled and utilized during the long time cycling.