Lithium-sulfur batteries (LSBs) have been considered as one of the most promising energy storage systems owing to their high theoretical energy density and abundant sulfuric resources. However, their commercial application is limited by rapid capacity decline and low Coulombic efficiency. Metal-organic frameworks (MOFs) made of metallic nodes and organic ligands can suppress polysulfide shuttling and promote redox kinetics. In this paper, the effects of crystallographic dimensions and metallic categories on chemical performance of LSBs have been meticulously explored electrochemical performance. As a result, exposed Ni active sites in a lamellar Ni-MOF was found to deliver a superior electrochemical performance. The as-assembled LSBs with 2D-Ni-MOF/CNTs cathode deliver a much superior initial discharge capacity, (820 mAh g-1 at 0.5 C), and exhibit excellent cycling stability over 550 cycles than those analogues of 3D stereoscopic Ni-MOF and 2D lamellar Co-MOF. This work proposed a perspective in elevating LSBs performance through synergistic optimization of the MOFs dimensions and the metallic nuclei in the cathodes.
Keywords: crystallographic dimensions; lithium-sulfur batteries; metal-organic frameworks; metallic nucleus; soluble polysulfides.
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