O-, N-Coordinated single Mn atoms accelerating polysulfides transformation in lithium-sulfur batteries

Abstract

Desired to improve the capacity and cycle stability of lithium sulfur batteries, it is urgent to solve the insulating nature of sulfur cathode, sluggish electrochemical kinetics, and severe shuttle effect associated with polysulfide intermediates. Here single manganese (Mn) atoms implanted in oxygen and nitrogen double-doped hollow carbon sphere frameworks (Mn/C-(N, O)) are prepared as electrocatalyst and anchoring sites for lithium sulfur batteries. O, N-coordinated single Mn atoms can rich in atomic active sites, anchor polysulfides through strong Lewis acid-base interactions. Meanwhile, Mn cofactors show high catalytic activity on the conversion reaction of polysulfides. Moreover, the abundant pores in conductive carbon frameworks can facilitate electrolyte diffusion while simultaneously promote the dynamic protection of the cathode structure during cycling. Consequently, S@Mn/C-(N, O) exhibits an excellent cycling stability with an initial capacity of ~900 mAh g⁻¹ at 1 C with only 0.05% capacity decay per cycle after 1000 cycles. The theoretical simulation results and the enhanced electrochemical performance show the important role of single atom in accelerating polysulfides transformation and suppressing the "shuttle effect".