Carbon doping endows silicon oxide with enhanced redox kinetics of polysulfides.

Carbon-doped SiO 2 is synthesized by the in situ carbonization of halloysite. Carbon atoms partially substitute O atoms to form Si-C bonds and manipulate the localized electronic states of Si atoms, thereby endowing SiO 2 with suitable adsorption strength and reducing the activation energy barrier for polysulfides in the sulfur redox. The C-SiO 2 /S cathodes for Li-S batteries exhibited superior electrochemical performance.