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 (NH 3 ) and carbon dioxide (CO 2 ). We found that both activation environments drastically increased the specific surface area and establish a micro‐ and mesoporous pore structure. Treatment with NH 3 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/g sulfur (150 mAh/g sulfur after 100 cycles). The initial capacity was increased to 1300 mAh/g sulfur for the NH 3 activated sample but with poor cycling stability. Enhanced performance stability was found for the CO 2 treated sample with an initial capacity of 1100 mAh/g sulfur (700 mAh/g sulfur after 100 cycles).