Gyroidal Porous Carbon Activated with NH3 or CO2 as Lithium−Sulfur Battery Cathodes

Abstract

Ordered mesoporous carbon materials, prepared from co‐assembly of a block copolymer and a commercial resol, were investigated as a sulfur host for LiS‐battery cathodes. We studied two activation methods for such carbons, namely annealing in ammonia (NH3) and carbon dioxide (CO2). We found that both activation environments drastically increased the specific surface area and establish a micro‐ and mesoporous pore structure. Treatment with NH3 also introduced nitrogen groups, which increased the initial specific capacity. The non‐activated carbon yielded carbon/sulfur cathodes with an initial capacity of ∼900 mAh/gsulfur (150 mAh/gsulfur after 100 cycles). The initial capacity was increased to 1300 mAh/gsulfur for the NH3 activated sample but with poor cycling stability. Enhanced performance stability was found for the CO2 treated sample with an initial capacity of 1100 mAh/gsulfur (700 mAh/gsulfur after 100 cycles).