Defect Engineering in a Multiple Confined Geometry for Robust Lithium–Sulfur Batteries

摘要

The decay of lithium-sulfur (Li-S) batteries is mainly due to the shuttle effect caused by intermediate polysulfides (LiPSs). Herein, a multiple confined cathode architecture is prepared by filling graphitized Pinus sylvestris with carbon nanotubes and defective LaNiO3-x (LNO-V) nanoparticles. The composite electrode with high areal sulfur loading of 11.6 mg cm(-2) shows a high areal specific capacity of 8.5 mAh cm(-2) at 1 mA cm(-2) (0.05 C). Both experimental results and theoretical calculations reveal that this unique structure not only provides physical restriction on LiPSs within microchannels but also offers strong chemical immobilization and catalytic conversion of LiPSs attributed to the spin density around oxygen vacancies of LaNiO3-x. These oxygen vacancies elongate the S-S and Li-S bonds and make them easy to break. Furthermore, the lengthwise channels derived from cytoderm restrict the transverse diffusion of polysulfides, leading to a uniform areal current and thus homogeneous lithium infiltration. This suppresses the corrosion of the lithium anode due to polysulfides confinement. The discovery of the multiple confined structure that provides chemical adsorption, fast diffusion, and catalytic conversion for polysulfides can broaden the application of biomass materials and offer a new strategy to achieve robust Li-S batteries.