LAUSR

Abstract Polysulfides can be captured rapidly by defects, which possess strong catalytic redox abilities. Species of defects have important influence on rate performance of metal-sulfur electrodes. However, catalytic reaction mechanisms have not been explored in depth. This paper focuses on comparing differences between intrinsic defect carbon materials (IDC) and external introduced defect carbon materials (EIDC) in promoting polysulfide redox abilities and exploring catalytic redox reaction mechanism deeply. Results show that IDC have stronger catalytic redox reaction abilities than EIDC, which is mainly due to stable C–S bonds on surface of IDC. After cycling, C–S bond contents in IDC electrodes maintain more than 70 %. During cycling process, C–S bonds can quickly adsorb polysulfides and promote their conversion into final products, thereby achieving high rate performance. Weak catalytic redox abilities of EIDC electrodes is mainly due to loss of C–S bonds. When the current density is 5C, capacities of IDC electrodes is twice as much as that of EIDC electrodes. Good rate performance of IDC electrodes reflects important roles of stable C–S bonds in promoting redox reaction of polysulfides, which has important research significance for preparation of carbon-based composite electrodes.