| 초록 |
Graphene oxide frameworks (GOFs)–formed by crosslinking graphene oxide (GO) sheets with linker molecules–possess an ion selectivity through their well-defined sub-nanochannels. The size of such channels can be tuned by a linker molecule, and it gives us the advantage of being able to modify the chemical properties of GOF when a linker has a specific functional group. Here, a GOF-based functional separator was elaborately designed and fabricated to mitigate the shuttle effect of lithium polysulfide (LiPS) in Li-S batteries. The linker molecule with Fe-N complex–which is known as having an affinity with LiPS–was chosen, also forming nanochannels with a size of about 1 nm in the GOF. Accordingly, an undesired transport of LiPS is suppressed both chemically and physically, respectively. Furthermore, as Fe elements are coordinated with N moieties in Fe-N complex, the atom utilization can be improved by preventing Fe aggregation. As a result of employing the GOF-based functional separator into a Li-S battery, it effectively prevents the shuttle effect and also promotes the reduction reaction of LiPS to provide a high discharge capacity during the cycles. |
