Rice husks-derived hierarchical porous SiO2@C as efficient polysulfide mediator for Li-S batteries.

• A hierarchical porous SiO 2 @C host derived from waste rice husks was fabricated. • Improved performance was achieved in the SiO 2 @C-2.5S cathode for Li-S cells. • The cathode combined the physical confinement and chemical affinity toward LPSs. The serious shuttle effect and sluggish redox kinetics hinder the practical implementation of Li-S batteries. Here, we proposed a general method for large-scale synthesis of hierarchical porous SiO 2 @C host derived from waste rice husks. The prepared SiO 2 @C-2.5S cathode exhibits superior electrochemical properties, which can be attributed to the physical adsorption of porous carbon shell and chemical anchoring effect of SiO 2 nanoparticles. Moreover, the hierarchical porous carbon matrix provides a highly conductive channel for rapid electron and ion transport, and offers enough space for the volume expansion of elemental S during the reaction. [ABSTRACT FROM AUTHOR]