Novel Lithium-Sulfur Battery Separators Modified with Porous Mn3O4 Micrometer Cubes/rGO and Their Electrochemical Properties
Lithium-sulfur batteries are regarded as a new generation of energy storage devices with great potential for development due to their high theoretical specific capacity(1 675 mAh∙g-1)and energy density(2 567 Wh∙kg-1),as well as the abundance of sulfur resources.However,the shuttle effect of polysulfides generated during charging and discharging,the poor conductivity of sulfur and lithium sulfide,and the low sulfur utilization rate have greatly restricted the wide application of lithium-sulfur batteries.In this study,a team of researchers successfully produced porous Mn3O4 micrometer cubes with abundant pore structure.The process involved preparing the MnCO3 precursor using the water bath method,followed by calcination.The addition of GO and secondary annealing led to the creation of porous Mn3O4 micrometer cube/reduced graphene oxide(Mn3O4/rGO)composites,which were then used to modify commercial diaphragms to enhance the electrochemical performance of lithium-sulfur batteries.The study's results were auspicious,as the composite structure demonstrated excellent electrochemical performance in lithium-sulfur battery diaphragm applications.Specifically,it exhibited a reversible capacity of 1 090 mAh∙g-1 at 0.1 C and 877 mAh∙g-1 even at a high current density of 1 C.After 400 cycles at 1 C,the capacity remained at 422 mAh∙g-1,further attesting to the outstanding electrochemical performance of Mn3O4/rGO nanomaterials.The researchers found that the inner pore-rich Mn3O4 micro boxes provided abundant active sites for the catalytic conversion of lithium polysulfides,while the outer interconnected three-dimensional rGO network with high electrical conductivity provided a natural channel for lithium-ion shuttling and restricted the shuttling effect of polysulfides.Together,these two components limited the shuttling effect of LiPSs,leading to improved cycling stability of LSBs and providing valuable insights into addressing the issue of lithium polysulfide shuttling in lithium-sulfur batteries.
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