High rate capability of S-doped ordered mesoporous carbon materials with directional arrangement of carbon layers and large d-spacing for sodium-ion battery

Abstract

Carbonaceous materials are promising anode materials for sodium-ion batteries (SIBs). However, the highly ordered/graphitized carbon materials own the narrow interlayer spacing and limited active sites, which hinder the reversible insertion/extraction of Na+ thus resulting in slow kinetic rate and low theoretical capacity. Herein, an ordered mesoporous carbon material with directional arrangement of carbon layers is prepared through surface-anchoring-template-carbonization method. The effects of different carbonization temperatures and content of S-doping on the morphologic structure and the sodium storage performance of the pitch derived ordered mesoporous carbon (OMCP) materials are systematically investigated. It is found that S-doping enlarges the d-spacing and increases the active sites of the OMCP, thus improving the sodium storage reaction kinetics. The resulting S-doped OMCP exhibits excellent sodium storage properties, especially in the rate performance (266.7 mAh g−1 at the current density of 2 C). In addition, electrochemical kinetics tests using cyclic voltammetry and galvanostatic intermittent titration technique reveal that the enhanced sodium storage performance of OMCP is attributed to the presence of numerous active sites and the enlarged d-spacing, which improve the diffusion coefficient of Na+.