A nanoflower structure rare-earth La3+ doping Sn3O4 with highly catalytic active interfaces as a sulfur host facilitates the conversion kinetics of polysulfides in high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur batteries are considered a favourable contender for next-generation energy storage systems owing to their high energy density (2600 Wh·kg−1). However, the severe "shuttle effect" of polysulfides and the slow redox kinetics involving phase transitions have seriously limited the commercialization of lithium-sulfur batteries. On this basis, in this paper, a type of nanoflower structure rare-earth lanthanum ion (La3+) doping Sn3O4 with a large number of catalytic active interfaces is designed via a facile one-step hydrothermal method. When serves as a capture centre to immobilize polysulfides, it exhibits a strong chemical adsorption capacity. Moreover, due to the unique 4 f electron configuration of the rare-earth elements, nanoflower structure La3+ doping Sn3O4 (La@Sn3O4) as sulfur-wrapped matrix has a strong catalytic activity, which can effectively accelerate the conversion process of polysulfides. At the same time, the catalytic mechanism of La@Sn3O4/S composite cathode material targeting the solid to liquid phase transformation of polysulfides is effectively revealed via in-situ Raman spectroscopy test and the initial discharge capacity can reach 1429.6 mAh·g−1 at a current density of 0.1 C, and the capacity retention rate is 76.5 % after 130 cycles.