CO2-Derived Porous Carbon Cathode and High Nitrogen Content Interlayer for Inhibiting the Shuttle Phenomenon

Abstract

The suppression of the shuttle phenomena of lithium polysulfides (LiPSs) is very important for improving the performance of lithium-sulfur (Li-S) batteries. Among various works to inhibit the shuttle phenomenon, approaches using an interlayer, which have the advantage of maintaining stable performance even in a very long charging and discharging process, have been attempted. This work introduces highly porous carbon for both sulfur-based active material composite and interlayer synthesized through CO2 conversion. The porous carbon cathode enables uniform distribution of active materials without agglomeration of insoluble solids such as Li2S and Li2S. The interlayer made via electrospinning in this work has a high porosity, so it is 30 wt% lighter than the conventional fiber-type interlayer. Additionally, the interlayer is doped with more than 15% of N atoms including pyridinic-N and pyrrolic-N on the carbon surface. Excess N atoms prevent transport of LiPSs to the Li metal electrode based on the chemical interactions with soluble intermediates, and improve conductivity, which results could induce superior electrochemical reaction and exhibit high specific capacity. As a result, the assembled cells deliver a capacity of 707 mAh g−1 up to 500th cycle at 0.5 C current density, and exhibit about 700 mAh g−1 specific capacity at a high current density of 7.0 C.