| 초록 |
In this study, we demonstrate a far different approach to enhance the performance (in particular, the rate capability) of lithium sulfur batteries from the conventional methodology to spatially confine the dissolvable polysulfide, such as the employment of mesoporous carbon host, the graphene coating, and the insertion of carbon interlayer. Although over five decades have passed since the concept of LSBs was first suggested, the redox mechanism of sulfur in non-aqueous electrolytes is still under debate. In particular, the argument on missing charges has been dealt with as a main issue to understand the electrochemical sulfur redox behavior. Recently, Lu and Gasteiger suggested a very reasonable solution to address the argument that the missing charge is originated from the slow chemical disproportionation reaction, which is an origin of the poor rate capability of LSBs. Interestingly, we found that the S82- intermediates which can be generated by only the slow chemical disproportion at 2V on carbon can be formed on a specific metal compound via fast electrochemical reduction. This unique phenomenon led to the markedly enhanced rate capability of LSBs. Also, combining with the conventional methodology to spatially confine the dissolvable polysulfide, we could obtain the improved cyclability as well as rate capability. |
