Realizing fast polysulfides conversion within yolk-shelled NiO@HCSs nanoreactor as cathode host for high-performance lithium-sulfur batteries

Abstract

A rechargeable lithium–sulfur (Li–S) battery has been considered a promising candidate due to its superior theoretical capacity and energy density. However, the shuttle effect from insufficient adsorption, poor diffusion-transfer, and deteriorating catalytic behavior restrain its further applications. In the present work, we report a yolk–shell NiO@HCSs nanoreactor with a nanoparticle NiO-core and a conductive carbon-shell as an Li–S battery cathode, in which sulfur is trapped in the void between the NiO-core and the carbon-shell. On the one hand, the YS NiO@HCSs structure can afford sufficient interspace for absorbing sulfur, while the nanoparticle NiO-core shows excellent adsorption ability towards LiPSs. On the other hand, the conductive carbon-shell and the yolk–shell framework with continuous pathways accelerate the dispersion and diffusion of LiPSs. More importantly, the NiO encapsulated in a yolk–shell nanoreactor serves as a metal catalytic site to accelerate the conversion of LiPSs, realizing fast adsorption–diffusion–conversion and promoting the stability of a YS NiO@HCSs electrode. As a result, the S/YS NiO@HCSs cathode displays a high discharge capacity of 1210.4 mA h g⁻¹ at 0.2C and excellent cyclability for 300 cycles at 1C with an average capacity decay of 0.06% per cycle. This work shows an effective yolk–shell NiO@HCSs nanoreactor for enhancing LiPS conversion kinetics in high-performance Li–S batteries.