CeO2 nanoparticles decorated CMK-3 as high-performance sulfur host for Li-S batteries

Abstract

The development of Li-S batteries is hindered by some inherent drawbacks such as the shuttle effect of lithium polysulfides and the volume expansion of sulfur. Herein, 3–6 nm CeO2 nanoparticles decorated CMK-3 (CMK-3 @CeO2) is prepared and used as the sulfur host for Li-S batteries. As a conductive carbon support, CMK-3 can improve the electrical conductivity of sulfur-based electrode, and its mesopores provide the space required for the volume expansion of sulfur. Meanwhile, the decorative CeO2 nanoparticles can not only change the non-polar carbon surface into the polar CeO2 surface for capturing lithium polysulfides, but also accelerate the redox reaction of lithium polysulfides, which effectively inhibits the shuttle effect of lithium polysulfides. Therefore, compared to pure CMK-3 supported sulfur (CMK-3 @S), CMK-3 @CeO2 supported sulfur (CMK-3 @CeO2 @S) exhibits better electrochemical performance, such as a discharge capacity of 686 mA h g−1 after 800 cycles at 1 C. Besides, the size effect of CeO2 nanoparticles on the electrochemical performance of CMK-3 @CeO2 @S is also studied. This work provides a simple method for improving the electrochemical performance of CMK-3 as the sulfur host, and this strategy can be extended to the other metal oxides decorated sulfur host materials.