A ferromagnetic heterostructure nanowire enables high rate and stable lithium-sulfur battery

The shuttle effect of lithium polysulfides is widely regarded as one of the major issues of lithium-sulfur batteries, leading to low active material utilization and rapid capacity decay. The surface chemistry at the cathode/electrolyte interface is crucial for suppressing polysulfides shuttling and enhancing the electrochemical performance of the batteries. In this work, a heterostructure ferromagnetic transition metal oxide (Co3O4@Fe3O4 nanowire) supported on carbon cloth (CC) was designed to improve the adsorption and conversion kinetics of LiPSs and suppress the shuttle effect. The crystal phase in the heterostructure can tune the crystal strain and provide additional kinetic energy for surface reconstruction, which improves the number of accessible catalytic active sites and reduces the kinetics barrier for polysulfides redox reaction, and an increased magnetic property and a built-in electric field have been introduced at the interface. The built-in heterostructure promotes electron transfer and charge distribution within heterogeneous structures and serves as active sites for buffering LiPSs shuttling, thus, enhances the redox kinetics of LiPSs and fosters uniform Li2S deposition and high sulfur utilization during cycling. The Co3O4@Fe3O4-CC heterostructure nanowire-based sulfur composite cathode exhibits high initial capacity (1678.5 mAh/g at 0.1C), excellent rate capacity (860.6 mAh/g at 2C), and remarkable cycling performance (low decay of 0.017 %/cycle). This study highlights a novel ferromagnetic heterostructure nanowire strategy to suppress the shuttle effect and improve the performance of lithium-sulfur batteries.