Fabrication of a CoFe ₂ O ₄ -Based Interlayer for the Li–S Battery with Suppressed Shuttle Effect and Improved Reaction Kinetics

The practical implementation of Li–S batteries is limited by poor S utilization as a result of the soluble polysulfide shuttle effect combined with slow reaction kinetics. To enhance S utilization, in our present work, a CoFe2O4-based interlayer is introduced between the S cathode and commercial separator, which effectively suppresses active S species diffusion from the cathode region, thanks to the adsorption capability and catalytic activity of CoFe2O4 to lithium polysulfides. Notably, introducing a CoFe2O4-based interlayer, the Li–S battery shows a high initial discharge capacity (905.8 mAh g–1) at 3C with a capacity decay rate of 0.095% per cycle for 500 cycles.