Constructing high-throughput and highly adsorptive lithium-sulfur battery separator coatings based on three-dimensional hexagonal star-shaped MOF derivatives.

ABSTRACT

The electrochemical performance of high-performance lithium-sulfur (Li-S) batteries is affected by many factors such as shuttle effect and lithium dendrites. To effectively solve this problem, a hexagonal star-shaped composite catalyst containing Co-N-C active sites (Co-NC-X) has been rationally developed under the joint action of Zn2+ and Co2+ bimetallic ions. By modifying it to the Li-S battery separator, Co-NC-X can not only act as a physical barrier to effectively prevent the diffusion of lithium polysulfide (LiPS), but also the special morphology can expose more active sites and have a strong chemisorption effect on LiPS, which effectively promotes the redox conversion of LiPS and mitigates the shuttle effect. Li-S battery with Co-NC-X exhibits excellent electrochemical performance. It has a high specific capacity and stable cycling performance, with an initial discharge capacity of 1406.9 mAh·g-1 at 0.2 C and 876.8 mAh·g-1 at 2 C, and a lower capacity decline rate of 0.093 % for 500 cycles.