Nitrogen doped multistage porous carbon for enhancing the adsorption-catalytic conversion of polysulfides in Li–S batteries

Lithium-sulfur (Li–S) batteries are regarded as promising next-generation electrochemical energy-storage devices owing to their high theoretical capacity of 1672 mAh/g for sulfur and high energy density of 2600 Wh kg−1. However, severe active sulfur losing and capacity fading originated from “shuttle effect” restrict their practical applications. Herein, nitrogen doped multistage porous carbon (denoted as MPC) was prepared as a novel sulfur host for Li–S batteries. Our strategies for the shuttle effect inhibition consist of three parts as described below, including accelerating conversion of lithium polysulfides by N-doping, blocking the shuttle channels by MPC, and enhancing adsorbability from MPC to lithium polysulfides. Expectantly, the Li–S batteries with the MPC@S cathode show high specific capacity of 508 mAh/g after 505 cycles when the sulfur loading is as high as 3.80 mg cm−2.